Buick Encore Owners & Service Manuals

Buick Encore: Supplemental Inflatable Restraints - Diagnostic information and procedures

Buick Encore 2012-2019 Service Manual / Accessories & Equipment / Cellular, Entertainment, and Navigation / Supplemental Inflatable Restraints - Diagnostic information and procedures

DTC B0000: Vehicle speed information circuit not plausible

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B0000 5A

Vehicle Speed Information Circuit Not Plausible

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The radio receives a vehicle speed signal from the electronic brake control module in order to correlate actual vehicle speed to the movement of the vehicle calculated by the navigation system and reported serial data.

Conditions for Running the DTC

  • Radio ON.
  • Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

  • Vehicle speed from serial data is more than 5 km/h (3 mph) and vehicle speed pulse from the electronic brake control module is 0 km/h (0 mph).
  • Vehicle speed calculated from the navigation processing software is more than 36 km/h (22 mph) and vehicle speed pulse from the electronic brake control module is 0 km/h (0 mph) for 10 seconds continuously.

Action Taken When the DTC Sets

  • Turn by turn route navigation may be inoperative.
  • Vehicle indicated location may be inaccurate.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC clears after 100 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

NOTE: Diagnose any antilock brake system (ABS) related DTCs before performing this diagnostic.

  1. Ignition OFF, disconnect the X4 harness connector at the A11 Radio.
  2. Ignition ON.
  3. Test for less than 1 V between the signal circuit terminal 20 and ground.

If 1 V or greater

  1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.

    Ignition ON.

  2. Test for less than 1 V between the signal circuit and ground.
  • f 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K17 Electronic Brake Control Module.

If less than 1 V

  1. Test for 3-7 Hz between the signal circuit terminal 20 and ground while operating the vehicle drive wheels at 5 mph (8 km/h).

If not 3-7 Hz

  1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the K17 Electronic Brake Control Module.

If 3-7 Hz

  1. Test or replace the A11 Radio.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio or electronic brake control module replacement, programming, and setup.

DTC B1020: Auxiliary electronic control unit (ecu) performance

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1020 00

Auxiliary Electronic Control Unit (ECU) Performance

Circuit/System Description

The radio communicates with the radio controls via serial data. This DTC indicates a fault in the radio controls.

The radio may continue to respond normally to faceplate functions when this DTC is set.

Conditions for Running the DTC

  • Ignition is ON or in the ACC position.
  • The system voltage is at least 9.5 V and no more than 15.5 V.
  • All the above conditions are present for greater than 10 seconds.

Conditions for Setting the DTC

The radio receives an improper status response indicating an internal ECU fault in the radio controls.

Action Taken when the DTC Sets

No action is taken.

Conditions for Clearing the DTC

  • A current DTC clears when the radio receives a proper status response message back from the radio control assembly.
  • A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

  • This DTC may be stored as a history DTC without affecting the operation of the radio controls.
  • If stored only as a history DTC and not retrieved as a current DTC, do not replace the radio controls.
  • If this DTC is retrieved as both a current and history DTC, replace the radio controls.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON.
  2. Verify DTC B1020 is not set.

If DTC B1020 is set

Replace the A22 Radio Controls.

If DTC B1020 is not set

All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio controls replacement, programming, and setup.

DTC B1025, B1035, B1045, OR B1055: Audio output circuit

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

DTC B1025

Left Front Audio Output Circuit

DTC B1035

Front Audio Output Circuit

DTC B1045

Left Rear Audio Output Circuit

DTC B1055

Right Rear Audio Output Circuit

For symptom byte information refer to Symptom Byte List

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and audio amplifier have a DC bias voltage that is approximately one half of battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5 V DC. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. The frequency (Hz) of the AC voltage signal is directly related to the frequency of the input (audio source playing) to the audio system. Both the DC bias voltage and the AC voltage signals are needed for the audio system to properly produce sound.

Conditions for Running the DTC

  • Ignition is ON or in the accessory position
  • The system voltage is 9-16 V
  • The test is run once during radio wake up

Conditions for Setting the DTC

B1025 01, B1035 01, B1045 01, B1055 01

The radio detects a short to voltage on the specified audio (+) or (-) circuit.

B1025 02, B1035 02, B1045 02, B1055 02

The radio detects a short to ground on the specified audio (+) or (-) circuit.

B1025 04, B1035 04, B1045 04, B1055 04

The radio detects an open on the specified audio (+) or (-) circuit.

Action Taken When the DTC Sets

The radio continues to send the output signal to the speaker signal circuit with the current fault.

Conditions for Clearing the DTC

  • A current DTC clears when the conditions for setting the DTC are no longer present and the ignition has been cycled from OFF to ON.
  • A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

  • Improper speaker mounting or loose trim may cause an audible buzz or distortion. Inspect the appropriate speaker and the surrounding interior trim for proper and secure mounting. If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.
  • When equipped with an amplifier, the radio does not set DTCs for the audio outputs.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, A11 Radio ON, mute OFF.
  2. Verify clear audio is heard from each speaker, adjusting fade and balance controls to test each speaker individually.

If audio is inoperative from one or more speakers, or the audio emitted is not clear.

Refer to Circuit/System Testing.

If clear audio is heard from all speakers.

  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate P19 Speaker. Ignition ON, A11 Radio ON, mute OFF.
  2. Test for 5-7 V between each audio signal circuit terminal 1 and terminal 2 and ground.

If less than 5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 7 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If between 5-7 V

  1. Test or replace the P19 Speaker.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Speaker Replacement Reference
  • Control Module References for radio replacement, programming, and setup.

DTC B125A: Antenna signal circuit

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B125A 02

Antenna Signal Circuit Short to Ground

DTC B125A 04

Antenna Signal Circuit Open Circuit

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The multi-band antenna is located on the roof of the vehicle. The radio antenna is enabled when the radio is turned on. The radio provides battery voltage to the antenna using the center conductor of the antenna coaxial cable. When a 12 V signal is seen on the center conductor of the antenna coax, both AM and FM signals are amplified.

Conditions for Running the DTC

  • Ignition ON.
  • Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

B125A 02

The radio detects a short to ground in the antenna signal circuit center conductor.

B125A 04

The radio detects an open in the antenna signal circuit center conductor.

Action Taken When the DTC Sets

Radio reception may be poor or not available.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clears after 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, A11 Radio ON.
  2. Verify station reception is normal when tuned to several known good AM and FM stations.

If AM or FM reception is poor.

Refer to Circuit/System Testing

If reception is normal

  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the radio antenna coax cable from the A11 Radio and from the T4M Radio Antenna.
  2. Verify the antenna coax cable passes the coax cable component test. Refer to Component Testing

If the coax cable does not pass the test

Replace the antenna coax cable

If the coax cable passes the test

  1. Connect the radio antenna coax cable to the A11 Radio.
  2. Ignition ON, A11 Radio ON.
  3. Verify a test lamp illuminates between the antenna coax cable center terminal at the T4M Radio Antenna and chassis ground.

If the test lamp does not illuminate

Replace the A11 Radio.

If the test lamp illuminates

  1. Test or replace the T4M Radio Antenna.

Component Testing

CAUTION: Refer to Test Probe Caution .

NOTE: Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.

To prevent false reading when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between coax cable center terminal end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for less than 5 ohms between the coax cable outer shield end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.

If less than infinite resistance

Replace the coax cable

If infinite resistance

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Radio Antenna Base Replacement
  • Control Module References for radio replacement, programming, and setup.

DTC B125C: Satellite antenna

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B125C 01

Satellite Antenna Circuit Short to Battery

DTC B125C 02

Satellite Antenna Circuit Short to Ground

DTC B125C 04

Satellite Antenna Circuit Open

Circuit/System Description

The digital radio receiver, located inside the radio, receives digital radio information from the digital radio antenna located on the outside of the vehicle. The digital radio receiver is connected to the digital radio antenna via a shielded coax cable. The digital radio antenna contains an amplifier which is powered by the radio through the coax cable.

Conditions for Running the DTC

This DTC is run every 300 milliseconds.

Conditions for Setting the DTC

The radio detects a circuit fault in the digital radio antenna.

Action Taken When the DTC Sets

The radio displays No XM Signal or Check Antenna.

Conditions for Clearing the DTC

  • A current DTC clears when the condition for setting the DTC is no longer present.
  • A history DTC clears after 100 malfunction-free ignition cycles.

Diagnostic Aids

The digital radio antenna requires a clear line of sight to the sky to operate properly. Reception may be limited, intermittent, or unavailable inside structures.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT

CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Special Tools

EL-48028 Digital Radio Test Antenna

For equivalent regional tools, refer to Special Tools, Special Tools (MIT tool instructions).

Circuit/System Verification

  1. With the vehicle outside in an area with an unobstructed view of the southern sky, tune to XM.
  2. Verify DTC B125C is not set as current and the No XM Signal message is not displayed on the radio.

If DTC B125C is set as current or the No XM Signal message is displayed

Refer to Circuit/System Testing.

If DTC B125C is not set as current and the No XM Signal message is not displayed.

  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the digital radio antenna coax cable from the A11 Radio. Connect the EL-48028 Digital Radio Test Antenna to the radio and place on the roof of the vehicle.
  2. Ignition ON, radio tuned to XM channel 1.
  3. Verify DTC B125C is not set as current and XM reception is improved.

If DTC B125C is set as current or XM reception is not improved

Replace the A11 Radio.

If DTC B125C is not set as current and XM reception is improved

  1. Ignition OFF, disconnect the digital radio antenna coax cable from the T4G Cellular Phone, Navigation, and Digital Radio Antenna.
  2. Verify the digital radio antenna coax cable passes the coax cable component test. Refer to Component Testing.

If the coax cable does not pass the test

Replace the antenna coax cable

If the coax cable passes the test

  1. Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.

Component Testing

CAUTION: Refer to Test Probe Caution .

NOTE: Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.

To prevent false reading when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between coax cable center terminal end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for less than 5 ohms between the coax cable outer shield end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield

If less than infinite resistance

Replace the coax cable

If infinite resistance

  1. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Radio Antenna Base Replacement
  • Control Module References for radio replacement, programming, and setup.

DTC B1265: Switched 14 volt performance short to ground

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1265 02

Switched 14 Volt Performance Short to Ground

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

When the radio is on, a discrete 12 V signal is supplied on the entertainment remote enable circuit to the audio amplifier and the Color/Navigation Info Display Module (if equipped). This signal is used to control the power state of the components.

Conditions for Running the DTC

The following are conditions that must be present in order for the radio to enable diagnostics:

  • The radio is ON.
  • The system voltage is 9 -16 V

Conditions for Setting the DTC

  • The radio detects a short to ground on the entertainment remote enable circuit.
  • The above condition is present for greater than 250 ms.

Action Taken When the DTC Sets

  • The radio implements a current limiting mode and disables the output on the entertainment remote enable circuit .
  • All components connected on the entertainment remote enable circuit will be inoperative

Conditions for Clearing the DTC

  • The condition for setting the DTC no longer exists.
  • After the ignition has been OFF for a sufficient amount of time to allow the radio to enter a low power/sleep state, the radio will re-enable the output on the following ignition cycle and the DTC will become history.
  • A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

  • This DTC may be stored as a history DTC without affecting the operation of the radio/infotainment systems.
  • The radio's current limiting logic may not re-enable the output on the entertainment remote enable circuit until after the radio performs a full power-down. It may be necessary to wait 5 min between each test attempt with the key OFF and retained accessory power OFF.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, radio OFF, radio B+ fuse removed. Disconnect all of the harness connectors listed below:
  • T3 Audio Amplifier X3 (if equipped)
  • P17 Info Display Module X1 (if equipped)
  1. Install the radio B+ fuse. Ignition ON, A11 Radio ON.
  2. Verify that a test lamp illuminates between the control circuit terminals listed below and ground:
  • T3 Audio Amplifier X3 terminal 8 (if equipped)
  • P17 Info Display Module X1 terminal 6 (if equipped)

If the test lamp does not illuminate

  1. Ignition OFF. Disconnect the X1 harness at the A11 Radio.
  2. Test for infinite resistance between the control circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance.
  1. Test for less than 2 ohms in the control circuit end to end.
  • If greater than 2 ohms, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If the test lamp illuminates.

  1. Verify that DTC B1265 does NOT set as each component is connected one at a time.

If DTC B1265 sets.

Replace the module/component that was just connected

If DTC B1265 does not set.

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Driver Information Display Replacement (UAG) , Driver Information Display Replacement (UDN)
  • Control Module References for radio and amplifier replacement, programming, and setup.

DTC B1271: Theft protection active

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category

DTC Descriptor

DTC B1271 00

Theft Protection Active

Circuit/System Description

When the radio is initially installed in the vehicle, the radio receives VIN information via serial data. The radio stores a portion of the VIN and compares this sequence to the VIN information received each time the radio powers on. The VIN in the radio is a single one-time learn.

The radio theft deterrent system is intended to disable or limit radio functionality if incorrect vehicle information is received by the radio. The radio disables functionality if the VIN information received by the radio does not match the VIN information that has been learned by the radio. This DTC is generated by the module when the Theft Protection is activated.

Conditions for Running the DTC

This DTC test runs when the radio changes from OFF to ON.

Conditions for Setting the DTC

The radio has learned a correct VIN sequence and the VIN information received via serial data does NOT match the learned VIN sequence

Action Taken When the DTC Sets

  • The radio may be disabled or have limited functionality.
  • The radio display will indicate that theft protection is active.

Conditions for Clearing the DTC

The radio receives the correct VIN information via serial data.

Diagnostic Aids

A possible cause of incorrect VIN info could be the radio was originally installed in another vehicle.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool informati

Circuit/System Verification

  1. Ignition ON, A11 Radio ON.
  2. Verify DTC B1271 is not set.

If DTC B1271 is set

Replace the A11 Radio.

If DTC B1271 is not set

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Radio replacement, programming, and setup

DTC B1287: AMPLIFIER CONTROL SIGNAL

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B1287 01

Amplifier Control Signal Circuit Short to Battery

DTC B1287 02

Amplifier Control Signal Circuit Short to Ground

DTC B1287 04

Amplifier Control Signal Circuit Open

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The radio amplifier control circuit provides varying pulse width modulated (PWM) signals to control overall muting of the amplifier. The PWM signals are varying duty cycle percentages ranging from 0-100 percent. A low duty cycle unmutes all amplifier channels and a high duty cycle mutes all amplifier channels. The amplifier control circuit will measure less than 1 V when the mute function is OFF, and approximately 8 V when at full mute. The radio monitors the amp control circuit for faults.

