Buick Encore Owners & Service Manuals

Buick Encore: Engine Heating and Cooling - Diagnostic information and procedures

Buick Encore 2012-2019 Service Manual / Engine / Engine Heating and Cooling / Engine Heating and Cooling - Diagnostic information and procedures

DTC P00B3 OR P00B4 (2H0 OR LUJ): Radiator coolant temperature (RCT) sensor

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 Descriptors

DTC P00B3

Radiator Coolant Temperature (RCT) Sensor Circuit Low Voltage

DTC P00B4

Radiator Coolant Temperature (RCT) Sensor Circuit High Voltage

Diagnostic Fault Information

Diagnostic Fault Information

Typical Scan Tool Data

Radiator Coolant Temperature Sensor

Radiator Coolant Temperature Sensor

Circuit/System Description

NOTE: The radiator coolant temperature sensor is referred to as B34B Engine Coolant Temperature Sensor 2 in schematics and other areas.

The radiator coolant temperature (RCT) sensor is a variable resistor that measures the temperature of the engine coolant in the radiator. This diagnostic checks for an open, short to ground or an intermittent circuit condition between the engine control module (ECM) and RCT sensor.

The following table illustrates the difference between temperature, resistance, and voltage:

Circuit/System Description

Conditions for Running the DTC

P00B3

  • The engine run time is greater than 10 s.
  • The intake air temperature (IAT) is colder than 70ºC (158ºF).
  • The DTC runs continuously when the above conditions are met.

P00B4

  • The engine run time is greater than 60 s.
  • The intake air temperature (IAT) is warmer than -7ºC (19ºF).
  • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P00B3

The ECM detects that the RCT sensor is warmer than 149ºC (300ºF) for greater than 10 s.

P00B4

NOTE: The scan tool only displays to -40ºC (-40ºF).

The ECM detects that the RCT sensor is colder than -60ºC (-76ºF) for greater than 10 s.

Action Taken When the DTC Sets

DTC P00B3 and P00B4 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTC P00B3 and P00B4 are Type B DTCs.

Diagnostic Aids

NOTE:

The engine coolant temperature (ECT) sensor is mounted on the engine and the radiator coolant temperature (RCT) sensor is mounted on the radiator.

  • As the thermostat opens, the RCT sensor temperature should rise steadily, then stabilize once the thermostat opens completely.
  • Test the RCT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor.
  • If the vehicle has sat for greater than 8 hours, the ECT sensor and the RCT sensor values should display within 3ºC (5ºF).

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

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 the scan tool Radiator Coolant Temperature Sensor parameter is between -39 to + 120ºC (-38 to +248ºF) and changes with engine run time.
  • If not between -39 to + 120ºC (-38 to +248ºF) or does not change

Refer to Circuit/System Testing.

  • If between -39 to + 120ºC (-38 to +248ºF) and changes
  1. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  2.  Verify the DTC does not set.
  • If the DTC sets

Refer to Circuit/System Testing.

  • If the DTC does not set
  1. All OK.

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 5 ohms between the low reference circuit terminal 2 and ground.
  • If 5 ohms or greater
  1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
  2. Test for less than 2 ohms in the low 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 K20 Engine Control Module.
  • If less than 5 ohms
  1. Ignition ON.
  2. Verify the scan tool Radiator Coolant Temperature Sensor parameter is colder than -39ºC (-38ºF).
  • If warmer than -39ºC (-38ºF)
  1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
  2. Test for infinite resistance between the signal circuit terminal 1 and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the K20 Engine Control Module.
  • If colder than -39ºC (-38ºF)
  1. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2.
  2. Verify the scan tool Radiator Coolant Temperature sensor parameter is warmer than 137ºC (280ºF).
  • If colder than 137ºC (280ºF)
  1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
  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 K20 Engine Control Module.
  • If warmer than 137ºC (280ºF)
  1. Test or replace the B34B Engine Coolant Temperature Sensor.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor.
  2. Test the RCT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance table. The resistance values should be in range of the table values.
  • If not within the specified range
  • Replace the B34B Engine Coolant Temperature Sensor.
  • If within the specified range
  1. Test for infinite resistance between each terminal and the sensor housing.
  • If less than infinite resistance

Replace the B34B Engine Coolant Temperature Sensor.

  • If infinite resistance
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  • Engine Coolant Temperature Sensor Replacement (Water Outlet) , Engine Coolant Temperature Sensor Replacement (Radiator) for radiator coolant temperature sensor replacement.
  • Engine Control Module Replacement for engine control module replacement, setup, and programming.

DTC P00B6 (2H0 OR LUJ): Radiator coolant temperature (RCT) Sensor

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 P00B6

Radiator Coolant Temperature (RCT)-Engine Coolant Temperature (ECT) Not Plausible

Diagnostic Fault Information

Diagnostic Fault Information

Typical Scan Tool Data

Radiator Coolant Temperature Sensor

Radiator Coolant Temperature Sensor

Circuit Description

The engine coolant temperature sensor is a variable resistor that measures the temperature of the engine coolant in the radiator. The engine control module (ECM) supplies 5 volts to the engine coolant temperature signal circuit and supplies a ground to the low reference circuit. The purpose of this diagnostic is to determine if the input from the RCT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the engine is OFF. If the required engine OFF time is met at start-up, the ECM will compare the temperature difference between the actual measured RCT and ECT sensors.

The following table illustrates the difference between temperature, resistance, and voltage:

Circuit Description

Conditions for Running the DTC

  • DTCs P00B3, P00B4, P00B6, P0112, P0113, P0117, P0118, P0502, P0503 or P2610 are not set.
  • The vehicle has been OFF for greater than 8 hours before vehicle ON.
  • The vehicle is ON, or the engine is running.
  • The intake air temperature (IAT) is warmer than -7ºC (19ºF).
  • The fuel level is greater than 10 percent.
  • The DTC runs once per ignition cycle when the above conditions are met.

Conditions for Setting the DTC

The ECM determines the absolute difference of temperature between the RCT start up temperature and ECT start up temperature is greater than 20ºC (68ºF) .

Action Taken When the DTC Sets

DTC P00B6 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P00B6 is a Type B DTC.

Diagnostic Aids

  • As the thermostat opens, the radiator coolant temperature sensor signal should rise steadily, then stabilize once the thermostat opens completely.
  • Inspect for the correct operation of the engine cooling system and verify the correct coolant level.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

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. Engine running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P0117, P0118, P0597, P0598, or P0599 should not be set.
  • If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
  1. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks.

