Buick Encore Owners & Service Manuals

Buick Encore: Cruise Control - Diagnostic information and procedures

Buick Encore 2012-2019 Service Manual / Accessories & Equipment / Cruise Control / Cruise Control - Diagnostic information and procedures

DTC B3794, P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A-P155C, OR P162C: Cruise control malfunction

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

DTC B3794, P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A-P155C, OR P162C: CRUISE CONTROL 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 B3794 08

Cruise Control Function Request Circuit

DTC B3794 61

Cruise Control Function Request Circuit

DTC P0564

Cruise Control Multifunction Switch Circuit

DTC P0565

Cruise Control Switch Circuit

DTC P0567

Cruise Control Resume Switch Circuit

DTC P0568

Cruise Control Set Switch Circuit

DTC P056C

Cruise Control Cancel Switch Circuit

DTC P0580

Cruise Control Multifunction Switch Circuit Low Voltage

DTC P0581

Cruise Control Multifunction Switch Circuit High Voltage

DTC P155A

Cruise Control Switch State Undetermined

DTC P155B

Cruise Control Set/Coast Switch 2 Circuit

DTC P155C

Cruise Control Resume/Acceleration Switch 2 Circuit

DTC P162C

Vehicle Speed Limiting/Warning Switch Circuit

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The cruise control switch is an input to the body control module (BCM). The BCM monitors the cruise control on/off, set/coast, resume/accelerate and cancel switches via the cruise control switch signal circuit in order to detect when the driver has requested to perform a cruise control function. The BCM detects a specific voltage signal on the cruise control switch signal circuit when a switch is applied. The engine control module (ECM) receives the requested cruise control switch function from the BCM via a serial data message.

Conditions for Running the DTC

  • The cruise switch is ON.
  • The ignition is ON.

Conditions for Setting the DTC

B3794 08

The BCM detects an invalid voltage signal on the cruise control switch signal circuit for 1 second.

B3794 61

Stuck switch for either Resume/Accel or Set/Coast button for 60 seconds.

P0564, P0565, P0567, P0568, P056C

  • The BCM detects an invalid voltage signal on the cruise control switch signal circuit for greater than 2 seconds and sends a serial data message to the ECM. The ECM sets these DTCs when the message is received.
  • The ECM runs this diagnostic continuously.

P0580, P0581

  • The ECM detects an invalid voltage signal on the cruise control switch signal circuit.
  • The above condition is present for greater than 2 seconds.
  • The ECM runs this diagnostic continuously.

P155A

The ECM is unable to determine the state of the cruise control switch.

P162C

The ECM is unable to determine the state of the vehicle speed limiting switch.

Actions Taken When the DTC Sets

B3794

  • The malfunction indicator lamp (MIL) will not illuminate.
  • The cruise control system is disabled.

P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A, P162C

DTCs P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A and P162C are type C DTCs

Conditions for Clearing the DTC

B3794

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A, P162C

DTCs P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A and P162C are type C DTCs.

Reference Information

Schematic Reference

Cruise Control Schematics (Encore), Cruise Control 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

Cruise Control 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 the scan tool ECM Cruise Control Switch Status parameter changes between Off and On, Resume and Set when switching between each position on the cruise control switch.

If the parameter does not change

Refer to Circuit/System Testing.

If the parameter changes

  1. All OK.

Circuit/System Testing

NOTE:

  • An open ignition circuit or fuse before the control module will cause communication DTCs or power mode mismatch DTCs to set against or in the control module. This failure mode will be diagnosed in the no communications diagnostic procedure or power mode mismatch.
  • This test assumes the ignition circuit has a driver that will open under a high current condition before the fuse opens.
  • The driver can open under normal conditions such as battery run down protection or a retained accessory power mode.
  1. Ignition OFF, disconnect the harness connector at the S70L Steering Wheel Controls Switch-Left, ignition ON.
  2. Verify a test lamp illuminates between the ignition circuit terminal 1 and ground.

If the test lamp does not illuminate

  1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
  2. Test for greater than 100 ohms between the ignition circuit and ground.
  • If 100 ohms or less, repair the short to ground on the circuit.
  • If greater than 100 ohms
  1. Test for less than 2 ohms in the ignition circuit end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, test or replace the K9 Body Control Module.

If the test lamp illuminates

  1. Verify the scan tool ECM Cruise Control Switch Status parameter is Off.

If not Off

  1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON.
  2. Test for less than 1 V between the signal circuit terminal 3 and ground.
  • If 1 V or greater, repair the short to voltage on the circuit.
  • If less than 1 V, replace the K9 Body Control Module.

If Off

  1. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ignition circuit terminal 1.
  2. Verify the scan tool ECM Cruise Control parameter is Disabled.

If not Error

  1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
  2. Test for infinite resistance between the signal circuit terminal 9 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 K9 Body Control Module.

If Error

  1. Test or replace the S70L Steering Wheel Controls Switch-Left.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM replacement, programming and setup.

DTC P0572 OR P0573: Brake 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 P0572

Brake Switch Circuit 1 Low Voltage

DTC P0573

Brake Switch Circuit 1 High Voltage

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The stop lamp switch signal circuit is a B+ input from the body control module (BCM) to the engine control module (ECM). The ECM monitors the stop lamp switch circuit to detect when the brake pedal has been applied. The BCM monitors the brake pedal position sensor to determine when the brake pedal is applied. When the brake pedal is applied, the BCM supplies B+ on the stop lamp switch signal circuit and also sends a serial data message to the ECM indicating that the brake pedal has been applied.

Conditions for Running the DTC

  • The engine is running.
  • Battery voltage is greater than 11.5 V.
  • Brakes applied.