Conditions for Running the DTC

  • The radio is on.
  • The system voltage is 9-16 V.
  • The radio performs the test once during wakeup.

Conditions for Setting the DTC

The radio detects a fault on the amplifier control circuit 400 ms after radio activates the remote enable circuit.

Action Taken When the DTC Sets

Radio sets the DTC and continues to output correct state.

Conditions for Clearing the DTC

  • The condition must no longer be present.
  • A history DTC clears after 50 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

NOTE: To prevent misdiagnosis, the door chime must be OFF during testing.

Ensure the driver door latch is closed during testing.

  1. Ignition OFF, disconnect the X3 harness connector at the T3 Amplifier. Ignition ON, A11 Radio ON, mute ON.
  2. Test for 7.5-8.5 V between the control circuit terminal 11 and ground.

If greater than 8.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the control circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If less than 7.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the control circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the control circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If between 7.5-8.5 V

  1. A11 Radio ON, mute OFF.
  2. Test for less than 1 V between the control circuit terminal 11 and ground.

If 1 V or greater

Replace the A11 Radio.

If less than 1 V

  1. Test or replace the T3 Amplifier

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio and amplifier replacement, programming, and setup.

DTC B1446 OR B1447: Backup power source

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category

DTC Descriptors

DTC B1446

Replace Backup Power Source Below Minimum Threshold

DTC B1447

Backup Power Source Open Circuit

For symptom byte information refer to Symptom Byte List

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The backup power source provides voltage to the telematics communication interface control module , to be able to successfully place a call in the event of a main battery disconnect during a collision event.

Conditions for Running the DTC

B1446 03

  • Ignition is ON.
  • System voltage is between 9.5 and 15.5 V.
  • DTC B1447 is not set.

B1447 04

  • Ignition is ON.
  • System voltage is between 9.5 and 15.5 V.
  • The above conditions are present for greater than 10 s.

Conditions for Setting the DTC

B1446 03

The telematics communication interface control module detects that the backup power source voltage has dropped below the minimum threshold value.

B1447 04

The telematics communication interface control module detects no voltage from the backup power source.

Action Taken When the DTC Sets

B1446 03

The OnStar status LED turns red.

B1447 04

  • The OnStar status LED turns red.
  • The telematics communication interface control module will be unable to place a call in the event of a main battery disconnect during a collision event.

Conditions for Clearing the DTC

  • A current DTC B1446 will clear when the telematics communication interface control module detects the voltage of the backup power source is above the minimum threshold value.
  • A current DTC B1447 will clear when the telematics communication interface control module detects voltage from the backup power source.
  • A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

  • Shorting the backup power source positive voltage circuit to the backup power source ground circuit or chassis ground will activate the internal circuit protection of the backup power source, rendering the backup power source inoperative.
  • DTC B1447 may set if the K73 Telematics Communication Interface Control Module has been incorrectly disconnected or serviced. When disconnecting the K73 Telematics Communication Interface Control Module , disconnect the harness connector X1 at the K73 Telematics Communication Interface Control Module prior to disconnecting any other harness connectors. This will ensure the backup power source is preserved when voltage is removed from the K73 Telematics Communication Interface Control Module .

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Testing for Intermittent Conditions and Poor Connections
  • Circuit Testing
  • Wiring Repairs
  • Connector Repairs

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for greater than 9.5 V between the B+ circuit terminal 14 and the low reference circuit terminal 13.

If 9.5 V or less

Test or replace the C3 Telematics Communication Interface Control Module Battery.

If greater than 9.5 V

  1. Replace the K73 Telematics Communication Interface Control Module .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Communication Interface Module Battery Replacement (Encore), Communication Interface Module Battery Replacement (Encore)
  • Control Module References for telematics communication interface control module replacement, programming and setup.

DTC B2455 (ONSTAR): Cellular phone microphone

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category

DTC Descriptors

DTC B2455 02

Cellular Phone Microphone Circuit Short to Ground

DTC B2455 04

Cellular Phone Microphone Circuit Open/High Resistance

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The telematics communication interface control module provides the cellular phone microphone with a supplied voltage on the cellular phone microphone high signal circuit. When the microphone is in use, voice data from the user is sent back to the telematics communication interface control module on the microphone low signal circuit.

Conditions for Running the DTC

  • The ignition must be in the RUN or ACC position.
  • The system voltage is at least 9.5 V and no more than 15.5 V.
  • All the above conditions are present for greater than 10 s.

Conditions for Setting the DTC

B2455 02

The telematics communication interface control module detects an short to ground in the cellular phone microphone high signal circuit for 10 s or greater.

B2455 04

The following conditions will set this DTC:

  • The telematics communication interface control module detects an open/high resistance in the cellular phone microphone high signal circuit for 10 s or greater.
  • The telematics communication interface control module detects an open/high resistance in the microphone low signal circuit for 10 s or greater.

Action Taken When the DTC Sets

  • The OnStar status LED turns red.
  • The telematics communication interface control module will not receive a signal from the cellular phone microphone.
  • Calls can be placed but the caller cannot be heard.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the B24 Cellular Phone Microphone, ignition ON.
  2. Test for 8.0-10.5 V between the signal circuit terminal B and ground.

If less than 8.0 V

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the vehicle K73 Telematics Communication Interface Control Module.

If greater than 10.5 V

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.

If between 8.0-10.5 V

  1. Test for less than 1 V between the signal circuit terminal A and ground.

If greater than 1 V

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage in the circuit.
  • If less than 1 V, repair the K73 Telematics Communication Interface Control Module.

If less than 1 V

  1. Test for greater than 8 V between the signal circuit terminal B and the signal circuit terminal A.

If less than 8 V

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the low signal circuit and ground.
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the vehicle K73 Telematics Communication Interface Control Module.

If greater than 8 V

  1. Test or replace the B24 Cellular Phone Microphone.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Mobile Telephone Microphone Replacement (Encore), Mobile Telephone Microphone Replacement (Encore)
  • Control Module References for telematics communication interface control module replacement, programming and setup.

DTC B2455 (RADIO): Cellular phone microphone

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

DTC B2455 01

Cellular Phone Microphone Circuit Short to Battery

DTC B2455 02

Cellular Phone Microphone Circuit Short to Ground

DTC B2455 04

Cellular Phone Microphone Circuit Open

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The radio provides the Cellular Phone Microphone with a supplied voltage on the Cellular Phone microphone high signal circuit. When the Microphone is in use, voice data from the user is sent back to the radio on the microphone low signal circuit.

Conditions for Running the DTC

  • The ignition must be in the RUN or ACC position.
  • The system voltage is at least 9.5 V and no more than 15.5 V.
  • All the above conditions are present for greater than 10 seconds.

Conditions for Setting the DTC

B2455 01

  • The radio detects a short to voltage in the low signal circuit for 10 seconds or greater.

B2455 02

  • The radio detects a short to ground in the high signal circuit for 10 seconds or greater.

B2455 04

  • The radio detects an open/high resistance in the high signal circuit for 10 seconds or greater.
  • The radio detects an open/high resistance in the low signal circuit for 10 seconds or greater.

Action Taken When the DTC Sets

  • The radio will not receive a signal from the Cellular Phone Microphone.
  • Calls can be placed but the caller cannot be heard.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: It is necessary to have the vehicle in a quiet, open outside area where a cellular call can be successfully placed.

  1. Ignition ON.
  2. Verify that DTC B2455 is set.

If DTC B2455 is not set

All OK.

If DTC B2455 is set

  1. Verify that your voice can be heard clearly after placing a cellular call.

If your voice can not be heard clearly

Refer to Circuit/System Testing.

If your voice can be heard clearly

  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the B24 Cellular Phone Microphone, ignition ON.
  2. Test for 9.5-10.5 V between the signal circuit terminal B and ground.

If less than 9.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 10.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If between 9.5-10.5 V

  1. Ignition ON.
  2. Test for less than 1 V between the signal circuit terminal A and ground.

If greater than 1 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage in the circuit.
  • If less than 1 V, replace the A11 Radio.

If less than 1 V

  1. Test for 9.5-10.5 V between the signal circuit terminal B and the signal circuit terminal A.

If less than 9.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the signal circuit terminal A and ground.
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit terminal A end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the vehicle A11 Radio.

If greater than 10.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
  2. Test for less than 1 V between the signal circuit terminal A and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If between 9.5-10.5 V

  1. Test or replace the B24 Cellular Phone Microphone.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Mobile Telephone Microphone Replacement (Encore), Mobile Telephone Microphone Replacement (Encore)
  • Control Module References for Radio replacement, programming and setup.

DTC B2462: Global positioning system

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B2462 01

Global Positioning System Short to Battery

DTC B2462 02

Global Positioning System Short to Ground

DTC B2462 04

Global Positioning System Open

Circuit/System Description

The navigation antenna is connected to the telematics communication interface control module and the radio through the navigation signal splitter. The navigation signal splitter distributes the navigation signal to both the telematics communication interface control module and the navigation radio. The telematics communication interface control module supplies 5 V through the coax cable to power the internal antenna amplifier through the signal splitter. The radio supplies 5 V through the center conductor of the coax cable to power the splitter.

Conditions for Running the DTC

  • Radio On.
  • System voltage is greater than 9 V and less than 16 V.
  • The navigation radio tests the GPS antenna every 10 seconds

Conditions for Setting the DTC

B2462 01

The navigation radio detects a short to B+ on the GPS antenna signal circuit.

B2462 02

The navigation radio detects a short to ground on the GPS antenna signal circuit.

B2462 04

The navigation radio detects an open/high resistance on the GPS antenna signal circuit.

Action Taken When the DTC Sets

  • The radio uses the last reported position and the vehicle speed signal to calculate the vehicle position.
  • Route guidance may be inaccurate.
  • Turn by turn navigation may be inaccurate or inoperative.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Diagnostic Aids

  • This DTC can only be retrieved from the radio. The telematics communication interface control module does not set this DTC.
  • The radio only monitors the connection between the navigation signal splitter and the radio. The radio cannot detect faults between the signal splitter and the navigation antenna. Faults between the signal splitter and the navigation antenna will result in a loss of GPS signal without setting DTC B2462.
  • The navigation antenna requires a clear line of sight to the sky to operate properly. The GPS may have limited, intermittent, or no reception near tall buildings or inside structures.

Reference Information

Schematic Reference

  • OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)
  • Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

  • OnStar Description and Operation
  • Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-49903 OnStar Antenna Diagnostic Tool Kit

Circuit/System Testing

  1. Ignition OFF, disconnect the navigation antenna coax cable connector at the A11 Radio. Connect the EL- 49903 GM OnStar antenna diagnostic tool kit to the A11 Radio, place the test antenna on the roof of the vehicle.
  2. Ignition ON, radio ON, navigation selected.
  3. Verify DTC B2462 is not set.

If DTC B2462 is set

Replace the A11 Radio

If DTC B2462 is not set

  1. Ignition OFF, disconnect the radio navigation coax cable at the T15 Navigation Antenna Signal Splitter.
  2. Verify the radio navigation coax cable passes the coax cable component test. Refer to Component Testing.

If the coax cable does not pass the test

Replace the coax cable

If the coax cable passes the test

  1. Test or replace the T15 Navigation Antenna Signal Splitter.

Component Testing

CAUTION: Refer to Test Probe Caution .

NOTE: Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.

To prevent false reading when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between coax cable center terminal end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for less than 5 ohms between the coax cable outer shield end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.

If less than infinite resistance

Replace the coax cable

If infinite resistance

  1. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Navigation Signal Splitter Replacement (Encore)
  • Control Module References for radio replacement, programming, and setup.

DTC B2470: Cellular phone antenna

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category

DTC Descriptors

DTC B2470 02

Cellular Phone Antenna Circuit Malfunction Short to Ground

DTC B2470 04

Cellular Phone Antenna Circuit Malfunction Open Circuit

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The cellular phone and navigation antenna is connected to the telematics communication interface control module. This module supplies 5 V to the cellular phone and navigation antenna to power the internal amplifier.

When the vehicle is equipped with the optional navigation radio, a navigation antenna signal splitter is installed to distribute the GPS signal to both the telematics communication interface control module and the navigation radio. The navigation radio supplies 5 V through the GPS antenna coaxial cable to the navigation antenna signal splitter to power the internal navigation radio signal amplifier.

Conditions for Running the DTC

  • Ignition in the RUN or ACC position.
  • System voltage is between 9.5 volts and 15.5 volts.
  • The above conditions are present for greater than 1 s.

Conditions for Setting the DTC

  • The telematics communication interface control module does not detect the presence of a cellular antenna.
  • The above conditions are present for greater than 1 s.

Action Taken When the DTC Sets

  • The vehicle is unable to connect to the OnStar Call Center.
  • The OnStar status LED turns red.

Conditions for Clearing the DTC

  • The telematics communication interface control module detects the presence of a cellular antenna.
  • A history DTC clears after 50 malfunction-free ignition cycles.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-49903 GM OnStar Antenna Diagnostic Tool Kit

Circuit/System Testing

NOTE:

  • The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.
  • The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 minutes after turning the ignition ON for the GPS satellites to acquire vehicle signal.

Without Navigation Radio

  1. Ignition OFF and all vehicle systems OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 min for all vehicle systems to power down.
  2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 GM OnStar antenna diagnostic tool kit to the K73 Telematics Communication Interface Control Module.

    Place the test antenna on the roof of the vehicle, ignition ON.

  3. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
  • If the DTC sets

Replace the K73 Telematics Communications Interface Control Module.

  • If the DTC does not set
  1. Ignition OFF.
  2. Disconnect the EL-49903 GM OnStar antenna diagnostic tool kit from the K73 Telematics Communication Interface Control Module
  3. Test the coax cable. Refer to Component Testing.

If the coax cable does not pass the test

Replace the coax cable.

If the coax cable passes the test

  1. Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.