    Refer to Cooling System Draining and Filling, and Loss of Coolant.

  2. Engine idling for 15 minutes with the A/C OFF.

NOTE:

Depending on ambient temperature, it may take up to 4 minutes for the temperatures to equalize.

  1. Command the engine coolant thermostat heater to 100 percent with a scan tool. Increase the engine speed to 3,000 RPM. Observe the scan tool radiator coolant temperature sensor and ECT sensor parameters. The radiator coolant temperature sensor and the ECT sensor parameters should be within 20ºC (68ºF).
  2. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Circuit/System Testing

  1. Vehicle OFF, disconnect the harness connector at the B34B engine coolant temperature sensor.
  2. Vehicle OFF, all systems OFF. This may take up to 2 minutes for all vehicle systems to power down.

    Test for less than 5 ohms between the low reference circuit terminal 1 and ground.

  • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  1. Vehicle ON, verify the scan tool Radiator Coolant Temperature Sensor parameter is at -40ºC (-40ºF).
  • If warmer than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 engine control module.

NOTE: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.

  1. Install a 1 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Radiator Coolant Temperature Sensor parameter is at 140ºC (284ºF).
  • If less than specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  1. If all circuits test normal, test or replace the B34B engine coolant temperature sensor.

Component Testing

  1. Vehicle OFF, remove the B34B engine coolant temperature sensor.

NOTE: A thermometer can be used to the used to test the sensor off the vehicle.

  1. Test the engine coolant temperature sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance table and verify that the resistance is within 5 percent of the specification.
  • If not within the specified range, replace the B34B engine coolant temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  • Engine Coolant Temperature Sensor Replacement (Water Outlet) , Engine Coolant Temperature Sensor Replacement (Radiator)
  • Engine Control Module Replacement for ECM replacement, setup, and programming

DTC P00B7 (2H0 OR LUJ): Engine coolant flow insufficient

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 P00B7

Engine Coolant Flow Insufficient

Diagnostic Fault Information

Diagnostic Fault Information

Diagnostic Fault Information

Typical Scan Tool Data

Radiator Coolant Temperature Sensor

Radiator Coolant Temperature Sensor

Circuit Description

The engine control module (ECM) monitors the temperature of the engine radiator coolant. The ECM controls the thermostat with a pulse width modulated (PWM) signal. The ECM compares the radiator coolant temperature to the engine coolant temperature in order to determine if there sufficient coolant flow through the thermostat.

Conditions for Running the DTC

  • DTCs P00B3, P00B4, P00B6, P0116, P0117, and P0118 are not set.
  • The engine run time is greater than 5 m.

OR

  • The engine coolant temperature is greater than 105ºC (221ºF).
  • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

NOTE:

The scan tool display range is between -40 and + 150ºC (-40 and +302ºF).

The ECM detects the difference between the RCT sensor and the ECT sensor is greater than 30ºC (86ºF) when the ECT sensor is warmer than 117ºC (242ºF) for greater than 5 s.

Action Taken When the DTC Sets

DTC P00B7 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P00B7 is a Type B DTC.

Diagnostic Aids

  • The thermostat has a mechanical fail-safe in case of an electrical condition with the thermostat heater.

    The mechanical thermostat will open at approximately 80ºC (176ºF). The mechanical thermostat will cycle from approximately 85ºC (185ºF) to approximately 102ºC (215ºF).

  • A resistance condition in the RCT sensor circuits may cause this DTC. This condition results in a greater voltage on the RCT sensor signal circuit, which is interpreted by the ECM as a colder RCT

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling Schematics (Encore)

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. Engine Running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P00B6, P0117, P0118, P0597, P0598, and P0599 should not be set.
  • If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis
  1. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks.

    Refer to Cooling System Draining and Filling, and Loss of Coolant.

  2. Verify the engine cooling fan operates. Refer to Cooling Fan Inoperative (LUJ or LUV), Cooling Fan Inoperative (2H0).
  3. Engine idling for 15 minutes with the A/C OFF.

NOTE: Depending on ambient temperature, it may take up to 4 minutes for the temperature to decrease less than the specified value.

  1. Command the Engine Coolant Thermostat Heater to 100 percent with a scan tool. Increase the engine speed to 3,000 RPM. Observe the scan tool ECT sensor parameter. The temperature should decrease to less than 85ºC (185ºF).
  2. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Circuit/System Testing

  1. Vehicle OFF, inspect the cooling system for the conditions below. Refer to Symptoms - Engine Cooling.
  • Weak coolant solution
  • Obstructed radiator air flow or bent radiator fins
  • Blocked cooling system passages
  • Radiator hoses that are restricted, collapsed, or deteriorated
  • Damaged water pump and or belt
  • Loss of cooling system pressure
  • Leaking surge tank cap
  • Radiator hoses
  • Cylinder head or an engine block that is cracked or plugged
  • If you find any of the above conditions, repair as necessary.
  1. If all conditions test normal, replace the E41 engine coolant thermostat heater.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Engine Coolant Thermostat Replacement (2H0, LDE, LFH), Engine Coolant Thermostat Replacement (LUV, LUJ)

DTC P0480 OR P0481 (2H0): Cooling fan relay 1/2 control 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 P0480

Cooling Fan Relay 1 Control Circuit

DTC P0481

Cooling Fan Relay 2 Control Circuit

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The engine cooling fan system is composed of one cooling fan, 2 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes 1 resistor mounted in the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.

Conditions for Running the DTC

  • The ignition voltage is 11-18 volts.
  • The engine speed is 400 RPM or greater.
  • The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
  • The DTCs run continuously when the conditions above are met.

Conditions for Setting the DTC

The commanded state of the ECM driver and the actual state of the control circuit do not match for greater than 5 seconds.

Action Taken When the DTC Sets

DTCs P0480 and P0481 are Type C DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0480 and P0481 are Type C DTCs.

Diagnostic Aids

  • The ECM has the capability of providing command to the fan relays even when a scan tool output control is being used. Always refer to the fan control command parameters on the scan tool to know which fans are being commanded ON by the ECM.
  • The scan tool cooling fan output control operates as follows:
  • Cooling Fan Relay 1 operates the fan at low speed
  • Cooling Fan Relay 2 operates the fan at a high speed
  • When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

Electrical Information Reference

  • Electrical Center Identification Views (Encore) , Electrical Center Identification Views (Encore)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV), Cooling Fan Description and Operation (2H0)

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)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON.
  2. Verify an audible click is heard or felt from each cooling fan relay when commanding the cooling fan ON and OFF with a scan tool.
  • If a click is not heard or felt at each of the relays

Refer to Circuit/System Testing.