Conditions for Setting the DTC

P0572

This DTC will set when the ECM detects a short to ground or an open on the discrete brake signal circuit when the serial data message from the BCM indicates the brakes are applied. This diagnostic will run when the serial data message and the voltage signal on the brake switch signal circuit do not match for 8 out 10 times, and the condition is present for greater than 2 s.

P0573

This DTC will set when the ECM detects a short to voltage on the discrete brake signal circuit when the serial data message from the BCM indicates the brakes are not applied. This diagnostic will run when the serial data message and the voltage signal on the brake switch signal circuit do not match for 8 out 10 times, and the condition is present for greater than 2 s.

Actions Taken When the DTC Sets

  • The malfunction indicator lamp (MIL) will not illuminate.
  • The cruise control system is disabled.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Cruise Control Schematics (Encore), Cruise Control 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

Cruise Control 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 X1 harness connector at the K20 Engine Control Module, ignition ON.
  2. Connect a test lamp between the signal circuit terminal 57 and ground.
  3. Verify the test lamp turns ON and OFF when pressing and releasing the brake pedal.

If the test lamp is always OFF

  1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
  2. Test for infinite resistance between the signal circuit and ground.
  • If not 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 K9 Body Control Module.

If the test lamp is always ON

  1. Ignition OFF, disconnect the harness connector at the K9 Body 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 K9 Body Control Module.

If the test lamp turns ON and OFF

  1. Replace the K20 Engine Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM or ECM replacement, programming, and setup.

DTC P0575: Cruise control switch signal message counter incorrect

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 P0575

Cruise Control Switch Signal Message Counter Incorrect

Circuit/System Description

When a cruise control function switch is activated, the body control module (BCM) detects a predetermined voltage. The BCM sends a serial data message to the engine control module (ECM) indicating the function that has been requested.

Conditions for Running the DTC

  • The ignition is ON.
  • The vehicle speed is greater than 40 km/h (25 MPH) and the cruise control is engaged.

Conditions for Setting the DTC

  • The ECM receives an invalid cruise control switch status serial data message from the BCM.
  • This diagnostic runs continuously.

Actions Taken When the DTC Sets

DTC P0575 is a type C DTC.

Conditions for Clearing the DTC

DTC P0575 is a type C DTC.

Reference Information

Schematic Reference

Cruise Control Schematics (Encore), Cruise Control 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

Cruise Control Description and Operation

Electrical Information Reference

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON.
  2. Verify that no DTCs are set, except DTC P0575.

If any other DTC is set, except DTC P0575

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

If only DTC P0575 is set

  1. Replace the K9 Body Control Module.
  2. Verify DTC P0575 does not set when operating the vehicle within the Conditions for Running the DTC.

If the DTC sets

Replace the K20 Engine Control Module.

If the DTC does not set

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM or ECM replacement, programming, and setup.

DTC P0703: BRAKE SWITCH SIGNAL MESSAGE COUNTER INCORRECT

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 P0703

Brake Switch Signal Message Counter Incorrect

Circuit/System Description

The body control module (BCM) monitors the brake pedal position sensor. When the brake pedal is applied, the BCM detects a predetermined voltage signal. The BCM sends a serial data message to the engine control module (ECM) indicating the status of the stop lamps.

Conditions for Running the DTC

The engine is ON.

Conditions for Setting the DTC

  • The ECM receives an invalid brake pedal status serial data message from the BCM.
  • This diagnostic runs continuously.

Actions Taken When the DTC Sets

  • The malfunction indicator lamp (MIL) will not illuminate.
  • The cruise control system is disabled.

Conditions for Clearing the DTC

  • The condition responsible for setting the DTC no longer exists.
  • A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Cruise Control Schematics (Encore), Cruise Control 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

Cruise Control 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 no DTCs are set, except DTC P0703.

If any other DTC is set, except DTC P0703

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

If only DTC P0703 is set

  1. Replace the K9 Body Control Module.
  2. Verify DTC P0703 does not set when operating the vehicle within the conditions for running the DTC.

If the DTC sets

Replace the K20 Engine Control Module.

If the DTC does not set

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM or ECM replacement, programming, and setup.

SYMPTOMS - CRUISE CONTROL

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

  1. Before using the symptom diagnostic table, perform the Diagnostic System Check - Vehicle in order to verify the following conditions:
  • There are no DTCs set.
  • The module can communicate via the serial data.
  1. Review the system operation in order to understand the system functions. Refer to Cruise Control Description and Operation.

Visual/Physical Inspection

  • Inspect for aftermarket devices which can affect the operation of the Cruise Control System. Refer to Checking Aftermarket Accessories .
  • Inspect the accessible system components or the visible system components for obvious damage or for obvious conditions which can 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:

  • Cruise Control Malfunction - DTC B3794, P0564, P0565, P0567, P0568, P056C, P0580, P0581, P155A-P155C, or P162C
  • Cruise Control Indicator Malfunction

Cruise control indicator 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 instrument cluster illuminates the cruise control engaged indicator based on serial data messages received from the engine control module (ECM). The indicator is commanded ON when the cruise control system is controlling vehicle speed, and turned OFF with the system disengaged.

Reference Information

Schematic Reference

Cruise Control Schematics (Encore), Cruise Control 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

Cruise Control 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 the cruise control indicator turns ON and OFF when commanding the All Indicators ON and OFF with a scan tool.

If the indicator does not turn ON and OFF

Replace the P16 Instrument Cluster.

If the indicator turns ON and OFF

  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for instrument cluster replacement, programming and setup.

Repair instructions

CRUISE CONTROL SWITCH REPLACEMENT

Fig. 3: Cruise Control Switch
Fig. 3: Cruise Control Switch

Cruise Control Switch Replacement

Cruise Control Switch Replacement

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