With Navigation Radio

  1. Ignition OFF and all vehicle systems OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 min for all vehicle systems to power down.
  2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 GM OnStar antenna diagnostic tool kit to the K73 Telematics Communication Interface Control Module.

    Place the test antenna on the roof of the vehicle, ignition ON.

  3. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC

If the DTC sets

Replace the K73 Telematics Communication Interface Control Module.

If the DTC does not set

  1. Ignition OFF.
  2. Disconnect the EL-49903 GM OnStar antenna diagnostic tool kit from the K73 Telematics Communication Interface Control Module
  3. Connect the coax cable to the K73 Telematics Communications Interface Control Module and disconnect the coax cable from the T15 Navigation Antenna Signal Splitter, ignition ON.
  4. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.

If less than 4.5 V

  1. Ignition OFF.
  2. Test the coax cable. Refer to Component Testing.
  • If the coax cable does not pass the test, replace the coax cable.
  • If the coax cable passes the test, test or replace the K73 Telematics Communications Interface Control Module.

If greater than 5.5 V

  1. Ignition OFF.
  2. Test the coax cable. Refer to Component Testing.
  • If the coax cable does not pass the test, replace the coax cable.
  • If the coax cable passes the test, test or replace the K73 Telematics Communications Interface Control Module.

If between 4.5-5.5 V

  1. Ignition OFF, connect the coax cable to the T15 Navigation Antenna Signal Splitter and disconnect the coax cable from the T4G Cellular Phone, Navigation, and Digital Radio Antenna, ignition ON.
  2. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.

If less than 4.5 V

  1. Ignition OFF.
  2. Test the coax cable. Refer to Component Testing.
  • If the coax cable does not pass the test, replace the coax cable.
  • If the coax cable passes the test, test or replace the T15 Navigation Antenna Signal Splitter.

If greater than 5.5 V

  1. Ignition OFF.
  2. Test the coax cable. Refer to Component Testing.
  • If the coax cable does not pass the test, replace the coax cable.
  • If the coax cable passes the test, test or replace the T15 Navigation Antenna Signal Splitter.

If between 4.5-5.5 V

  1. Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.

Component Testing

CAUTION: Refer to Test Probe Caution

NOTE:

  • Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.
  • To prevent false readings when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between the coax cable center terminal end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for greater than 5 ohms between the coax cable outer shield end to end.

If 5 ohms or greater

Replace the coax cable.

If less than 5 ohms

  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.

If less than infinite resistance

Replace the coax cable.

If infinite resistance

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Radio Antenna Base Replacement
  • Control Module References for Telematics Communication Interface Control Module replacement, programming and setup.

DTC B2476 OR B2482: Cellular phone select service switch

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B2476 04

Cellular Phone Select Service Switch Open

DTC B2476 59

Cellular Phone Select Service Switch Protection Time-out

DTC B2482 00

Cellular Phone Select Service Switch Range/Performance

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The OnStar button assembly consists of 3 buttons: Call/Answer, OnStar Call Center, and OnStar Emergency. The telematics communication interface control module supplies the OnStar button assembly with 10 V via the 10 V reference circuit . Each of the buttons, when pressed, completes the circuit across a resistor allowing a specific voltage to be returned to the telematics communication interface control module over the keypad signal circuit. Depending upon the voltage range returned, the telematics communication interface control module is able to identify which button has been pressed.

Conditions for Running the DTC

  • Ignition ON.
  • Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

B2476 04

The telematics communication interface control module detects a short to voltage or an open/high resistance on the keypad 10 V reference circuit.

B2482 and B2476 59

The telematics communication interface control module detects a valid signal on the keypad signal circuit for longer than 15 s. If one of the OnStar buttons is held or stuck for 15 s or greater, the telematics communication interface control module will set this DTC.

Action Taken When the DTC Sets

  • The OnStar status LED turns red.
  • No calls can be placed.
  • The telematics communication interface control module will ignore all inputs from the OnStar button assembly.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: Contact the OnStar Call Center first before pressing the emergency button in order to notify them of the test.

  1. Ignition ON.
  2. Verify that each button of the S51 Telematics Button Assembly operates normally by pressing each button individually.

If none of the buttons operate normally

Refer to Circuit/System testing

If some, but not all, of the buttons operate normally

Test or replace the A10 Inside Rearview Mirror

If all of the buttons operate normally

  1. All OK.

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A10 Inside Rearview Mirror. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

  1. Ignition ON.
  2. Test for 8.0-10.5 V between the 10 V reference circuit terminal 4 and ground.

If less than 8.0 V

  1. Ignition OFF, disconnect the harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the 10 V reference circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the 10 V reference circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the K73 Telematics Communication Interface Control Module.

If greater than 10.5 V

  1. Ignition OFF, disconnect the harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the 10 V reference circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.

If between 8.0-10.5 V

  1. Ignition OFF.
  2. Test for 500-900 ohms between the signal circuit terminal 3 and ground.

If less than 500 ohms

  1. Disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the K73 Telematics Communication Interface Control Module

If greater than 900 ohms

  1. Disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V
  1. Ignition OFF.
  2. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the K73 Telematics Communication Interface Control Module.

If between 500-900 ohms

  1. Test or replace the A10 Inside Rearview Mirror.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair procedure.

  • Inside Rearview Mirror Replacement
  • Control Module References for telematics communication interface control module replacement, programming, and setup.

DTC B2485: Wireless communication (BT) antenna

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

DTC B2485 02

Wireless Communication (BT) Antenna Circuit Short to Ground

DTC B2485 04

Wireless Communication (BT) Antenna Circuit Open

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The operating range of the signal is approximately 30 feet.

The Bluetooth antenna is a small fixed antenna connected directly to the telematics communication interface control module and is used to send and receive signals from a Bluetooth enabled cellular phone.

Conditions for Running the DTC

  • The ignition is in OFF, ACCESSORY or RUN position.
  • The system voltage is between 9-16 V.
  • The telematics communication interface control module tests the antenna once every second.

Conditions for Setting the DTC

B2485 02

  • The signal voltage is less than 1 V.
  • The above conditions must be met for 500 ms.

B2485 04

  • The signal voltage is greater than 2 V.
  • The above conditions must be met for 500 ms.

Actions Taken When the DTC Sets

  • The OnStar status LED turns red.
  • Bluetooth functionality is disabled.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Diagnostic Aids

Verify the mobile device is properly configured for the feature being used. Refer to the device manufacturers information.

  • Verify the function/feature that is being used is supported by the mobile device.
  • The device must be paired to the telematics communication interface control module to use the available Bluetooth feature(s). The pairing process must only be performed once for each device, unless that device's information is deleted.
  • The system can store pairing information for multiple devices, but can only be actively connected to one at any given time.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Special Tools

EL-50334-20 Multi-Media Interface Tester (Multi-Media Interface Tool)

Circuit/System Testing

  1. Verify that the T4S Wireless Communication Antenna - Bluetooth is properly connected to the K73 Telematics Communication Interface Control Module and is not damaged.

If the antenna is disconnected

Connect the T4S Wireless Communication Antenna - Bluetooth to the module.

If the antenna is damaged

Test or replace the T4S Wireless Communication Antenna - Bluetooth .

  • If the antenna is connected and not damaged

NOTE: The Multi-Media Interface Tool tool can be used to test either cellular phone or streaming audio functions. Refer to the tool instructions, and perform the appropriate test(s) related to the customers concern in the following steps.

  1. Ignition ON, infotainment system ON.
  2. Verify the infotainment system successfully pairs with the Multi-Media Interface Tool.

If the infotainment system does not successfully pair with the Multi-Media Interface Tool.

  1. Test or replace the T4S Wireless Communication Antenna - Bluetooth .
  2. Clear the DTC, ignition OFF.
  3. Ignition ON.
  4. Verify the DTC is not set.
  • If the DTC is set, replace the K73 Telematics Communication Interface Control Module.
  • If the DTC is not set
  1. All OK.

If the infotainment system successfully pairs with the Multi-Media Interface Tool.

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for telematics communication interface control module replacement, programming and setup.

DTC U0255-U0257: Lost communication with info display

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC U0255

Lost Communication with Info Display Module

DTC U0256

Lost Communication with Infotainment Faceplate Control Module

DTC U0257

Lost Communication with Info Display Module/Infotainment Faceplate Control Module

Circuit/System Description

The radio information display and controls are separate components from the radio. One or more configurations may be possible, dependent upon the available content for the vehicle. The DTC(s) that can set when a malfunction occurs can vary due to calibration differences required for the vehicle content.

Diagnosis of these communication DTCs is based upon the symptom observed in the vehicle.

Monochrome Displays

When the vehicle is equipped with a monochrome display, the radio and the display communicate with each other via CGI serial data. The radio controls communicate with the display via LIN communications, and the control messages are passed through to the radio.

When the display and controls are combined in an assembly, the communication between the two components occurs within the assembly. If the two components are separate, the communication between the display and the controls is external, via the wiring harness.

Color Displays

When the vehicle is equipped with a color display, the display and controls communicate individually with the radio. The radio communicates directly with the controls via CGI serial data. A dedicated video cable is used to communicate graphical information between the radio and the display.

For non-touch color displays, a dedicated dimming circuit is used. The radio provides an output to the display based on dimming level information the radio receives.

Touch screen color displays use touch serial data communication between the display and the radio to exchange touch data, backlighting, and dimming levels.

Diagnostic Aids

  • When equipped with a monochrome display, if the display is inoperative, the main radio controls will also be inoperative.
  • The functions available on the steering wheel controls (if equipped) will continue to operate if the main radio controls are inoperative.
  • The DTC may be stored as a history DTC without affecting the operation of the display or controls.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, A11 Radio ON.
  2. Verify the P17 Info Display Module turns on and information is shown on the display.

If the P17 Info Display Module does not turn on, or information is not shown in the display.

  • If the P17 Info Display Module turns on and information is shown on the display.
  1. Verify that all radio controls operate and perform the correct function.
  • If some, but not all, controls operate normally.

Replace the appropriate A20 Radio/HVAC Controls or the A22 Radio Controls.

  • If all controls are inoperative.

Refer to Radio Controls Malfunction (Monochrome Display), Radio Controls Malfunction (Color Display).

  • If all controls operate and perform the correct function.
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Control Module References for replacement, programming, and setup.

SYMPTOMS - CELLULAR COMMUNICATION

NOTE: The following steps must be completed before using the symptom table

  1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:
  • There are no DTCs set.
  • The control modules can communicate via the serial data link.
  1. Review the system operation in order to familiarize yourself with the system functions. Refer to OnStar Description and Operation.

Visual/Physical Inspection

  • Inspect for aftermarket devices which could affect the operation of the Radio/Audio System. Refer to Checking Aftermarket Accessories .
  • Inspect for easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

  • Bluetooth Malfunction (OnStar), Bluetooth Malfunction (Radio - Without UH7), Bluetooth Malfunction (Radio - With UH7)
  • No Global Positioning System (GPS) Reception
  • OnStar Microphone Malfunction
  • OnStar Audio Malfunction
  • OnStar Button LED Malfunction
  • OnStar Call Center Remote Function Requests Malfunction
  • OnStar Button Malfunction
  • Unable to Contact OnStar Call Center
  • OnStar Voice Recognition Malfunction
  • OnStar Steering Wheel Control Functions Malfunction

SYMPTOMS - ENTERTAINMENT

IMPORTANT: The following steps must be completed before using the symptom table.

  1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:
  • There are no DTCs set.
  • The control modules can communicate via the serial data link.
  1. Review the system operation in order to familiarize yourself with the system functions. Refer to Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display).

Visual/Physical Inspection

  • Inspect for aftermarket devices which could affect the operation of the Radio/Audio System. Refer to Checking Aftermarket Accessories .
  • Inspect for easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

  • Application Malfunction
  • Auxiliary Audio Input Malfunction
  • Bluetooth Malfunction (OnStar), Bluetooth Malfunction (Radio - Without UH7), Bluetooth Malfunction (Radio - With UH7)
  • Digital Radio Poor or No Reception
  • Navigation System - Voice Recognition Malfunction
  • No Global Positioning System (GPS) Reception
  • Radio Controls Malfunction (Monochrome Display), Radio Controls Malfunction (Color Display)
  • Radio Information Display Malfunction (Monochrome Display), Radio Information Display Malfunction (Color Display)
  • Radio Poor Reception
  • Speaker Malfunction

SYMPTOMS - ENTERTAINMENT

IMPORTANT: The following steps must be completed before using the symptom table.

  1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:
  • There are no DTCs set.
  • The control modules can communicate via the serial data link.
  1. Review the system operation in order to familiarize yourself with the system functions. Refer to Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display).

Visual/Physical Inspection

  • Inspect for aftermarket devices which could affect the operation of the Radio/Audio System. Refer to Checking Aftermarket Accessories .
  • Inspect for easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

fer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

  • Application Malfunction
  • Auxiliary Audio Input Malfunction
  • Bluetooth Malfunction (OnStar), Bluetooth Malfunction (Radio - Without UH7), Bluetooth Malfunction (Radio - With UH7)
  • Digital Radio Poor or No Reception
  • Radio Controls Malfunction (Monochrome Display), Radio Controls Malfunction (Color Display)
  • Radio Information Display Malfunction (Monochrome Display), Radio Information Display Malfunction (Color Display)
  • Radio Poor Reception
  • Speaker Malfunction

APPLICATION MALFUNCTION

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Circuit/System Description

The term application refers to any piece of software that works on a system (hardware) that is being operated by its own software. Applications are typically small software programs which uses the hardware to perform a specific task, as opposed to operating the entire system.

Diagnostic Aids

  • For an application to be used, it must be installed on both the vehicle infotainment system and a compatible mobile device.
  • The application must work correctly on the device to work with the vehicle infotainment system.
  • The user may be required to log-in to the application on the mobile device before using the application from the vehicle controls.
  • Applications use the mobile device and connection to a service provider to operate. Connection quality issues, or service provider data transmission issues can give the appearance of a vehicle malfunction.
  • The device must be connected to the system. This may be done wirelessly via Bluetooth , or via the vehicle USB port.

When a mobile device is connected via Bluetooth, some or all of the device controls may be unavailable from the radio controls. This varies dependant upon the device being used. Refer to the vehicle owners manual, supplements, and the device manufacturers information for information on devices, control, and operation.