  • If a click is heard or felt at each of the relays
  1. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  2. Verify the DTC does not set.
  • If the DTC sets

Refer to Circuit/System Testing.

  • If the DTC does not set
  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the cooling fan relays listed below:
  • KR20C Cooling Fan Low Speed Relay
  • KR20D Cooling Fan High Speed Relay

NOTE:

The following test must be performed on each of the relay coil ignition circuits.

  1. Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit terminal listed below and ground:
  • KR20C Cooling Fan Low Speed Relay terminal 85
  • KR20D Cooling Fan High Speed Relay terminal 85
  • If the test lamp does not illuminate and the circuit fuse is good
  1. Ignition OFF, remove the test lamp.
  2. Test for less than 2 ohms in the ignition circuit of the appropriate cooling fan relay, end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
  • If the test lamp does not illuminate and the circuit fuse is open
  1. Ignition OFF, remove the test lamp.
  2. Test for infinite resistance between the relay coil ignition circuits listed below and ground:
  • KR20C Cooling Fan Low Speed Relay terminal 85
  • KR20D Cooling Fan High Speed Relay terminal 85
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance, test all of the appropriate relays for a shorted condition and replace as necessary.
  • If the test lamp illuminates
  1. Ignition OFF, remove the test lamp, ignition ON.

NOTE: The following tests must be performed on the two fan relay control circuits.

  1. Connect a DMM, set on the diode setting, between a control circuit terminal listed below and ground:
  • KR20C Cooling Fan Low Speed Relay terminal 86
  • KR20D Cooling Fan High Speed relay terminal 86
  1. Verify the DMM reading is greater than 2.5 V or displays O.L.
  • If 2.5 V or less
  1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
  2. Test for infinite resistance between the appropriate relay coil control circuit and ground
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the K20 Engine Control Module.
  • If greater than 2.5 V or displays O.L.

NOTE: The following test must be performed on the two fan relay circuits.

  1. Verify the DMM reading is less than 1 V when commanding the Cooling Fan Relays ON with a scan tool.
  • If 1 V or greater
  1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module, ignition ON.
  2. Test for less than 1 V between the appropriate cooling fan relay control 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 appropriate cooling fan relay 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 K20 Engine Control Module.
  • If less than 1 V
  1. Test or replace the appropriate cooling fan relay.

Component Testing

  1. Ignition OFF.
  2. Disconnect a cooling fan relay.
  3. Test for 70-110 ohms between terminals 85/2 and 86/1.
  • If less than 70 ohms or greater than 110 ohms

Replace the cooling fan relay.

  • If between 70-110 ohms
  1. Test for infinite resistance between following terminals:
  • 30/3 and 86/1
  • 30/3 and 87/5
  • 30/3 and 85/2
  • 85/2 and 87/5
  • If less than infinite resistance

Replace the cooling fan relay.

  • If infinite resistance
  1. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
  2. Install a jumper wire between relay terminal 86/1 and ground.
  3. Test for less than 2 ohms between terminals 30/3 and 87/5.
  • If 2 ohms or greater

Replace the cooling fan relay.

  • If less than 2 ohms
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)
  • Control Module References for ECM replacement, programming, and setup

DTC P0480, P0481, P0691, P0692, P0693, OR P0694 (LUJ OR LUV): Cooling fan relay 1/2/3 control 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 P0480

Cooling Fan Relay 1 Control Circuit

DTC P0481

Cooling Fan Relays 2 and 3 Control Circuit

DTC P0691

Cooling Fan Relay 1 Control Circuit Low Voltage

DTC P0692

Cooling Fan Relay 1 Control Circuit High Voltage

DTC P0693

Cooling Fan Relays 2 and 3 Control Circuit Low Voltage

DTC P0694

Cooling Fan Relays 2 and 3 Control Circuit High Voltage

Diagnostic Fault Information

KR20C Cooling Fan Low Speed Relay

KR20C Cooling Fan Low Speed Relay

KR20C Cooling Fan Low Speed Relay

KR20D Cooling Fan High Speed Relay

KR20D Cooling Fan High Speed Relay

KR20E Cooling Fan Speed Control Relay

KR20E Cooling Fan Speed Control Relay

KR20F Cooling Fan Relay

KR20F Cooling Fan Relay

KR20P Cooling Fan Medium Speed Relay

KR20P Cooling Fan Medium Speed Relay

KR20P Cooling Fan Medium Speed Relay

Circuit/System Description

The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

Conditions for Running the DTC

LUV or LFF- ECM with 2 Face Mounted Connectors

  • The ignition voltage is between 11-32 volts.
  • The engine speed is 400 RPM or greater.
  • The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
  • DTCs P0480 and P0481 run continuously when the conditions above are met.

LUJ- ECM with 3 Face Mounted Connectors

  • The ignition voltage is 11 volts or greater.
  • The ECM has commanded the output driver ON and OFF at least once during the ignition cycle.
  • DTCs P0480, P0481, P0691, P0692, P0693, and P0694 run continuously when the conditions above are met.

Conditions for Setting the DTC

The commanded state of the ECM driver and the actual state of the control circuit do not match for greater than 5 seconds.

Action Taken When the DTC Sets

  • DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs - LUV or LFF.
  • DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type C DTCs - LUJ.

Conditions for Clearing the MIL/DTC

  • DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs - LUV or LFF.
  • DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type C DTCs - LUJ.

Diagnostic Aids

  • The ECM has the capability of providing command to the fan relays even when a scan tool output control is being used. Always refer to the scan tool Cooling Fan Relay Command parameters to know which fans are being commanded ON by the ECM.
  • The scan tool cooling fan output control operates as follows:
  • Cooling Fan Relay 1 operates the fan at a low speed
  • Cooling Fan Relay 2 and 3 operates the fan at a medium speed
  • Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
  • When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and test the mating electrical terminals for tightness.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

Electrical Information Reference

  • Electrical Center Identification Views (Encore) , Electrical Center Identification Views (Encore)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV)

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)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON.
  2. Verify an audible click is heard or felt from each cooling fan relay when commanding the cooling fan ON and OFF with a scan tool.
  • If a click is not heard or felt at each of the relays

Refer to Circuit/System Testing.

  • If a click is heard or felt at each of the relays
  1. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  2. Verify the DTC does not set.
  • If the DTC sets

Refer to Circuit/System Testing.