Refer to the device manufacturers information for the preferred connection method.

  • The device must be unlocked, and any additional applications should be closed.
  • If the device has any sound enhancement features such as noise reduction or echo control, these features should be turned off.
  • A low battery condition in the mobile device may not allow the device to connect to the system, or can create communication issues with the device. Verify the device battery state of charge and re-charge or replace as needed.
  • If a 'Please See Device' or similar type error message is displayed, this may indicate the device has lost its connection to the vehicle, or the device has lost its external data connection.
  • If a cable is used for connection, attempt to connect the device using a different cable; cables can deteriorate over time or become damaged.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Verify the application is installed on the mobile device and is up to date.
  • If the application is not installed or is not up to date.

Install or update the application on the device.

  • If the application is installed on the mobile device and is up to date
  1. Verify the application operates correctly on the mobile device.
  • If the application is not operating correctly on the mobile device.

Refer to the application website.

  • If the application is operating correctly on the mobile device.
  1. Verify the A11 Radio calibrations are current.
  • If the radio calibrations are not current

Reprogram the A11 Radio and re-evaluate the concern.

  • If no update calibrations are available
  1. Verify the application is installed on the A11 Radio and is up to date.
  • If the application is not installed or is not up to date.

Install or update the application on the A11 Radio.

  • If the application is installed on the A11 Radio and is up to date
  1. Ignition ON, A11 Radio ON.
  2. Verify the mobile device can connect to the infotainment system. Refer to the owners manual for information on the preferred connection method for the device.

If the mobile device cannot connect to the vehicle infotainment system.

  • If unable to connect via Bluetooth, refer to Bluetooth Malfunction (OnStar), Bluetooth Malfunction (Radio - Without UH7), Bluetooth Malfunction (Radio - With UH7).
  • If unable to connect via USB, refer to Auxiliary Audio Input Malfunction.

If the mobile device connects to the vehicle infotainment system.

  1. Launch the application.
  2. Verify the applications operates properly with the vehicle infotainment system.
  • If the application does not function properly

Refer to diagnostic aids.

  • If the application functions properly
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio replacement, programming, and setup.

Auxiliary audio input malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

Auxiliary Audio Input Jack

The 3.5 mm (1/8 in.) auxiliary audio input jack is located in the console. All circuits from the auxiliary jack are connected directly to the radio. When a device is connected to the auxiliary jack an internal switch opens. The radio detects the device and switches to AUX as the audio source. Audio signals from the device are sent to the radio from the auxiliary input jack via the left, right, and common audio signal circuits.

USB Port

The vehicle may be equipped with a USB port in the console. This port allows USB connectivity to the infotainment system from portable media players or a USB storage device (memory stick/flash drive). When a device is connected to the USB port, the system detects the device and switches to USB as the audio source.

Once connected, the device can be controlled from the radio controls.

The USB port is connected to the radio via a standard USB cable. Mini type USB connectors are used to connect the cable at the USB port and at the radio or multimedia player interface module. Standard USB male to female connections are typically used for connecting USB cables together where an in-line connection is required. An in-line cable connection is typically found between the console and I/P harness.

Not all portable media player devices are compatible. Refer to the owner's manual for information on USB devices, control, and operation.

Diagnostic Aids

Auxiliary Audio Input Jack

  • When a device is first connected to the 3.5 mm (1/8 in.) input jack the infotainment system automatically switches to that device. If an auxiliary device has already been connected, press the AUX or CD/AUX button to select the device.
  • If the system detects the device, but the audio is not heard or is not clear, attempt to connect the device using a different cable; cables can deteriorate over time or become damaged.
  • Playback of an audio device that is connected to the 3.5 mm jack can only be controlled using the controls on the device.
  • The volume control on the device may need to be adjusted to ensure sufficient playback volume through the infotainment system.

USB

  • When a device is first connected to the USB port, the infotainment system automatically switches to that device. If an auxiliary device has already been connected, press the AUX or CD/AUX button to select the device.
  • A low battery condition in a portable media player may not allow the device to connect to the system, or can create communication issues with the device. Verify the device battery state of charge and re-charge or replace as needed.
  • Connect the device directly to the USB port if possible. Only use a cable if it is required to connect the device. The use of extension cables can cause communication issues.
  • If a cable is required for connection, attempt to connect the device using a different cable; cables can deteriorate over time or become damaged.
  • Attempt audio playback from multiple USB devices when diagnosing USB concerns. Device compatibility can vary based on vehicle equipment. If the infotainment system is capable of operating any USB type device, the cause of the concern is not with the vehicle system. The inoperative device(s) may be incompatible or contain no recognized media types.
  • If a 'Device Not Supported' or similar type error message is displayed, this indicates the system has connected to the device but cannot communicate with it properly. This does not indicate an issue with the vehicle system. The device may be incompatible, may require a 'reset', or may require an update to its software/firmware.
  • If a 'No Supported Data Found' or similar type error message is displayed, this indicates the system has connected to the device and is communicating, but cannot find any compatible files/data. This does not indicate an issue with the vehicle system. Verify the device contains compatible media/file types.
  • Poor connections or damaged USB cables can cause intermittent or no operation of USB devices. Inspect connectors, terminals, and cables for damage and replace components as necessary. Ensure all USB inline connections and connections at components are fully seated and connector position retainers/locks are secure.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  • EL-50334-20 Multi-Media Interface Tester (MIT)
  • EL-50334-50 USB Cable and Adapter Kit

For equivalent regional tools, refer to Special Tools, Special Tools (MIT tool instructions)

Circuit/System Verification

Auxiliary Audio Input Jack

  1. Verify no DTCs are present.

If any DTCs are present

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If no DTCs are present

  1. Ignition ON, radio ON.
  2. Verify the infotainment system switches to AUX as the audio source with the EL-50334-20 Multi-Media Interface Tester (MIT) connected to the auxiliary audio input jack.

If the infotainment system does not switch to AUX as the audio source

Refer to Circuit/System Testing - Auxiliary Input Jack.

If the infotainment system switches to AUX as the audio source

  1. Verify the audio from the EL-50334-20 Multi-Media Interface Tester (MIT) is heard through the vehicle infotainment system while operating the test tool to begin audio playback.

If audio is not heard from the test tool.

Refer to Circuit/System Testing - Auxiliary Input Jack.

If audio is heard from the test tool.

  1. All OK

USB Port

  1. Verify no DTCs are present.

If any DTCs are present

Refer to Diagnostic Trouble Code (DTC) List - Vehicle

If no DTCs are present

  1. Ignition ON, radio ON.
  2. Verify the infotainment system switches to USB as the audio source with the EL-50334-20 Multi-Media Interface Tester (MIT) connected to the USB port.

If the infotainment system does not switch to USB as the audio source

Refer to Circuit/System Testing - USB Port.

If the infotainment system switches to USB as the audio source

  1. Verify the audio from the EL-50334-20 Multi-Media Interface Tester (MIT) is heard through the vehicle infotainment system while operating the system to play audio from the test tool.
  • If audio is not heard from the test tool.

Refer to Circuit/System Testing - USB Port.

  • If audio is heard from the device
  1. All OK.

Circuit/System Testing

Auxiliary Audio Input Jack

  1. Ignition OFF, disconnect the X1 harness connector at the X83 Auxiliary Audio Input. Ignition ON, radio ON.
  2. Test for 2.5-3.5 V between the signal circuit terminal 5 and ground.

If less than 2.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 3.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
  2. Test for less than 1 V between the detection circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If between 2.5-3.5 V

  1. Test for less than 1 V between the signal circuits listed below and ground:
  • Left auxiliary audio signal circuit terminal 1
  • Right auxiliary audio signal circuit terminal 2
  • Auxiliary audio common signal circuit terminal 3

If 1 V or greater

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If less than 1 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the signal circuits listed below and ground:
  • Auxiliary audio common signal circuit terminal 23
  • Left auxiliary audio signal circuit terminal 24
  • Right auxiliary audio signal circuit terminal 10
  • If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

  1. Test for less than 5 ohms between the signal circuit terminals listed below:
  • A11 Radio terminal 24 X1 and the X83 Auxiliary Audio Input terminal 1 X1
  • A11 Radio terminal 10 X1 and the X83 Auxiliary Audio Input terminal 2 X1
  • A11 Radio terminal 23 X1 and the X83 Auxiliary Audio Input terminal 3 X1
  • If 5 ohms greater

Repair the open/high resistance in the circuit.

If less than 5 ohms

  1. Replace the X83 Auxiliary Audio Input. Connect all harness connectors.
  2. Connect and operate the EL-50334-20 Multi-Media Interface Tester (MIT).
  3. Verify the audio from the test tool is heard through the vehicle infotainment system.

If audio is not heard from the test tool

Replace the A11 Radio.

If audio is heard from the test tool

  1. All OK.

USB Port

  1. Ignition OFF, disconnect the USB cable connection at the A11 Radio.

NOTE: USB cables and adapters for the following tests are found in the EL-50334- 50 USB Cable and Adapter Kit.

  1. Connect the EL-50334-1 Type A male to Mini A male USB Cable to the A11 Radio. Connect the EL- 50334-3 Type A female to Type A female adapter to the EL-50334-1 Cable.
  2. Ignition ON, radio ON, connect the EL-50334-20 Multi-Media Interface Tester (MIT) to the EL-50334-3 adapter.
  3. Verify the infotainment system switches to USB as the audio source.

If the infotainment system does not switch to USB as the audio source

Replace the A11 Radio

If the infotainment system switches to USB as the audio source

  1. Ignition OFF, connect the vehicle USB cable to the A11 Radio. Disconnect the I/P to floor console inline USB cable connector.

NOTE: The EL-50334-3 or EL-50334-4 adapter may be required for the following test.

  1. Ignition ON, radio ON, connect the EL-50334-20 Multi-Media Interface Tester (MIT) to the I/P side of the inline USB cable connector.
  2. Verify the infotainment system switches to USB as the audio source.

If the infotainment system does not switch to USB as the audio source

Replace the I/P USB cable assembly.

If the infotainment system switches to USB as the audio source

  1. Ignition OFF, connect the I/P to floor console inline USB cable connector.
  2. Disconnect the USB cable at the X83 Auxiliary Audio Input. Connect the EL-50334-4 Type A female to Mini B female adapter to the USB cable.
  3. Ignition ON, radio ON, connect the EL-50334-20 Multi-Media Interface Tester (MIT) to the EL-50334-4 adapter.
  4. Verify the infotainment system switches to USB as the audio source.

If the infotainment system does not switch to USB as the audio source

Replace the console USB cable assembly.

If the infotainment system switches to USB as the audio source

  1. Test or replace the X83 Auxiliary Audio Input.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Audio Disc Player and USB Receptacle Replacement (Encore), Audio Disc Player and USB Receptacle Replacement (Encore)
  • Control Module References for radio replacement, programming, and setup.

Bluetooth malfunction (onstar)

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Circuit/System Description

The Bluetooth antenna is internal to, or is a small fixed antenna connected directly to, the telematics communication interface control module and is used to send and receive signals from a Bluetooth enabled cellular phone. The antenna utilizes no cabling and is not external to the vehicle.

In order to use hands-free calling, the cellular phone must be paired to the vehicle. Up to five devices can be paired to the vehicle at one time, but only one can be connected at any given time. To pair a phone, the customer must know how to operate the Bluetooth functionality of their phone. The pairing process must only be done one time for each phone, unless that phone's information is deleted. For safety reasons, the pairing process is disabled while the vehicle is moving.

Diagnostic Aids

  • The purpose of this diagnostic is to verify the ability of the telematics communication interface control module to pair to a Bluetooth device.
  • Before performing this test, verify compatibility of the cellular phone(s) the customer is attempting to use with the vehicle. Based on the cellular phone's service provider and the manufacturer's implementation of Bluetooth , not all phones support all available Bluetooth functionality. A vehicle and feature compatibility list will be provided via the GM Bluetooth website
  • If the vehicle passes the following tests and a compatible device is being used, the concern may be due to a device malfunction or an incomplete/improper pairing attempt.
  • A Bluetooth test tool or equivalent can also be used to verify the ability of the customers cellular phone (s) to pair with another device.

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-50334-20 Multi-Media Interface Tester (Multi-Media Interface Tool)

Circuit/System Verification

  1. Ignition ON.
  2. Verify no DTCs are set.
  • If any DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle

  • If no DTCs are set

NOTE: The Multi-Media Interface Tool can be used to test either cellular phone or streaming audio functions. Refer to the tool instructions, and perform the appropriate test(s) related to the customers concern in the following steps.

  1. Ignition ON, infotainment system ON.
  2. Verify the infotainment system successfully pairs with the Multi-Media Interface Tool.

If the infotainment system does not successfully pair with the Multi-Media Interface Tool.

  1. Verify the vehicle is equipped with an external Bluetooth Antenna.
  • If not equipped with an external Bluetooth Antenna, replace the K73 Telematics Communication Interface Control Module
  • If equipped with an external Bluetooth Antenna
  1. Replace the Bluetooth Antenna.
  2. Verify the infotainment system successfully pairs with the Multi-Media Interface Tool.
  • If the infotainment system does not successfully pair with the Multi-Media Interface Tool, replace the K73 Telematics Communication Interface Control Module.
  • If the infotainment system successfully pairs with the Multi-Media Interface Tool.
  1. All OK.

If the infotainment system successfully pairs with the Multi-Media Interface Tool.

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair procedure.

Control Module References for telematics communication interface control module replacement, programming, and setup.

BLUETOOTH MALFUNCTION (RADIO - WITHOUT UH7)

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Circuit/System Description

Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The operating range of the signal is approximately 30 feet.

The available features and functions are determined by the type of device and the software within the devices being used. For a feature or function to operate, it must be supported in both devices.

The Bluetooth hardware is internal to the radio. The radio supports streaming of data (music, voice, information) from cellular phones and other mobile devices that support those features. The radio may also be capable of interfacing with cellular phones for hands-free features.

Refer to the vehicle owners manual, supplements, and the device manufacturers information for information on devices, control, operation. and pairing instructions.