  • If the DTC does not set
  1. All OK

Circuit/System Testing

  1. Ignition OFF, disconnect the cooling fan relays listed below:
  • KR20F Cooling Fan Relay
  • KR20P Cooling Fan Medium Speed Relay
  • KR20D Cooling Fan High Speed Relay

NOTE: The following test must be performed on each of the relay coil ignition circuits.

  1. Ignition ON, verify that a test lamp illuminates between ground and the relay coil ignition circuit terminal listed below:
  • KR20F Cooling Fan Relay terminal 85/2
  • KR20P Cooling Fan Medium Speed Relay terminal 86/1

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

  1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down. Remove the fuse that supplies ignition voltage to the coil side of the cooling fan relays.
  2. Test for less than 2 ohms between the ignition circuit terminal of the appropriate cooling fan relay and the fuse.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
  • If the test lamp does not illuminate and the circuit fuse is open
  1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
  2. Test for infinite resistance between the relay coil ignition circuits listed below and ground:
  • KR20F Cooling Fan Relay terminal 85/2
  • KR20D Cooling Fan High Speed Relay terminal 86/1
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance, test all of the appropriate cooling fan relays for a shorted condition and replace as necessary.
  • If the test lamp illuminates
  1. Ignition OFF, remove the test lamp, ignition ON.

NOTE:

  • The following tests must be performed on all three fan relay control circuits.
  • The Red test lead should be connected to the control circuit.
  1. Connect a DMM, set on the diode setting, between a control circuit terminal listed below and ground:
  • KR20F cooling fan relay terminal 86/1
  • KR20P cooling fan medium speed relay terminal 85/2
  • KR20D cooling fan high speed relay terminal 85/2
  1. Verify the DMM reading is greater than 2.5 V or displays O.L.
  • If 2.5 V or less
  1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down. Disconnect the harness connector X1 at the K20 Engine Control Module.
  2. Test for infinite resistance between the appropriate relay coil control circuit and ground.
  • If less than infinite resistance, repair the short to ground on the circuit.
  • If infinite resistance, replace the K20 Engine Control Module.
  • If greater than 2.5 V or displays O.L.

NOTE: The following test must be performed on all three fan relay circuits.

  1. Verify the DMM reading is less than 1 V when commanding the Cooling Fan Relays ON with a scan tool.
  • If 1 V or greater
  1. Ignition OFF, disconnect the harness connector X1 at the K20 Engine Control Module, ignition ON.
  2. Test for less than 1 V between the appropriate cooling fan relay control 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 appropriate cooling fan relay 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 K20 Engine Control Module.
  • If less than 1 V
  1. Test or replace the appropriate cooling fan relay.

Component Testing

  1. Ignition OFF.
  2. Disconnect a cooling fan relay.
  3. Test for 70-110 ohms between terminals 85/2 and 86/1.
  • If less than or greater than the specified range

Replace the cooling fan relay.

  • If within the specified range
  1. Test for infinite resistance between the following terminals:
  • 30/3 and 86/1
  • 30/3 and 87/5
  • 30/3 and 85/2
  • 85/2 and 87/5
  • If less than infinite resistance

Replace the cooling fan relay.

  • If infinite resistance
  1. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
  2. Install a jumper wire between relay terminal 86/1 and ground.
  3. Test for less than 2 ohms between terminals 30/3 and 87/5.
  • If 2 ohms or greater

Replace the cooling fan relay.

  • If less than 2 ohms
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  • Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)
  • Control Module References for ECM replacement, setup, and programming

DTC P0597-P0599 (2H0 OR LUJ): Engine coolant thermostat heater control 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 Descriptor

DTC P0597

Engine Coolant Thermostat Heater Control Circuit

DTC P0598

Engine Coolant Thermostat Heater Control Circuit Low Voltage

DTC P0599

Engine Coolant Thermostat Heater Control Circuit High Voltage

Diagnostic Fault Information

Diagnostic Fault Information

Circuit/System Description

The engine control module (ECM) controls the pulse width modulated (PWM) thermostat. The thermostat controls coolant flow and regulates the engine operating temperature. Ignition voltage is supplied directly to the thermostat through a fuse. The ECM controls the thermostat by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

Conditions for Running the DTCs

  • The ignition is ON, or the engine is running.
  • The DTCs run continuously once the above condition is met

Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 15 seconds.

Action Taken When the DTC Sets

  • DTCs P0597, P0598, and P0599 are Type B DTCs.
  • The engine control module commands the engine cooling fans ON.

Conditions for Clearing the DTC

DTCs P0597, P0598, and P0599 are Type B DTCs.

Diagnostic Aids

  • A low engine coolant level could cause the thermostat heater to overheat and set a DTC.
  • The thermostat has a mechanical fail-safe in case of an electrical condition with the thermostat heater.

    The mechanical thermostat will open at approximately 80ºC (176ºF). The mechanical thermostat will cycle from approximately 85ºC (185ºF) to approximately 102ºC (215ºF).

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

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. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks.

    Loss of Coolant, and Cooling System Draining and Filling

  • If the coolant level is not correct

Repair as necessary.

  • If the coolant level is correct
  1. Ignition ON.
  2. Verify the parameters listed below do not display Malfunction when commanding the Engine Coolant Thermostat Heater ON and OFF with a scan tool.
  • Engine Coolant Thermostat Heater Control Circuit Low Voltage Test Status
  • Engine Coolant Thermostat Heater Control Circuit Open Test Status
  • Engine Coolant Thermostat Heater Control Circuit High Voltage Test Status
  • If Malfunction is displayed

Refer to Circuit/System Testing.

  • If Malfunction is not displayed
  1. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  2. Verify the DTC does not set.
  • If any DTC sets

Refer to Circuit/System Testing.

  • If the DTC does not set
  1. All OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the E41 Engine Coolant Thermostat Heater, Ignition ON.
  2. Verify that a test lamp illuminates between the ignition circuit terminal 2 and ground.
  • If the test lamp does not illuminate and the circuit fuse is good
  1. Ignition OFF, remove the test lamp.
  2. 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 verify the fuse is not open and there is voltage at the fuse.
  • If the test lamp does not illuminate and the circuit fuse is open
  1. Ignition OFF, remove the test lamp.
  2. Test for infinite resistance between the ignition circuit and ground.
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance, test all the components connected to fuse and replace as necessary.
  • If the test lamp illuminates
  1. Connect a test lamp between the ignition circuit terminal 2 and the control circuit terminal 1, command the Engine Coolant Thermostat Heater to Increase to 100 % and Decrease to 0 % with a scan tool.
  2. Verify that a test lamp turns On and OFF.
  • If the test is always ON
  1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
  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, replace the K20 Engine Control Module.
  • If the test lamp is always OFF
  1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, 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.
  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 K20 Engine Control Module.
  • If the test lamp turns On and OFF
  1. Test or replace the E41 Engine Coolant Thermostat Heater.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  • Engine Coolant Thermostat Replacement (2H0, LDE, LFH), Engine Coolant Thermostat Replacement (LUV, LUJ) for E41 engine coolant thermostat heater replacement
  • Control Module References for engine control module, replacement, programming, and setup.