Diagnostic Aids

  • Verify the mobile device is properly configured for the feature being used. Refer to the device manufacturers information.
  • Verify the function/feature that is being used is supported by the mobile device.
  • The device must be paired to the radio to use the available Bluetooth feature(s). The pairing process must only be performed once for each device, unless that device's information is deleted.
  • The system can store pairing information for multiple devices, but can only be actively connected to one at any given time.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-50334-20 Multi-Media Interface Tester (MIT)

For equivalent regional tools, refer to Special Tools, Special Tools (MIT tool instructions).

Circuit/System Verification

  1. Verify no DTCs are present.

If any DTCs are present

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If no DTCs are present

  1. Verify the A11 Radio calibrations are current.

If the radio calibrations are not current

Reprogram the A11 Radio and re-evaluate the concern.

If no update calibrations are available

NOTE: The MIT tool can be used to test either cellular phone or streaming audio functions. Refer to the tool instructions, and perform the appropriate test (s) related to the customers concern in the following steps.

  1. Ignition ON, infotainment system ON.
  2. Verify the infotainment system successfully pairs with the MIT tool.

If the infotainment system does not successfully pair with the MIT tool.

Replace the A11 Radio.

If the infotainment system successfully pairs with the MIT tool.

  1. Verify the infotainment system successfully completes the desired feature test using the MIT tool.

If the feature test is not successful

Replace the A11 Radio.

If the feature test is successful

  1. All OK. Refer to Diagnostic Aids.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio replacement, programming, and setup

Bluetooth malfunction (radio - with UH7)

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Circuit/System Description

Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The operating range of the signal is approximately 30 feet.

The available features and functions are determined by the type of device and the software within the devices being used. For a feature or function to operate, it must be supported in both devices.

The Bluetooth hardware is internal to the radio. The radio supports streaming of data (music, voice, information) from cellular phones and other mobile devices that support those features. The radio may also be capable of interfacing with cellular phones for hands-free features.

Refer to the vehicle owners manual, supplements, and the device manufacturers information for information on devices, control, operation, and pairing instructions.

Diagnostic Aids

  • Verify the mobile device is properly configured for the feature being used. Refer to the device manufacturers information.
  • Verify the function/feature that is being used is supported by the mobile device.
  • The device must be paired to the radio to use the available Bluetooth feature(s). The pairing process must only be performed once for each device, unless that device's information is deleted.
  • The system can store pairing information for multiple devices, but can only be actively connected to one at any given time.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Verify the radio calibrations are current.
  • If the radio calibrations are not current

Reprogram the A11 Radio and re-evaluate the concern.

  • If no update calibrations are available

NOTE: Verify the device being used for testing is capable of the Bluetooth feature(s) related to the customer concern.

  1. Ignition ON, infotainment system ON.
  2. Verify the infotainment system successfully pairs with a mobile device.

If the infotainment system does not successfully pair with a mobile device

  1. Attempt to pair another mobile device.
  • If the infotainment system cannot pair with any mobile device, replace the A11 Radio.
  • If the infotainment system successfully pairs with the mobile device
  1. The malfunction is related to the mobile device.

If the infotainment system successfully pairs with the mobile device

  1. Verify the infotainment system performs the desired feature using the mobile device.

If the feature does not function correctly

  1. Pair another mobile device.
  2. Verify the infotainment system performs the desired feature using the mobile device
  • If the infotainment system cannot perform the desired feature with any mobile device, replace the A11 Radio.
  • If the infotainment system successfully performs the desired feature.
  1. The malfunction is related to the mobile device.

If the feature functions correctly

  1. All OK. Refer to Diagnostic Aids.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio replacement, programming, and setup.

Digital radio poor or no reception

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B125C 01

Satellite Antenna Circuit Short to Battery

DTC B125C 02

Satellite Antenna Circuit Short to Ground

DTC B125C 04

Satellite Antenna Circuit Open

Circuit/System Description

The digital radio receiver, located inside the radio, receives digital radio information from the digital radio antenna located on the outside of the vehicle. The digital radio receiver is connected to the digital radio antenna via a shielded coax cable. The digital radio antenna contains an amplifier which is powered by the radio through the coax cable.

Conditions for Running the DTC

This DTC is run every 300 milliseconds.

Conditions for Setting the DTC

The radio detects a circuit fault in the digital radio antenna.

Action Taken When the DTC Sets

The radio displays No XM Signal or Check Antenna.

Conditions for Clearing the DTC

  • A current DTC clears when the condition for setting the DTC is no longer present.
  • A history DTC clears after 100 malfunction-free ignition cycles.

Diagnostic Aids

The digital radio antenna requires a clear line of sight to the sky to operate properly. Reception may be limited, intermittent, or unavailable inside structures.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Special Tools

EL-48028 Digital Radio Test Antenna

For equivalent regional tools, refer to Special Tools, Special Tools (MIT tool instructions).

Circuit/System Verification

  1. With the vehicle outside in an area with an unobstructed view of the southern sky, tune to XM.
  2. Verify DTC B125C is not set as current and the No XM Signal message is not displayed on the radio.

If DTC B125C is set as current or the No XM Signal message is displayed.

Refer to Circuit/System Testing.

If DTC B125C is not set as current and the No XM Signal message is not displayed.

  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the digital radio antenna coax cable from the A11 Radio. Connect the EL-48028 Digital Radio Test Antenna to the radio and place on the roof of the vehicle.
  2. Ignition ON, radio tuned to XM channel 1.
  3. Verify DTC B125C is not set as current and XM reception is improved.

If DTC B125C is set as current or XM reception is not improved

Replace the A11 Radio.

If DTC B125C is not set as current and XM reception is improved

  1. Ignition OFF, disconnect the digital radio antenna coax cable from the T4G Cellular Phone, Navigation, and Digital Radio Antenna.
  2. Verify the digital radio antenna coax cable passes the coax cable component test. Refer to Component Testing.

If the coax cable does not pass the test

Replace the antenna coax cable

If the coax cable passes the test

  1. Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna

Component Testing

CAUTION: Refer to Test Probe Caution .

NOTE: Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.

To prevent false reading when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between coax cable center terminal end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for less than 5 ohms between the coax cable outer shield end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.

If less than infinite resistance

Replace the coax cable

If infinite resistance

  1. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Radio Antenna Base Replacement
  • Control Module References for radio replacement, programming, and setup.

Onstar microphone malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The telematics communication interface control module provides the Cellular Phone Microphone with a supplied voltage on the cellular phone microphone signal circuit. When the cellular phone microphone is in use, voice data from the user is sent back to the telematics communication interface control module on the signal circuit.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON.
  2. Verify that DTC B2455 is not set.

If DTC B2455 is set

Refer to DTC B2455 (OnStar), DTC B2455 (Radio).

If DTC B2455 is not set

  1. Verify that a successful OnStar voice command can be made.

If your voice can not be heard clearly.

Refer to Circuit/System Testing - Microphone Malfunction.

If your voice can be heard clearly

  1. All OK.

Circuit/System Testing

Microphone Malfunction

  1. Ignition OFF, disconnect the harness connector at the B24 Cellular Phone Microphone, ignition ON.
  2. Test for 8.0-10.5 V between the signal circuit terminal B and ground.

If less than 8.0 V

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the vehicle K73 Telematics Communication Interface Control Module.

If greater than 10.5 V

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.

If between 8.0-10.5 V

  1. Test for less than 1 V between the signal circuit terminal A and ground.

If greater than 1 V

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage in the circuit.
  • If less than 1 V, repair the K73 Telematics Communication Interface Control Module.

If less than 1 V

  1. Test for greater than 8 V between the signal circuit terminal B and the signal circuit terminal A.
  • If less than 8 V
  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the vehicle K73 Telematics Communication Interface Control Module.

If greater than 9 V

  1. Test or replace the B24 Cellular Phone Microphone.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair procedure.

  • Mobile Telephone Microphone Replacement (Encore), Mobile Telephone Microphone Replacement (Encore)
  • Control Module References for radio or telematics communication interface control module replacement, programming, and setup.

Navigation system - voice recognition malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

When voice recognition for the navigation equipped infotainment system is started, voice signals from the cellular phone microphone are passed through the telematics communication interface control module to the radio via the voice recognition audio circuits.

Diagnostic Aids

  • Refer to the Navigation System Owners Manual for voice recognition use and commands.
  • Navigation voice commands are not available until the OK button has been selected.
  • If the radio is off, the only commands available will be Hands Free and Help.
  • When the system recognizes the command the system will either perform the function or ask to confirm the choice by clearly saying "yes" or "no".
  • If experiencing difficulty with the system recognizing a command, confirm that the command is correct.
  • Background noise such as a climate control fan positioned on high, open windows, or very loud outside noises, can cause voice commands to be misunderstood.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Verify the OnStar voice recognition system is operating normally.
  • If the OnStar voice recognition system is not operating normally.

Refer to OnStar Voice Recognition Malfunction.

  • If the OnStar voice recognition system is operating normally.
  1. Ignition ON, radio ON.

NOTE: Refer to the Navigation System Owners Manual for voice recognition use and commands.

  1. Begin voice recognition for the radio and clearly speak one of the available commands.
  2. Verify the infotainment system responds correctly to the command.
  • If the infotainment system does not respond correctly to the command.
  1. Clearly speak a different command.
  2. Verify the infotainment system responds correctly to the command.
  • If the infotainment system does not respond correctly to any commands, refer to Circuit/System Testing.
  • If the infotainment system responds correctly to the command.
  1. Refer to the navigation system owners manual for hints on speaking commands.

If the infotainment system responds correctly to the command.

  1. All OK

Circuit/System Testing

  1. Ignition OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module and the X4 harness connector at the A11 Radio.
  2. Ignition ON.
  3. Test for less than 1 V between the signal circuits listed below and ground:
  • voice recognition signal circuit A11 Radio X4 terminal 6
  • voice recognition low reference circuit A11 Radio X4 terminal 16

If 1 V greater

Repair the short to voltage on the circuit.

If less than 1 V

  1. Ignition OFF.
  2. Test for infinite resistance between the circuits listed below and ground:
  • voice recognition signal circuit A11 Radio X4 terminal 6
  • voice recognition low reference circuit A11 Radio X4 terminal 16

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

  1. Test for less than 5 ohms between the terminals listed below:
  • A11 Radio X4 terminal 6 and the K73 Telematics Communication Interface Control Module X2 terminal 6
  • A11 Radio X4 terminal 16 and the K73 Telematics Communication Interface Control Module X2 terminal 12

If 5 ohms greater

Repair the open/high resistance in the circuit.

If less than 5 ohms

  1. Replace the A11 Radio. Connect all harness connectors.

NOTE: Refer to the Navigation System Owners Manual for voice recognition use and commands.

  1. Begin voice recognition for the radio and clearly speak one of the available commands.
  2. Verify the infotainment system responds correctly to the command.

If the infotainment system does not respond correctly to the command

  1. Clearly speak a different command.
  2. Verify the infotainment system responds correctly to the command.
  • If the infotainment system does not respond correctly to any commands, replace the K73 Telematics Communication Interface Control Module.

If the infotainment system responds correctly to the command

  1. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio or telematics communication interface control module replacement, programming, and setup.

Onstar audio malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

When an OnStar keypress is made, a serial data message is sent to the audio system to mute all radio functions and output OnStar originated audio. After the audio system is muted, the telematics communication interface control module transmits signals to the audio system on the audio signal and audio common circuits.

Reference Information

Schematic Reference

  • OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)
  • Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, radio ON.
  2. Verify that audio is heard clearly through all speaker channels when tuning radio to a known good station.

If audio is not heard clearly

Refer to Speaker Malfunction

If audio is heard clearly

  1. Verify that the Connecting to OnStar message is heard clearly through the audio system when the OnStar blue button is pressed.

If OnStar message is noisy or distorted

Refer to Circuit/System Testing

If OnStar message is heard clearly

  1. All OK.

Circuit/System Testing

  1. Ignition OFF and vehicle systems OFF, disconnect the X2 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 4 V between each of the signal circuits listed below and ground:
  • Terminal 1
  • Terminal 2

If 4 V or greater

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio, ignition ON.
  2. Test for less than 1 V between the signal circuits and ground.
  • If greater than 1 V, repair the short to voltage in the circuit.
  • If less then 1 V, replace the A11 Radio

If less than 4 V

  1. Ignition OFF.
  2. Test for infinite resistance between each of the signal circuits listed below and ground:
  • Terminal 1
  • Terminal 2

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

  1. Disconnect the X1 harness connector at the A11 Radio.
  2. Test for less than 2 ohms in each of the signal circuits listed below end to end:
  • K73 Telematics Communication Interface Control Module Terminal 1 X2
  • K73 Telematics Communication Interface Control Module Terminal 2 X2

If 2 ohms or greater

Repair the open/high resistance in the circuit.

If less than 2 ohms

  1. Replace the K73 Telematics Communication Interface Control Module.
  2. Verify that the Connecting to OnStar message is heard clearly through the audio system when the OnStar blue button is pressed.

If audio is not heard clearly

Replace the A11 Radio.

If audio is heard clearly

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair procedure.

Control Module References for radio or telematics communication interface control module replacement, programming, and setup.

No global positioning system (GPS) reception

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The navigation antenna is connected to the Telematics Communication Interface Control Module. The module supplies 5 V to the antenna to power the internal amplifier through the center conductor of the antenna coax cable.

When the vehicle is equipped with the optional navigation radio, a Navigation Antenna Signal Splitter is installed to distribute the navigation signal to both the Telematics Communication Interface Control Module and the navigation radio. The Telematics Communication Interface Control Module supplies 5 V through the coax cable to power the internal antenna amplifier through the signal splitter.

Diagnostic Aids

  • The scan tool Telematics Communication Interface Control Module GPS signal parameter will display a Yes or No dependent upon whether or not the module sees an increment of the seconds transmitted by GPS signals to the Telematics Communication Interface Control Module. Upon entering this screen, the GPS signal title will initially display Yes, regardless of the presence of time increment, for at least 2 seconds, while the algorithm in the scan tool determines the status of the clock. If increment is found, Yes is continually displayed. If the clock remains static, No is displayed. The scan tool looks for increment every second, regardless of current display.
  • Inaccurate or aged GPS position concerns which are no longer present may have been due to the temporary loss of GPS signal reception by the vehicle. Conditions such as tunnels or parking structures will restrict the cellular phone and navigation antenna from a clear view of the satellites in the sky and may have caused this temporary data loss.
  • The GPS requires a clear line of sight to the sky to operate properly. In most cases the GPS will not have reception near tall buildings or inside structures.

Reference Information

Schematic Reference

  • OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)
  • Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

  • OnStar Description and Operation
  • Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-49903 OnStar Antenna Diagnostic Tool Kit

Circuit/System Verification

NOTE: The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 minutes after turning the ignition ON for the vehicle to acquire the GPS satellites signal.

  1. Ignition ON.
  2. Verify that no DTCs are set.

If any DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

If no DTCs are set

  1. Verify that an OnStar advisor can locate the vehicle after performing a blue button press.
  • If the advisor can not locate the vehicle and the vehicle is not equipped with a navigation radio

Refer to Circuit System Testing Without Navigation Radio.

  • If the advisor can not locate the vehicle and the vehicle is equipped with a navigation radio
  • Refer to Circuit System Testing With Navigation Radio.
  • If the advisor can locate the vehicle
  1. Verify that the NO GPS symbol/message is not displayed on the radio.
  • If the NO GPS symbol/message is displayed

Refer to Circuit System Testing With Navigation Radio- Step 9.

  • If the NO GPS symbol/message is not displayed
  1. All OK.

Circuit/System Testing

without Navigation Radio

  1. Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module.
  2. Using the EL-49903 OnStar Antenna Diagnostic Tool Kit , connect the EL-49903-3 antenna to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON.
  3. Verify that an OnStar advisor can locate the vehicle after performing a blue button press.
  • If the advisor can not locate the vehicle

Replace the K73 Telematics Communication Interface Control Module.

  • If the advisor can locate the vehicle
  1. Test the coax cable between the K73 Telematics Communication Interface Control Module and the T4G Cellular Phone, Navigation, and Digital Radio Antenna. Refer to component testing.
  • If the coax cable does not pass the test

Replace the coax cable.

  • If the coax cable passes the test
  1. Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.

with Navigation Radio

NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Ignition OFF, disconnect the T4G Cellular Phone, Navigation, and Digital Radio Antenna coax cable at the T15 Navigation Antenna Signal Splitter.
  2. Using the EL-49903 OnStar Antenna Diagnostic Tool Kit , connect the EL-49903-3 antenna to the T15 Navigation Antenna Signal Splitter. Place the test antenna on the roof of the vehicle, ignition ON.
  3. Verify that an OnStar advisor can not locate the vehicle after performing a blue button press.

If the advisor can locate the vehicle

  1. Test the coax cable between the T15 Navigation Antenna Signal Splitter and the T4G Cellular Phone, Navigation, and Digital Radio Antenna. Refer to Component Testing.
  • If the coax cable does not pass the test

Replace the coax cable.

  • If the coax cable passes the test
  1. Replace the T4G cellular phone, navigation and digital radio antenna.

If the advisor can not locate the vehicle

  1. Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module.
  2. Using the EL-49903 OnStar Antenna Diagnostic Tool Kit , connect the EL-49903-3 antenna to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON.
  3. Verify that an OnStar advisor can locate the vehicle after performing a blue button press.
  • If the advisor can not locate the vehicle.

Replace the K73 Telematics Communication Interface Control Module.

  • If the advisor can locate the vehicle.
  1. Ignition OFF.
  2. Test the coax cable between the T15 Navigation Antenna Signal Splitter and the K73 Telematics Communication Interface Control Module. Refer to Component Testing.
  • If the coax cable does not pass the test.

Replace the coax cable.

  • If the coax cable passes the test.
  1. Ignition OFF, disconnect the GPS coax cable at the A11 Radio.
  2. Connect the EL-49903 OnStar Antenna Diagnostic Tool Kit to the A11 Radio and place the test antenna on the roof of the vehicle.
  3. Ignition ON.
  4. Verify that the NO GPS symbol/message is not displayed on the A11 Radio.
  • If the NO GPS symbol/message is displayed

Replace the A11 Radio

  • If the NO GPS symbol/message is not displayed.
  1. Ignition OFF.
  2. Test the coax cable between the T15 Navigation Antenna Signal Splitter and the A11 Radio. Refer to Component Testing.
  • If the coax cable does not pass the test.

Replace the coax cable.

  • If the coax cable passes the test.
  1. Test or replace the T15 Navigation Antenna Signal Splitter.

Component Testing

CAUTION: Refer to Test Probe Caution .

NOTE:

  • Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.
  • To prevent false reading when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.
  • The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between the coax cable center terminal end to end.
  • If 5 ohms or greater

Replace the coax cable.

  • If less than 5 ohms
  1. Test for greater than 5 ohms between the coax cable outer shield end to end.
  • If 5 ohms or greater

Replace the coax cable.

  • If less than 5 ohms
  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.
  • If less than infinite resistance

Replace the coax cable.

  • If infinite resistance
  1. 5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Radio Antenna Base Replacement
  • Control Module References for radio or telematics communication interface control module replacement, programming, and setup.

Onstar button led malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B2476 04

Cellular Phone Select Service Switch Open

DTC B2476 59

Cellular Phone Select Service Switch Protection Time-out

Cellular Phone Select Service Switch Protection Time-out

Cellular Phone Select Service Switch Range/Performance

Diagnostic Fault Information

Diagnostic Fault Information

Circuit Description

The OnStar status LEDs are located in the inside rearview mirror telematic button assembly. The green LED is illuminated when the system is ON and operating normally. When the green LED is green and flashing, it is an indication that a call is in progress. When the red LED is illuminated, a system malfunction is present. In the event there is a system malfunction and the OnStar system is still able to make a call, the LED will flash red during the call. The OnStar LEDs are controlled by the telematics communication interface control module via the keypad green LED control circuit and the keypad red LED control circuit.

Conditions for Running the DTC

  • Ignition ON.
  • Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

B2476 04

The telematics communication interface control module detects a short to voltage or an open/high resistance on the keypad 10 V reference circuit.

B2482 and B2476 59

The telematics communication interface control module detects a valid signal on the keypad signal circuit for longer than 15 s. If one of the OnStar buttons is held or stuck for 15 s or greater, the telematics communication interface control module will set this DTC.

Action Taken When the DTC Sets

  • The OnStar status LED turns red.
  • No calls can be placed.
  • The telematics communication interface control module will ignore all inputs from the OnStar button assembly.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: If the green LED is off with the ignition ON and the LED does not function when commanded with the scan tool, contact the OnStar Center to confirm the vehicle has a current subscription.

  1. Ignition ON.
  2. Verify no DTC are set.
  • If any DTC are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle

  • If no DTC are set
  1. Verify that the green LED turns ON and OFF when commanding the Green Indicator ON and OFF with a scan tool.
  • If the green LED does not turn ON and OFF

Refer to Circuit/System Testing - Green LED Test

  • If the green LED turns ON and OFF
  1. Verify that the red LED turns ON and OFF when commanding the Red Indicator ON and OFF with a scan tool.
  • If the red LED does not turn ON and OFF

Refer to Circuit/System Testing - Red LED Test

  • If the red LED turns ON and OFF
  1. All OK.

Circuit/System Testing

Green LED Test

  1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the A10 Inside Rearview Mirror. It may take up to 2 min for all vehicle systems to power down. Doors closed, courtesy lamps OFF.
  2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

  1. Ignition ON.
  2. Test for less than 1 V between the control circuit terminal 6 and ground while commanding the Green Indicator OFF with a scan tool.

If 1 V or greater

  1. Ignition OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the control circuit terminal 6 and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.

If less than 1 V

  1. Test for greater than 8 V between the control circuit terminal 6 and ground while commanding the Green Indicator ON with a scan tool.

If 8 V or less

  1. Ignition OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the control circuit terminal 6 and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the control circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the K73 Telematics Communication Interface Control Module.

If greater than 8 V

  1. Test or replace the A10 Inside Rearview Mirror.

Red LED Test

  1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the A10 Inside Rearview Mirror. It may take up to 2 min for all vehicle systems to power down. Doors closed, courtesy lamps OFF.
  2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

  1. Ignition ON.
  2. Test for less than 1 V between the control circuit terminal 7 and ground while commanding the Red Indicator OFF with a scan tool.

If 1 V or greater

  1. Ignition OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the control circuit terminal 7 and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.

If less than 1 V

  1. Test for greater than 8 V between the control circuit terminal 7 and ground while commanding the Red Indicator ON with a scan tool.

If 8 V or less

  1. Ignition OFF, disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the control circuit terminal 7 and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the control circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the K73 Telematics Communication Interface Control Module.

If greater than 8 V

  1. Test or replace the A10 Inside Rearview Mirror.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Inside Rearview Mirror Replacement
  • Control Module References for telematics communication interface control module replacement, programming and setup.

Onstar call center remote function requests malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The telematics communication interface control module has the capability of commanding the horn, initiating door lock/unlock, or operating the exterior lamps using the serial data circuits. These functions are commanded by the OnStar Call Center per a customer request.

Diagnostic Aids

The customer concern may have been due to a lack of cellular service in a given area, or a failure in the National Cellular Network infrastructure that has since been corrected.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE:

  • It is necessary to inform the OnStar Call Center advisor that this call is for vehicle diagnostic purposes.
  • It is necessary to have the vehicle in an open outside area where a cellular call can be successfully placed and GPS data can be received from satellites.
  1. Ignition ON.
  2. Verify that the horn, lights, and the door locks on the vehicle operate properly.

If an applicable vehicle system does not operate properly

Refer to Diagnostic System Check - Vehicle .

  • If all applicable vehicle systems operate properly
  1. Verify that a call can be successfully placed to the OnStar Call Center by pressing the blue OnStar button.
  • If unable to contact the OnStar call center

Refer to Unable to Contact OnStar Call Center

  • If able to contact the OnStar Call Center
  1. Verify with the OnStar advisor that all remote functions (door locks, lights, and horn) work.
  • If the remote functions do not operate when requested

Replace the K73 Telematics Communication Interface Control Module

  • If the remote functions operate when requested
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for telematics communication interface control module replacement, programming and setup.

Onstar button malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B2476 04

Cellular Phone Select Service Switch Open

DTC B2476 59

Cellular Phone Select Service Switch Protection Time-out

DTC B2482 00

Cellular Phone Select Service Switch Range/Performance

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The OnStar button assembly consists of 3 buttons: Call/Answer, OnStar Call Center, and OnStar Emergency. The telematics communication interface control module supplies the OnStar button assembly with 10 V via the 10 V reference circuit . Each of the buttons, when pressed, completes the circuit across a resistor allowing a specific voltage to be returned to the telematics communication interface control module over the keypad signal circuit. Depending upon the voltage range returned, the telematics communication interface control module is able to identify which button has been activated.

Conditions for Running the DTC

  • Ignition ON.
  • Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

B2476 04

The telematics communication interface control module detects a short to voltage or an open/high resistance on the keypad 10 V reference circuit.

B2482 and B2476 59

The telematics communication interface control module detects a valid signal on the keypad signal circuit for longer than 15 s. If one of the OnStar buttons is held or stuck for 15 s or greater, the telematics communication interface control module will set this DTC.

Action Taken When the DTC Sets

  • The OnStar status LED turns red.
  • No calls can be placed.
  • The telematics communication interface control module will ignore all inputs from the OnStar button assembly.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: Contact the OnStar Call Center first before pressing the emergency button in order to notify them of the test.

  1. Ignition ON.
  2. Verify no DTCs are set.
  • If any DTCs are set

Diagnostic Trouble Code (DTC) List - Vehicle

  • If no DTCs are set
  1. Verify that each button of the S51 Telematics Button Assembly operates normally by pressing each button individually.
  • If none of the buttons operate normally

Refer to Circuit/System Testing

  • If some, but not all, of the buttons operate normally

Test or replace the A10 Inside Rearview Mirror.

If all of the buttons operate normally

  1. All OK.

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A10 Inside Rearview Mirror. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

  1. Ignition ON.
  2. Test for 8.0-10.5 V between the 10 V reference circuit terminal 4 and ground.

If less than 8.0 V

  1. Ignition OFF, disconnect the harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the 10 V reference circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the 10 V reference circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the K73 Telematics Communication Interface Control Module

If greater than 10.5 V

  1. Ignition OFF, disconnect the harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the 10 V reference circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K73 Telematics Communication Interface Control Module.

If between 8.0-10.5 V

  1. Ignition OFF.
  2. Test for 500-900 ohms between the signal circuit terminal 3 and ground.

If less than 500 ohms

  1. Disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the K73 Telematics Communication Interface Control Module.

If greater than 900 ohms

  1. Disconnect the X1 harness connector at the K73 Telematics Communication Interface Control Module, ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V
  1. Ignition OFF.
  2. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the K73 Telematics Communication Interface Control Module.

If between 500-900 ohms

  1. Test or replace the A10 Inside Rearview Mirror.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Inside Rearview Mirror Replacement
  • Control Module References for telematics communication interface control module replacement, programming and setup.

ONSTAR STEERING WHEEL CONTROL FUNCTIONS MALFUNCTION

Some vehicles equipped with the OnStar system have the capability of accessing voice mailboxes and other automated phone systems by means of the steering wheel controls, while the OnStar Personal Calling feature is in use. If the "Talk" or "Mute" button (depending upon the vehicle) on the steering wheel controls is depressed during an OnStar Personal Calling call, the telematics communication interface control module receives the message on the serial data bus from either the radio or body control module. This message is interpreted as a request to turn any spoken numbers into dual tone multi-frequency tones to be delivered over the airwaves to the phone system the user is communicating with. Complete instructions for operation of these features can be found in the information provided to the customer with the OnStar system.

The steering wheel controls are a resistor network that consist of multiple momentary contact switches and a series of resistors. The switches and resistor network are arranged so that each switch has a different resistance value. When a switch is pressed, a voltage drop occurs in the resistor network, which produces a specific voltage value unique to the switch selected, to be interpreted by either the radio or BCM. In the event the OnStar steering wheel control functions are inoperative, technicians should refer to Steering Wheel Controls Malfunction , to begin diagnosis of the steering wheel control concern.

Radio controls malfunction (monochrome display)

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The radio controls are supplied battery voltage and ground . The radio controls operate radio functions through serial data messages. The radio controls communicate control requests to the info display module through LIN serial data. The info display module communicates these control requests to the radio through serial data.