DTC P2181 (2H0 OR LUJ): Engine cooling system 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 P2181

Engine Cooling System Performance

Circuit/System Description

The engine control module (ECM) monitors temperature difference between the engine coolant temperature (ECT) sensor and the radiator coolant temperature (RCT) sensor during a cold start-up. The purpose of this diagnostic is to analyze the engine coolant thermostat for being stuck open.

Conditions for Running the DTC

  • DTCs P00B3, P00B4, P00B6, P0101, P0102, P0103, P0111, P0112, P0113, P0114, P0116, P0117, or P0118 are not set.
  • The engine run time is between 70 s and 30 min.
  • The engine coolant temperature (ECT) sensor at start-up is between -10ºC to +59ºC (14ºF to 138ºF).
  • The intake air temperature (IAT) sensor is between -7ºC to +60ºC (-4ºF to +140ºF).
  • The airflow into the engine is between 1 to 100 g/s.
  • The DTC runs once per ignition cycle when the above conditions are met.

Conditions for Setting the DTC

The ECM detects the engine coolant thermostat is stuck open for at least 2.5 min.

Action Taken When the DTC Sets

DTC P2181 is a Type B DTC

Conditions for Clearing the DTC

DTC P2181 is a Type B DTC

Diagnostic Aids

  • Insufficient vehicle interior heating is an indication of improper thermostat operation.
  • The scan tool Desired ECT Sensor and the ECT Sensor parameters should be within 5ºC (9ºF) when the engine is at operating temperature.
  • A resistance condition in the ECT sensor circuits may cause this DTC. This condition results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

Cooling System 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. Engine running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P00B6, P0117, or P0118 should not be set.
  • If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
  1. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks.

    Refer to Cooling System Draining and Filling, and Loss of Coolant.

NOTE: Depending on ambient temperature, it may take up to 4 min for the temperature to increase greater than the specified value.

  1. Engine idling for 15 min with the A/C OFF. Verify the engine cooling fan is not ON at all times.
  2. Command the Engine Coolant Thermostat Heater to 0 % with a scan tool. Increase the engine speed to 3,000 RPM. Observe the scan tool ECT sensor parameter. The temperature should increase to greater than 102ºC (215ºF).
  • If less than the specified value, replace the E41 engine coolant thermostat heater.
  1. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Engine Coolant Thermostat Replacement (2H0, LDE, LFH), Engine Coolant Thermostat Replacement (LUV, LUJ)

SYMPTOMS - ENGINE COOLING

Important Preliminary Inspections Before Starting

Before using the Symptom diagnosis, perform the following:

  • Perform Diagnostic System Check - Vehicle and verify all of the following items:
  • Engine control module (ECM) and malfunction indicator lamp (MIL) are operating correctly.
  • There are no diagnostic trouble codes (DTCs) stored.
  • Scan tool data is within a normal operating range.
  • Verify the customer concern.
  • Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.
  • Locate the correct symptom. Perform the tests and inspections associated with the symptom.

Review the entire cooling system operation in order to familiarize yourself with the system functions. Refer to Cooling Fan Description and Operation (LUJ or LUV), Cooling Fan Description and Operation (2H0), and Cooling System Description and Operation.

Visual/Physical Inspection

CAUTION: Use the connector test adapter kit EL-35616-F for any test that requires probing the following items:

  • The control module harness connectors
  • The electrical center fuse/relay cavities
  • The component terminals
  • The component harness connector

Using this kit will prevent damage caused by the improper probing of connector terminals.

Several of the symptom procedures call for a careful visual and physical inspection. This can lead to correcting a condition without further tests and can save time. This inspection should include the following:

  • Ensure that the control module grounds are clean, tight, and correctly located.
  • Inspect cooling system hoses and pipes for splits, kinks, and improper connections. Inspect thoroughly for any type of leak or restriction.
  • Inspect for a dirty or restricted radiator or HVAC condenser.
  • Inspect for aftermarket devices which could affect the operation of the cooling system.
  • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
  • Inspect the coolant recovery reservoir for proper coolant level.

Identifying Intermittent Conditions

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movement of a component. Refer to the following for a list to help isolate an intermittent condition:

  • Water intrusion in connectors, terminals, or components
  • Poor connector mating
  • Terminal contact
  • High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
  • Harness' that are routed too tight, or chaffed circuits
  • High or low ambient temperatures
  • High or low engine coolant temperatures
  • High underhood temperatures
  • Heat build up in components or circuits due to circuit resistance, poor terminal contact, or high electrical load
  • High or low system voltage
  • High vehicle load conditions
  • Rough road surface
  • Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
  • Incorrect installation of non-factory, aftermarket, or after factory add on accessories

If an intermittent fault is detected, refer to Testing for Intermittent Conditions and Poor Connections for specific strategies in diagnosing intermittent conditions.

Symptom List

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

  • Cooling Fan Always On (LUJ or LUV), Cooling Fan Always On (2H0)
  • Cooling Fan Inoperative (LUJ or LUV), Cooling Fan Inoperative (2H0)
  • Engine Overheating
  • Loss of Coolant
  • Thermostat Diagnosis
  • Engine Fails To Reach Normal Operating Temperature

Cooling fan always on  (LUJ OR LUV)

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 the diagnostic category.

Circuit/System Description

The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

Diagnostic Aids

  • The scan tool cooling fan output control operates as follows:
  • Cooling Fan Relay 1 operates the fan at a low speed
  • Cooling Fan Relay 2 and 3 operates the fan at a medium speed
  • Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
  • Certain resistance conditions with intake air temperature (IAT) or engine coolant temperature (ECT) sensors may cause unwarranted cooling fan activation. If the ECM is commanding the cooling fans ON for no apparent reason and without any component or system DTCs set, the IAT or ECT sensor may be skewed. If this condition is suspected, refer to the Temperature Versus Resistance tables in Specifications of the appropriate engine controls subsection.
  • If the cooling fan operates at high speed when the ECM is requesting medium speed operation, test or replace the KR20E Cooling Fan Speed Control Relay.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

Electrical Information Reference

  • Electrical Center Identification Views (Encore) , Electrical Center Identification Views (Encore)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV)

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 there are no cooling system DTCs set.
  • If any DTCs are set

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

  • If no DTCs are set
  1. Verify the scan tool parameters listed below display OFF.
  • Cooling Fan Relay 1 Command
  • Cooling Fan Relays 2 and 3 Command
  • If a scan tool parameter displays ON

Refer to Diagnostic Aids and Symptoms - Engine Cooling for further diagnosis

  • If both scan tool parameters display OFF
  1. Verify that the fan is not activated.
  • If the fan is operating

Refer to Circuit/System Testing.