Diagnostic Aids

If the info display module is inoperative, the main radio controls will also be inoperative. The radio may be able to be operated with the steering wheel controls, if equipped.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Display RPO UFD

  1. Ignition ON, radio ON,
  2. Verify the info display turns on and information is shown on the display.
  • If the info display module does not turn on, or information is not shown in the display.

Refer to Radio Information Display Malfunction (Monochrome Display), Radio Information Display Malfunction (Color Display)

  • If the info display turns on and information is shown on the display.
  1. Verify that all radio controls operate and perform the correct function.
  • If some, or all, of the radio controls do not operate normally.

Replace the A22 Radio Controls.

  • If all radio controls operate and perform the correct function.
  1. All OK.

Display RPO UAG

  1. Ignition ON, A11 Radio ON.
  2. Verify that all radio controls operate and perform the correct function.

If some, but not all, controls operate normally.

Replace the A22 Radio Controls.

If all controls are inoperative.

Refer to Circuit/System Testing

If all radio controls operate and perform the correct function.

  1. All OK.

Circuit/System Testing

Display RPO UAG

  1. Ignition OFF, disconnect the harness connector at the A22 Radio Controls.
  2. Test for less than 10 ohms between the ground circuit terminal 3 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

  1. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
  • If the test lamp does not illuminate and the circuit fuse is good.
  1. Ignition OFF.
  2. Test for less than 2 ohms in the B+ circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, refer to Power Mode Mismatch .

If the test lamp does not illuminate and the circuit fuse is open.

  1. Ignition OFF.
  2. Test for infinite resistance between the B+ circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the A22 Radio Controls.

If the test lamp illuminates.

  1. Ignition ON.
  2. Test for 2-11.5 V between the serial data circuit terminal 6 and ground.

If less than 2 V

  1. Ignition OFF, disconnect the X1 harness connector at the P17 Info Display Module.
  2. Test for infinite resistance between the serial data circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the serial data circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the P17 Info Display Module.

If greater than 11.5 V

  1. Ignition OFF, disconnect the X1 harness connector at the P17 Info Display Module. Ignition ON.
  2. Test for less than 1 V between the serial data circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the P17 Info Display Module.

If between 2-11.5 V

  1. Test or replace the A22 Radio Controls.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  • Driver Information Display Replacement (UAG) , Driver Information Display Replacement (UDN)
  • Control Module References for radio control assembly replacement, programming, and setup.

Radio controls malfunction (color display)

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The radio controls are supplied battery voltage and ground. The radio controls the power state of the controls via a wake up circuit. Communications between the radio controls and the radio are through the serial data circuits.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, A11 Radio ON.
  2. Verify that all radio controls operate and perform the correct function.

If some, but not all, controls operate normally.

Replace the A20 Radio/HVAC Controls.

If all controls are inoperative.

Refer to Circuit/System Testing

If all radio controls operate and perform the correct function.

  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the A20 Radio/HVAC Controls.
  2. Test for less than 10 ohms between the ground circuit terminal 3 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

  1. Test for less than 20 ohms between the shield ground circuit terminal 7 and ground.

If 20 ohms or greater

  1. Ignition OFF, disconnect the X1 connector at the A11 Radio.
  2. Test for less than 2 ohms in the data shield circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If less than 20 ohms

  1. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
  • If the test lamp does not illuminate and the circuit fuse is good
  1. Ignition OFF.
  2. Test for less than 2 ohms in the B+ circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, refer to Power Mode Mismatch

If the test lamp does not illuminate and the circuit fuse is open

  1. Ignition OFF.
  2. Test for infinite resistance between the B+ circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the A20 Radio Controls.

If the test lamp illuminates.

  1. Ignition ON.
  2. Test for 2-3 V between the serial data circuit terminals listed below and ground.
  • Terminal 4
  • Terminal 8

If less than 2 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the serial data circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the serial data circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 3 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the serial data circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If between 2-3 V

  1. Test for less than 1 V between the control circuit terminals listed below and ground.
  • Terminal 1
  • Terminal 5
  • If greater than 1 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the control circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If less than 1 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the control circuit terminals listed below and ground.
  • A20 Radio/HVAC Controls terminal 1
  • A20 Radio/HVAC Controls terminal 5
  • If less than infinite resistance,

Repair the short to ground on the circuit.

  • If infinite resistance
  1. Test for less than 2 ohms between the control circuits listed below.
  • A20 Radio/HVAC Controls terminal 1 and the A11 Radio terminal 13 X1
  • A20 Radio/HVAC Controls terminal 5 and the A11 Radio terminal 27 X1
  • If 2 ohms or greater

Repair the open/high resistance in the circuit.

If less than 2 ohms.

  1. Replace the A20 Radio/HVAC Controls. Connect all harness connectors.
  2. Ignition ON, radio ON.
  3. Verify that all radio controls operate and perform the correct function.

If the radio controls still malfunction.

Replace the A11 Radio.

If all radio controls operate and perform the correct function.

  1. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for radio or radio control assembly replacement, programming, and setup.

Radio information display malfunction (monochrome display)

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The radio controls and information display are separate components from the radio. Each component is supplied battery voltage and ground. The radio uses the wake up circuit to control the power state of the display. The radio controls communicate with the info display module through the LIN serial data circuit. Display backlighting dimming level, graphical data, and radio control inputs are communicated over the data circuits between the display and the radio.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the P17 Info Display Module.
  2. Test for less than 10 ohms between the ground circuit terminal 2 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

less than 10 ohms.

  1. Test for less than 20 ohms between the data shield circuit terminal 6 and ground.

If 20 ohms or greater.

  1. Ignition OFF, disconnect the X1 connector at the A11 Radio.
  2. Test for less than 2 ohms in the data shield circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If less than 20 ohms.

  1. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.
  • If the test lamp does not illuminate and the circuit fuse is good.
  1. Ignition OFF.
  2. Test for less than 2 ohms in the B+ circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, refer to Power Mode Mismatch .

If the test lamp does not illuminate and the circuit fuse is open.

  1. Ignition OFF.
  2. Test for infinite resistance between the B+ circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the P17 Info Display Module.

If the test lamp illuminates

  1. Ignition ON.
  2. Test for 2-3 V between the data circuit terminals listed below and ground.
  • terminal 7
  • terminal 8
  • If less than 2 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the data circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the data circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.
  • If greater than 3 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.
  • If 2-3 V
  1. Test for less than 1 V between the control circuit terminals listed below and ground.
  • terminal 4
  • terminal 5
  • If greater than 1 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the control circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio
  • If less than 1 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the control circuit terminals listed below and ground.
  • P17 Info Display Module terminal 4
  • P17 Info Display Module terminal 5
  • If less than infinite resistance,

Repair the short to ground on the circuit.

If infinite resistance

  1. Test for less than 2 ohms between the control circuits listed below.
  • P17 Info Display Module terminal 4 and the A11 Radio terminal 13 X1
  • P17 Info Display Module terminal 5 and the A11 Radio terminal 27 X1
  • If 2 ohms or greater

Repair the open/high resistance in the circuit.

If less than 2 ohms.

  1. Replace the P17 Information Display Module. Connect all harness connectors.
  2. Ignition ON, radio ON.
  3. Verify the P17 Info Display Module turns on and information is shown on the display.

If the information display still malfunctions.

Replace the A11 Radio.

  • If the info display module turns on and information is shown on the display.
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Driver Information Display Replacement (UAG) , Driver Information Display Replacement (UDN)
  • Control Module References for radio replacement, programming, and setup.

Radio information display malfunction (color display)

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The info display module has continuous power and ground. When the radio is on, a discrete 12 V signal is supplied on the radio controls wakeup circuit to the info display module. This signal is used to control the power state of the module, which is active when the signal is high and inactive when the signal is low.

The info display module receives digital video data from the radio for on-screen display information through the video signal circuits. Backlighting dimming level is controlled by the radio through a pulse width modulated circuit. The output is determined by dimming level information the radio receives via serial data.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Verify DTC B1265 is not set.
  • If DTC B1265 is set.

Refer to Diagnostic Trouble Code (DTC) List - Vehicle .

  • If DTC B1265 is not set.
  1. Ignition ON, radio ON.
  2. Verify the P17 Info Display Module turns on and information is shown on the display.
  • If the P17 Info Display Module does not turn on, or information is not shown in the display.

Refer to Circuit/System Testing

  • If the P17 Info Display Module turns on and information is shown on the display.
  1. All OK.

Circuit/System Testing

  1. Ignition OFF.
  2. Verify the video interface cable is properly connected at the P17 Info Display Module X2 and A11 Radio X5 connections and there is no damage to the cable or connections.

If connection problems or cable damage is noted.

Perform the appropriate repair or replacement to correct any issues.

If no issues are found with the video interface cable.

  1. Disconnect the X1 harness connector at the P17 Info Display Module.
  2. Test for less than 10 ohms between the ground circuit terminal 2 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.
  • If less than 10 ohms
  1. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.

If the test lamp does not illuminate and the circuit fuse is good

  1. Ignition OFF.
  2. Test for less than 2 ohms in the B+ circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, refer to Power Mode Mismatch

If the test lamp does not illuminate and the circuit fuse is open

  1. Ignition OFF.
  2. Test for infinite resistance between the B+ circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the P17 Info Display Module.
  • If the test lamp illuminates.
  1. Ignition ON, radio ON.
  2. Verify that a test lamp illuminates between the control circuit terminal 6 and ground.
  • If the test lamp does not illuminate.
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the control circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the control circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.
  • If the test lamp illuminates.
  1. Ignition ON, lights ON, set the I/P dimming switch to full bright.
  2. Test for 5-7 V between the dimming control circuit terminal 3 and ground.

If less than 5 V

  1. Ignition OFF, disconnect the X4 harness connector at the A11 Radio.
  2. Test for infinite resistance between the control circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the control circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 7 V

  1. Ignition OFF, disconnect the X4 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the control circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.
  • If between 5-7 V
  1. Verify the voltage increases steadily to 6-7 V at full dim while using the I/P dimming switch to decrease the dimming level.

If less than 6 V

  1. Ignition OFF, disconnect the X4 harness connector at the A11 Radio.
  2. Test for infinite resistance between the control circuit and ground
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the control circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 7 V

  1. Ignition OFF, disconnect the X4 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the control circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If between 6-7 V

  1. Replace the video interface cable.
  2. Connect all harness connectors.
  3. Ignition ON, radio ON.
  4. Verify the P17 Info Display Module turns on and information is shown on the display.

If the P17 Info Display Module does not turn on, or information is not shown in the display.

  1. Replace the P17 Information Display Module.
  2. Ignition ON, radio ON.
  3. Verify the P17 Info Display Module turns on and information is shown on the display.
  • If the information display malfunctions, replace the A11 Radio.
  • If the info display module turns on and information is shown on the display.
  1. All OK.

If the info display module turns on and information is shown on the display.

  1. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Driver Information Display Replacement (UAG) , Driver Information Display Replacement (UDN)
  • Control Module References for radio replacement, programming, and setup.

Radio poor reception

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B125A 02

Antenna Signal Circuit Short to Ground

DTC B125A 04

Antenna Signal Circuit Open Circuit

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The multi-band antenna is located on the roof of the vehicle. The radio antenna is enabled when the radio is turned on. The radio provides battery voltage to the antenna using the center conductor of the antenna coaxial cable. When a 12 V signal is seen on the center conductor of the antenna coax, both AM and FM signals are amplified.

Conditions for Running the DTC

  • Ignition ON.
  • Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

B125A 02

The radio detects a short to ground in the antenna signal circuit center conductor.

B125A 04

The radio detects an open in the antenna signal circuit center conductor.

Action Taken When the DTC Sets

Radio reception may be poor or not available.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clears after 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS -INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, A11 Radio ON.
  2. Verify station reception is normal when tuned to several known good AM and FM stations.
  • If AM or FM reception is poor.

Refer to Circuit/System Testing

If reception is normal

  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the radio antenna coax cable from the A11 Radio and from the T4M Radio Antenna.
  2. Verify the antenna coax cable passes the coax cable component test. Refer to Component Testing.
  • If the coax cable does not pass the test

Replace the antenna coax cable

  • If the coax cable passes the test
  1. Connect the radio antenna coax cable to the A11 Radio.
  2. Ignition ON, A11 Radio ON.
  3. Verify a test lamp illuminates between the antenna coax cable center terminal at the T4M Radio Antenna and chassis ground.

If the test lamp does not illuminate

Replace the A11 Radio.

If the test lamp illuminates

  1. Test or replace the T4M Radio Antenna.

Component Testing

CAUTION: Refer to Test Probe Caution .

NOTE:

Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.

To prevent false reading when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between coax cable center terminal end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for less than 5 ohms between the coax cable outer shield end to end.

If 5 ohms or greater

Replace the coax cable

If less than 5 ohms

  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.

If less than infinite resistance

Replace the coax cable

If infinite resistance

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Radio Antenna Base Replacement
  • Control Module References for radio replacement, programming, and setup.

SPEAKER REPLACEMENT REFERENCE

Speaker Replacement Reference

Speaker Replacement Reference

Speaker malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and audio amplifier have a DC bias voltage that is approximately one half of battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5 V DC. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. The frequency (Hz) of the AC voltage signal is directly related to the frequency of the input (audio source playing) to the audio system. Both the DC bias voltage and the AC voltage signals are needed for the audio system to properly produce sound.

Diagnostic Aids

  • Improper speaker mounting or loose trim may cause an audible buzz or distortion. Inspect the appropriate speaker and the surrounding interior trim for proper and secure mounting.

    The EL-50334-6 Audio System Diagnostic CD contains audio tracks that can be used to duplicate and isolate such concerns. Tracks 11 and 12 contain audio sweep tones for testing for speaker and grill rattles.

    If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.

  • The test tones on the CD may be copied to a USB drive or other device to use during testing.
  • When equipped with an amplifier, it is possible for some individual circuit faults to affect more than one speakers operation. Perform diagnostic tests in the sequence listed to avoid misdiagnosis.
  • The amplifier control circuit will measure less than 1 V when the mute function is OFF, and approximately 8 V DC when at full mute. When mute is active, the radio stops sending the varying AC voltage to the amplifier/speakers.