  • If the fan is OFF
  1. All OK.

Circuit/System Testing

NOTE: The following tests must be performed on each cooling fan relay.

  1. Ignition OFF, disconnect each cooling fan relay one at a time, in the order listed below, ignition ON:
  • KR20F Cooling Fan Relay
  • KR20C Cooling Fan Low Speed Relay
  • KR20P Cooling Fan Medium Speed Relay
  • KR20D Cooling Fan High Speed Relay
  1. Verify that the cooling fan is not activated after each relay is removed.
  • If the cooling fan is ON with all of the listed relays removed
  1. Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor, ignition ON.
  2. Test for less than 1 V between the relay controlled output circuit terminal listed below and ground:
  • KR20C Cooling Fan Low Speed Relay terminal 87/5
  • KR20P Cooling Fan Medium Speed Relay terminal 87/5
  • KR20D Cooling Fan High Speed Relay terminal 87/5
  • If 1 V or greater, repair the short to voltage in the appropriate circuit.
  • If the cooling fan is OFF after a listed relay is removed
  1. Replace the appropriate cooling fan relay.

Component Testing

  1. Ignition OFF.
  2. Disconnect a cooling fan relay.
  3. Test for 70-110 ohms between terminals 85/2 and 86/1.
  • If less than or greater than the specified range

Replace the cooling fan relay.

  • If within the specified range
  1. Test for infinite resistance between the following terminals:
  • 30/3 and 86/1
  • 30/3 and 87/5
  • 30/3 and 85/2
  • 85/2 and 87/5
  • If less than infinite resistance

Replace the cooling fan relay.

  • If infinite resistance
  1. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
  2. Install a jumper wire between relay terminal 86/1 and ground.
  3. Test for less than 2 ohms between terminals 30/3 and 87/5.
  • If 2 ohms or greater

Replace the cooling fan relay.

  • If less than 2 ohms
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)

Cooling fan always ON (2H0)

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 engine cooling fan system consists of a cooling fan assembly containing one electric cooling fan. The engine control module (ECM) uses two fan control circuits and a series of two relays to command the fans ON in either high speed or low speed, depending on cooling requirements. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. In low speed, the fan is turned ON at a reduced speed. High speed has the fan turned ON at full speed.

Diagnostic Aids

  • The scan tool cooling fan output control operates as follows:
  • Cooling Fan Relay 1 operates both fans at a low speed
  • Cooling Fan Relay 2 operates one fan at a high speed
  • Certain resistance conditions with IAT or ECT sensors may cause unwarranted cooling fan activation. If the ECM is commanding the cooling fans ON for no apparent reason and without any component or system DTCs set, the IAT or ECT sensor may be skewed. If this condition is suspected, refer to the temperature versus resistance tables in the appropriate Engine Controls subsection.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

Electrical Information Reference

  • Electrical Center Identification Views (Encore) , Electrical Center Identification Views (Encore)

Description and Operation

Cooling Fan Description and Operation (2H0)

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 P0480 or P0481 is not set.
  • If any of the DTCs are set

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

  • If none of the DTCs are set
  1. Verify the scan tool parameters listed below display OFF:
  • Cooling Fan Relay 1 Command
  • Cooling Fan Relays 2 Command
  • If a scan tool parameter displays ON

Refer to Diagnostic Aids and Symptoms - Engine Cooling for further diagnosis.

  • If both scan tool parameters display OFF
  1. Verify that the fan is not activated.
  • If a fan is operating

Refer to Circuit/System Testing.

  • If the fan is OFF
  1. All OK.

Circuit/System Testing

Cooling Fan Always ON

  1. Ignition OFF, disconnect the KR20C Cooling Fan Low Speed Relay and KR20D Cooling Fan High Speed Relay one at a time, ignition ON.
  2. Verify that the cooling fan is OFF.
  • If the cooling fan is ON after both relays are removed
  1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor, ignition ON.
  2. Test for less than 1 V between the appropriate output control circuit terminal 87 and ground.
  • If 1 V or greater, repair the short to voltage in the circuit.
  • If the cooling fan is OFF after both relays are removed
  1. Test or replace the appropriate cooling fan relay.

Component Testing

  1. Ignition OFF.
  2. Disconnect a cooling fan relay.
  3. Test for 70-110 ohms between terminals 85/2 and 86/1.
  • If less than 70 ohms or greater than 110 ohms

Replace the cooling fan relay.

  • If between 70-110 ohms
  1. Test for infinite resistance between following terminals:
  • 30/3 and 86/1
  • 30/3 and 87/5
  • 30/3 and 85/2
  • 85/2 and 87/5
  • If less than infinite resistance

Replace the cooling fan relay.

  • If infinite resistance
  1. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
  2. Install a jumper wire between relay terminal 86/1 and ground.
  3. Test for less than 2 ohms between terminals 30/3 and 87/5.
  • If 2 ohms or greater

Replace the cooling fan relay.

  • If less than 2 ohms
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)

Cooling fan inoperative (LUJ OR LUV)

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 engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two resistors. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.

Diagnostic Aids

  • The scan tool cooling fan output control operates as follows:
  • Cooling Fan Relay 1 operates the fan at a low speed
  • Cooling Fan Relay 2 and 3 operates the fan at a medium speed
  • Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
  • When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion. Test the mating electrical terminals for tightness.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

Electrical Information Reference

  • Electrical Center Identification Views (Encore) , Electrical Center Identification Views (Encore)

Description and Operation

Cooling Fan Description and Operation (LUJ or LUV)

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 P0480, P0481, P0691, P0692, P0693, or P0694 is not set.
  • If a DTC is set

Refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LUJ or LUV).

  • If no DTC is set
  1. Verify that the G10 Cooling Fan Motor operates at low, medium, and high speed, when commanding the appropriate cooling fan relays ON and OFF with a scan tool.
  • If the cooling fan does not operate at all speeds

Refer to Circuit/System Testing.

  • If the cooling fan operates at all speeds
  1. All OK.

Circuit/System Testing

Inoperative in All Speeds

  1. Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor.
  2. Verify a test lamp illuminates between the ground circuit terminal 1 and B+.
  • If the test lamp does not illuminate
  1. Ignition OFF, remove the test lamp.
  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 the test lamp illuminates
  1. Test or replace the G10 Cooling Fan Motor. Replace the cooling fan fuses if necessary.

Low, Medium, or High Speed Inoperative

  1. Ignition OFF.
  2. Disconnect the following cooling fan relays, ignition ON:
  • KR20C Cooling Fan Low Speed Relay
  • KR20D Cooling Fan High Speed Relay
  • KR20E Cooling Fan Speed Control Relay
  • KR20F Cooling Fan Relay
  • KR20P Cooling Fan Medium Speed Relay
  1. Verify a test lamp illuminates between ground and each of the cooling fan relay B+ circuit terminals listed below:
  • KR20C Cooling Fan Low Speed Relay terminal 30/3
  • KR20D Cooling Fan High Speed Relay terminal 30/3
  • KR20P Cooling Fan Medium Speed Relay terminal 30/3
  • If the test lamp does not illuminate and the circuit fuse is good
  1. Ignition OFF, remove the test lamp.
  2. Test for less than 2 ohms in the appropriate relay B+ circuit, end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
  • If the test lamp does not illuminate and the circuit fuse is open
  1. Ignition OFF, disconnect the harness connector at the R10 Cooling Fan Resistor.
  2. Test for infinite resistance between the appropriate relay controlled output circuit terminal listed below and ground:
  • KR20C Cooling Fan Low Speed Relay terminal 87/5
  • KR20D Cooling Fan High Speed Relay terminal 87/5
  • KR20P Cooling Fan Medium Speed Relay terminal 87/5
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance, test or replace the G10 Cooling Fan Motor, replace the fuse as necessary.
  • If the test lamp illuminates
  1. Verify a test lamp illuminates between the KR20F Cooling Fan Relay output circuit terminal 87/5 and B+.
  • If the test lamp does not illuminate
  1. Ignition OFF, remove the test lamp.
  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 the test lamp illuminates
  1. Ignition OFF, Install the KR20F Cooling Fan Relay, ignition ON.
  2. Verify a test lamp illuminates between each of the cooling fan relay ignition circuit terminals listed below and ground:
  • KR20C Cooling Fan Low Speed Relay terminal 86/1
  • KR20E Cooling Fan Speed Control Relay terminal 85/2 and 30/3
  • If the test lamp does not illuminate at each terminal
  1. Ignition OFF, remove the test lamp.
  2. Test for less than 2 ohms between the appropriate relay ignition circuit terminal and the fuse.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
  • If the test lamp illuminates at each terminal
  1. Command the cooling fan ON at low speed with a scan tool.
  2. Verify a test lamp illuminates between B+ and each of the relay control circuit terminals listed below:
  • KR20C Cooling Fan Low Speed Relay terminal 85
  • KR20E Cooling Fan Speed Control Relay terminal 86
  • If the test lamp does not illuminate
  1. Ignition OFF, remove the test lamp and disconnect the KR20F Cooling Fan Relay.
  2. Test for less than 2 ohms between the KR20F Cooling Fan Relay terminal 30/3 and the relay control circuit terminals listed below:
  • KR20C Cooling Fan Low Speed Relay terminal 85
  • KR20E Cooling Fan Speed Control Relay terminal 86
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the KR20F Cooling Fan Relay.
  • If the test lamp illuminates
  1. Ignition OFF, install the KR20E Cooling Fan Speed Control Relay, ignition ON.
  2.  Command the cooling fan ON at low speed with a scan tool.
  3.  Verify a test lamp illuminates between the KR20D Cooling Fan High Speed Relay ignition circuit terminal 85/1 and ground.

If the test lamp does not illuminate

  1. Ignition OFF, remove the test lamp and disconnect the KR20E Cooling Fan Speed Control Relay.
  2. Test for less than 2 ohms between the KR20D Cooling Fan High Speed Relay terminal 85/1 and KR20E Cooling Fan Speed Control Relay terminal 87/5.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, replace the KR20E Cooling Fan Speed Control Relay.
  • If the test lamp illuminates
  1. Ignition OFF, install all of the previously removed cooling fan relays. Disconnect the harness connector at the R10 Cooling Fan Resistor, ignition ON.
  2. Command the cooling fan ON at high speed with a scan tool.
  3. Verify a test lamp illuminates between ground and each of the R10 Cooling Fan Resistor circuit terminals listed below:
  • R10 Cooling Fan Resistor low speed circuit terminal 2
  • R10 Cooling Fan Resistor medium speed circuit terminal 3
  • R10 Cooling Fan Resistor high speed circuit terminal 4
  • If the test lamp does not illuminate at each terminal
  1. Ignition OFF, remove the test lamp.
  2. Disconnect the appropriate relay from the list below:
  • KR20C Cooling Fan Low Speed Relay
  • KR20D Cooling Fan High Speed Relay
  • KR20P Cooling Fan Medium Speed Relay
  1. Test for less than 2 ohms in the relay controlled output 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 relay.
  • If the test lamp illuminates at each terminal
  1. Test or replace the G10 Cooling Fan Motor.

Component Testing

Relay Test

  1. Ignition OFF.
  2. Disconnect a cooling fan relay.
  3. Test for 70-110 ohms between terminals 85/2 and 86/1.
  • If less than or greater than the specified range

Replace the cooling fan relay.

  • If within the specified range
  1. Test for infinite resistance between the following terminals:
  • 30/3 and 86/1
  • 30/3 and 87/5
  • 30/3 and 85/2
  • 85/2 and 87/5
  • If less than infinite resistance

Replace the cooling fan relay.

  • If infinite resistance
  1. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
  2. Install a jumper wire between relay terminal 86/1 and ground.
  3. Test for less than 2 ohms between terminals 30/3 and 87/5.
  • If 2 ohms or greater

Replace the cooling fan relay.

  • If less than 2 ohms
  1. All OK.

Cooling Fan Motor Test

  1. Ignition OFF.
  2. Disconnect the harness connector at the R10 Cooling Fan Resistor.
  3. Connect a jumper wire between the R10 Cooling Fan Resistor terminal 1 and ground.
  4. Connect an appropriately fused jumper wire between a R10 Cooling Fan Resistor terminal listed below and B+.
  • R10 Cooling Fan Resistor low speed terminal 2
  • R10 Cooling Fan Resistor medium speed terminal 3
  • R10 Cooling Fan Resistor high speed terminal 4
  1. Verify the G10 Cooling Fan Motor operates when voltage is applied to each terminal.
  • The cooling fan does not operate

Replace the G10 Cooling Fan Motor.