Reference Information

Schematic Reference

Radio/Navigation System Schematics (Encore), Radio/Navigation System Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Radio/Audio System Description and Operation (with Monochrome Display), Radio/Audio System Description and Operation (with Color Display)

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-50334-50 USB Cable and Adapter Kit

For equivalent regional tools, refer to Special Tools, Special Tools (MIT tool instructions).

Circuit/System Verification

Without Amplifier

  1. Ignition ON, A11 radio ON, mute OFF.
  2. Verify clear audio is heard from each speaker, adjusting fade and balance controls to test each speaker individually.
  • If audio is inoperative from one or more speakers, or the audio emitted is not clear

Refer to Circuit/System Testing - Speaker Malfunction - without Amplifier

  • If clear audio is heard from all speakers
  1. All OK.

With Amplifier

  1. Ignition ON, A11 radio ON, mute OFF.
  2. Verify clear audio is heard from each speaker, adjusting fade and balance controls to test each speaker individually.

If audio is inoperative from one or more speakers, or the audio emitted is not clear

Refer to Circuit/System Testing - Speaker Malfunction - with Amplifier

If clear audio is heard from all speakers

  1. All OK.

Circuit/System Testing

Speaker Malfunction - without Amplifier

  1. Ignition OFF, disconnect the harness connector at the appropriate P19 Speaker. Ignition ON, radio ON, mute OFF.
  2. Test for 5-7 V between each audio signal circuit terminal 1 and terminal 2 and ground.

If less than 5 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 7 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.

If between 5-7 V

NOTE: In the following tests, audio signal frequencies (Hz) will be tested. To prevent misdiagnosis, the door chime must be OFF during testing. Ensure the driver door latch is closed during testing.

  1. .Play track number three (50 Hz bass test tone) from the EL-50334-6 Audio Test CD.
  2. Test for 49-51 Hz AC between each signal circuit terminal 1 and terminal 2 and ground.

If not between 49-51 Hz AC

Replace the A11 Radio.

If between 49-51 Hz AC

  1. Test or replace the P19 Speaker.

Speaker Malfunction - with Amplifier

NOTE: In the following tests, audio signal frequencies (Hz) will be tested. To prevent misdiagnosis, the door chime must be OFF during testing. Ensure the driver door latch is closed during testing.

  1. Ignition OFF, disconnect the X1 harness connector at the T3 Audio Amplifier.
  2. Test for less than 10 ohms between the ground circuit terminal 8 and ground.

If 10 ohms or greater

  1. Ignition OFF.
  2. Test for less than 2 ohms in the ground circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

  1. Verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.

If the test lamp does not illuminate and the circuit fuse is good

  1. Ignition OFF.
  2. Test for less than 2 ohms in the B+ circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, refer to Power Mode Mismatch

If the test lamp does not illuminate and the circuit fuse is open

  1. Ignition OFF.
  2. Test for infinite resistance between the B+ circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the T3 Audio Amplifier.

If the test lamp illuminates

  1. Disconnect the X3 harness connector at the T3 Audio Amplifier.
  2. Verify a test lamp does not illuminate between the control circuit terminal 8 and ground.

If the test lamp illuminates

  1. Disconnect the X1 harness at the A11 Radio.
  2. Verify a test lamp does not illuminate between the control circuit and ground.
  • If the test lamp illuminates, repair the short to voltage on the circuit.
  • If the test lamp does not illuminate, replace the A11 Radio.
  • If the test lamp does not illuminate
  1. Ignition ON, A11 Radio ON.
  2. Verify a test lamp illuminates between the control circuit terminal 8 and ground.

If the test lamp does not illuminate

  1. Ignition OFF. Disconnect the X1 harness at the A11 Radio.
  2. Test for less than 2 ohms in the control circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.
  • If the test lamp illuminates
  1. Radio ON, mute ON.
  2. Test for 7.5-8.5 V between the control circuit terminal 11 and ground.
  • If greater than 8.5 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the control circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.
  • If less than 7.5 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the control circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.
  • If between 7.5-8.5 V
  1. Radio ON, mute OFF.
  2. Test for less than 1 V between the control circuit terminal 11 and ground.
  • If greater than 1 V

Replace the A11 Radio.

  • If less than 1 V
  1. Test for 5-7 V between the signal circuit terminals listed below and ground:
  • Left front low level audio signal (+) terminal 15
  • Left front low level audio signal (-) terminal 7
  • Right front low level audio signal (+) terminal 14
  • Right front low level audio signal (-) terminal 6
  • Left rear low level audio signal (+) terminal 13
  • Left rear low level audio signal (-) terminal 5
  • Right rear low level audio signal (+) terminal 12
  • Right rear low level audio signal (-) terminal 4
  • If less than 5 V
  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the A11 Radio.

If greater than 7 V

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio. Ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the A11 Radio.
  • If between 5-7 V
  1. Insert the EL-50334-6 Audio Test CD from the EL-50334-50 USB cable and adapter kit. Play track number three (50 Hz bass test tone) from the test CD.
  2. Test for 49-51 Hz AC between the audio signal circuit terminals listed below and ground:
  • Left front low level audio signal (+) terminal 15
  • Left front low level audio signal (-) terminal 7
  • Right front low level audio signal (+) terminal 14
  • Right front low level audio signal (-) terminal 6
  • Left rear low level audio signal (+) terminal 13
  • Left rear low level audio signal (-) terminal 5
  • Right rear low level audio signal (+) terminal 12
  • Right rear low level audio signal (-) terminal 4
  • If not between 49-51 Hz AC

Replace the A11 radio.

  • If between 49-51 Hz AC
  1. Ignition OFF, connect all harness connectors.
  2. Disconnect the harness connector at the appropriate P19 Speaker. Ignition ON, A11 Radio ON.
  3. Test for 5-7 V between the appropriate speaker signal terminals listed below and ground:
  • Speaker signal (-) circuit terminal 1
  • Speaker signal (+) circuit terminal 2
  • If less than 5 V
  1. Ignition OFF, disconnect the X2 harness connectors at the T3 Audio Amplifier.
  2. Test for infinite resistance between the signal circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance
  1. Test for less than 2 ohms in the signal circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the T3 Audio Amplifier

If greater than 7 V

  1. Ignition OFF, disconnect the X2 harness connectors at the T3 Audio Amplifier. Ignition ON.
  2. Test for less than 1 V between the signal circuit and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the T3 Audio Amplifier.
  • If between 5-7 V
  1. Mute OFF, play track number three (50 Hz bass test tone) from the test CD.
  2. Test for 49-51 Hz AC between each signal circuit terminal and ground.
  • If not between 49-51 Hz AC

Replace the T3 Audio Amplifier.

  • If between 49-51 Hz AC
  1. Test or replace the P19 Speaker.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Speaker Replacement Reference
  • Control Module References for amplifier or radio replacement, programming, and setup

Unable to contact onstar call center

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The telematics communication interface control module is a cellular device that allows the user to communicate data and voice signals over the national cellular network. When an OnStar keypress is made, the telematics communication interface control module activates and connects the system to the cellular carriers communication system by interacting with the national cellular infrastructure. The module sends and receives all cellular communications over the cellular phone and navigation antenna and cellular antenna coax.

Diagnostic Aids

  • The customer concern may have been due to a lack of cellular service in a given area. A failure in the National Cellular Network infrastructure at the time of the customers failed connection that has since been repaired may also have been the cause.
  • If an OnStar emergency call is able to successfully connect the vehicle to the OnStar Call Center when an OnStar Call Center button press is not, there may be a failure in the ability of the OnStar system in the vehicle to be recognized by the local cellular carrier.
  • If the prompt "OnStar request ended" is heard, without pressing the white dot button at the end of the OnStar keypress, the OnStar system at one time has made a successful cellular connection, but was unable to complete the call.
  • It is important to have the vehicle in an open outside area where a cellular call can be successfully placed and GPS data can be received from satellites.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-49903 GM OnStar Antenna Diagnostic Tool Kit

Circuit/System Verification

NOTE: The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 minutes after turning the ignition ON for the GPS satellites to acquire vehicle signal.

  1. Ignition ON.
  2. Verify that DTC B2470 is not set.
  • If DTC B2470 is set

Refer to DTC B2470

  • If DTC B2470 is not set
  1. Verify that a call can be successfully placed to the OnStar Call Center by pressing the blue OnStar button.
  • If unable to connect with the OnStar Call Center.

Refer to bulletin PIC4310.

If able to connect with the OnStar Call Center

  1. All OK.

Circuit/System Testing

NOTE:

  • The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.
  • The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 minutes after turning the ignition ON for the GPS satellites to acquire vehicle signal.

Without Navigation Radio

  1. Ignition OFF and all vehicle systems OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 minutes for all vehicle systems to power down.
  2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 GM OnStar antenna diagnostic tool kit to the K73 Telematics Communication Interface Control Module.

    Place the test antenna on the roof of the vehicle, ignition ON.

  3. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
  • If the DTC sets

Replace the K73 Telematics Communications Interface Control Module.

  • If the DTC does not set
  1. Ignition OFF.
  2. Disconnect the EL-49903 GM OnStar antenna diagnostic tool kit from the K73 Telematics Communication Interface Control Module
  3. Test the coax cable. Refer to Component Testing.
  • If the coax cable does not pass the test

Replace the coax cable.

  • If the DTC does not set
  1. Ignition OFF.
  2. Disconnect the EL-49903 GM OnStar antenna diagnostic tool kit from the K73 Telematics Communication Interface Control Module
  3. Test the coax cable. Refer to Component Testing.
  • If the coax cable does not pass the test

Replace the coax cable.

  • If the coax cable passes the test
  1. Test or replace the T4E Cellular Phone and Navigation Antenna.

With Navigation Radio

  1. Ignition OFF and all vehicle systems OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 minutes for all vehicle systems to power down.
  2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 GM OnStar antenna diagnostic tool kit to the K73 Telematics Communication Interface Control Module.

    Place the test antenna on the roof of the vehicle, ignition ON.

  3. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
  • If the DTC sets

Replace the K73 Telematics Communication Interface Control Module.

  • If the DTC does not set
  1. Ignition OFF, connect the coax cable to the K73 Telematics Communications Interface Control Module and disconnect the coax cable from the T15 Navigation Antenna Signal Splitter, ignition ON.
  2. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.

If less than 4.5 V

  1. Test the coax cable between the K73 Telematics Communications Interface Control Module and the T15 Navigation Antenna Signal Splitter. Refer to Component Testing.
  • If the coax does not successfully pass the component test, replace the coax.
  • If the coax successfully passes the coax test, replace the K73 Telematics Communications Interface Control Module.
  • If greater than 5.5 V
  1. Test the coax cable between the K73 Telematics Communications Interface Control Module and the T15 Navigation Antenna Signal Splitter. Refer to Component Testing.
  • If the coax cable does not pass the test, replace the coax.
  • If the coax cable passes the test, replace the K73 Telematics Communications Interface Control Module.
  • If between 4.5-5.5 V
  1. Ignition OFF, connect the coax cable to the T15 Navigation Antenna Signal Splitter and disconnect the coax cable from the T4E Cellular Phone and Navigation Antenna, ignition ON.
  2. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.

If less than 4.5 V

  1. Test the coax cable between the T15 Navigation Antenna Signal Splitter and the T4E Cellular Phone and Navigation Antenna. Refer to Component Testing.
  • If the coax does not successfully pass the component test, replace the coax.
  • If the coax successfully passes the coax test, test or replace the T15 Navigation Antenna Signal Splitter
  • If greater than 5.5 V
  1. Phone and Navigation Antenna. Refer to Component Testing.
  • If the coax cable does not pass the test, replace the coax.
  • If the coax cable passes the test, test or replace the T15 Navigation Antenna Signal Splitter
  • If between 4.5-5.5 V
  1. Test or replace the T4E Cellular Phone and Navigation Antenna.

Component Testing

CAUTION: Refer to Test Probe Caution

NOTE:

  • Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.
  • To prevent false readings when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.

Coax Cable Test

  1. Ignition OFF, disconnect the coax cable at both components.
  2. Test for less than 5 ohms between the coax cable center terminal end to end.
  • If 5 ohms or greater

Replace the coax cable.

  • If less than 5 ohms
  1. Test for greater than 5 ohms between the coax cable outer shield end to end.
  • If 5 ohms or greater

Replace the coax cable.

  • If less than 5 ohms
  1. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.
  • If less than infinite resistance

Replace the coax cable.

  • If infinite resistance
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Navigation Signal Splitter Replacement (Encore)
  • Radio Antenna Base Replacement
  • Control Module References for telematics communication interface control module replacement, programming and setup.

Onstar voice recognition malfunction

Diagnostic Instructions

  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The telematics communication interface control module is capable of interpreting voice commands received over the cellular microphone circuit. Speech recognition allows the user to speak to one computer in the vehicle, and one reached over the cellular communication network. The module attempts to understand the users command, and responds by speaking back, or by taking the appropriate action, e.g. dialing the phone.

Reference Information

Schematic Reference

OnStar/Telematics Schematics (Encore), OnStar/Telematics Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

OnStar Description and Operation

Electrical Information Reference

  • Circuit Testing
  • Connector Repairs
  • Testing for Intermittent Conditions and Poor Connections
  • Wiring Repairs

Circuit/System Verification

NOTE:

  • It is necessary to have the vehicle in an open outside area where a cellular call can be successfully placed and GPS data can be received from satellites.
  • The vehicle should be located in a quiet area.
  1. Ignition ON, press the blue OnStar Call button.
  2. Verify that your voice is heard clearly by the OnStar Call center.
  • If your voice can not be heard clearly

Refer to OnStar Microphone Malfunction

  • If your voice can be heard clearly
  1. Verify that the system responds appropriately to all voice commands by pressing the voice command button and attempting to operate the system using multiple voice commands.
  • If the OnStar system does not respond to any voice commands

Replace the K73 Telematics Communication Interface Control Module

  • If the OnStar system responds to some, but not all voice commands

Refer to OnStar Description and Operation for tips on proper pronunciation

  • If the OnStar system responds to all voice commands
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair procedure.

Control Module References for telematics communication interface control module replacement, programming, and setup.

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