  • The cooling fan operates
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  • Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)
  • Front Compartment Fuse Block Replacement
  • Engine Coolant Fan Replacement (LUJ, LUV)

Cooling fan inoperative (2H0)

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 engine cooling fan system is composed of one cooling fan, 2 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes 1 resistor mounted in the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 2 speeds using two fan control circuits. The ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. Each driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. The ECM will operate the cooling fan at either Low or High speed based on the cooling requirements.

Diagnostic Aids

The scan tool cooling fan output control operates as follows:

  • Cooling Fan Relay 1 operates the fan at a low speed
  • Cooling Fan Relay 2 operates the fan at a high speed

When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling 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

Electrical Information Reference

  • Electrical Center Identification Views (Encore) , Electrical Center Identification Views (Encore)

Description and Operation

Cooling Fan Description and Operation (2H0)

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 P0480, P0481, P0691, P0692, P0693, or P0694 is not set.
  • If a DTC is set

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

  • If no DTC is set
  1. Verify that the cooling fan operates at low and high speed, when commanding the appropriate cooling fan relays ON and OFF with a scan tool.
  • If the cooling fan does not operate at all speeds

Refer to Circuit/System Testing

  • If the cooling fan operates at all speeds
  1. All OK.

Circuit/System Testing

Inoperative in All Speeds

  1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor.
  2. Verify a test lamp illuminates between the ground circuit terminal C and B+.
  • If the test lamp does not illuminate
  1. Ignition OFF, remove the test lamp.
  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 the test lamp illuminates
  1. Test or replace the G10 Cooling Fan Motor. Replace the cooling fan fuses if necessary.

Low or High Speed Inoperative

  1. Disconnect the following cooling fan relays, ignition ON:
  • KR20C Cooling Fan Low Speed Relay
  • KR20D Cooling Fan High Speed Relay
  1. Verify a test lamp illuminates between ground and each of the cooling fan relay B+ circuit terminals listed below:
  • KR20C Cooling Fan Low Speed Relay terminal 30
  • KR20D Cooling Fan High Speed Relay terminal 30
  • If the test lamp does not illuminate and the circuit fuse is good
  1. Ignition OFF, remove the test lamp.
  2. Test for less than 2 ohms in the appropriate relay B+ circuit, end to end.
  • If 2 ohms or greater, repair the open/high resistance in the circuit.
  • If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
  • If the test lamp does not illuminate and the circuit fuse is open
  1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor.
  2. Test for infinite resistance between the appropriate relay controlled output circuit terminal listed below and ground:
  • KR20C Cooling Fan Low Speed Relay terminal 87
  • KR20D Cooling Fan High Speed Relay terminal 87
  • If less than infinite resistance, repair the short to ground in the circuit.
  • If infinite resistance, test or replace the G10 Cooling Fan Motor, replace the fuse as necessary.
  • If the test lamp illuminates
  1. Ignition OFF, install all of the previously removed cooling fan relays. Disconnect the harness connector at the G10 Cooling Fan Motor, ignition ON.
  2. Command the cooling fan ON at high or low speed as appropriate with a scan tool.
  3. Verify a test lamp illuminates between ground and appropriate G10 Cooling Fan Motor circuit terminals listed below:
  • G10 Cooling Fan Motor low speed circuit terminal B
  • G10 Cooling Fan Motor high speed circuit terminal A
  • If the test lamp does not illuminate at each terminal
  1. Ignition OFF, remove the test lamp.
  2. Disconnect the appropriate relay from the list below:
  • KR20C Cooling Fan Low Speed Relay
  • KR20D Cooling Fan High Speed Relay
  1. Test for less than 2 ohms in the relay controlled output 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 relay.
  • If the test lamp illuminate at each terminal
  1. Test or replace the G10 Cooling Fan Motor.

Component Testing

  1. Ignition OFF.
  2.  Disconnect a cooling fan relay.
  3. Test for 70-110 ohms between terminals 85/2 and 86/1.
  • If less than 70 ohms or greater than 110 ohms

Replace the cooling fan relay.

  • If between 70-110 ohms
  1. Test for infinite resistance between following terminals:
  • 30/3 and 86/1
  • 30/3 and 87/5
  • 30/3 and 85/2
  • 85/2 and 87/5
  • If less than infinite resistance

Replace the cooling fan relay.

  • If infinite resistance
  1. Install a 20 A fused jumper wire between relay terminal 85/2 and 12 V.
  2. Install a jumper wire between relay terminal 86/1 and ground.
  3. Test for less than 2 ohms between terminals 30/3 and 87/5.
  • If 2 ohms or greater

Replace the cooling fan relay.

  • If less than 2 ohms
  1. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  • Relay Replacement (Within an Electrical Center) , Relay Replacement (Attached to Wire Harness)
  • Engine Coolant Fan Replacement (LUJ, LUV), Engine Coolant Fan Replacement (2H0)

ENGINE OVERHEATING

Engine Overheating

Engine Overheating

Loss of Coolant

Loss of Coolant

Thermostat Diagnosis

Thermostat Diagnosis

Thermostat Diagnosis

Thermostat Diagnosis

Engine Fails To Reach Normal Operating Temperature

Engine Fails To Reach Normal Operating Temperature

COOLING SYSTEM LEAK TESTING

Special Tools

  • EN 471 Adapter
  • EN 6327 A Cooling System Test Adapter

For equivalent regional Tools, refer to Special Tools.

WARNING: Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap.

Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.

WARNING: In order to help avoid being burned, do not remove the radiator cap while the engine and the radiator are hot. Scalding fluid and steam can be blown out under pressure if the cap is removed too soon.

  1. Remove the surge tank cap.
  2. Check the coolant level.

Fill the coolant level to the COLD mark if necessary.

  1. Pull the coolant expansion tank from the bracket in the direction of the battery.

NOTE: Follow manufacturer instructions

  1. Attach the coolant system tester with EN 471 adapter and EN 6327 A adapter to the coolant expansion tank.
  2. Apply approximately 100 kPa (15 psi) to the cooling system.
  3. Check the cooling system for leaks.
  4. Remove the cooling system tester.
  • Release the pressure
  • Remove the cooling system tester with EN 471 adapter
  1. Install the surge tank cap.

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