Opel Insignia: Diagnostic Information and Procedures

DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LTG)

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 Speed Control Circuit

DTC P0691

Cooling Fan Speed Output Circuit Low Voltage

DTC P0692

Cooling Fan Speed Output Circuit High Voltage

Diagnostic Fault Information

Circuit/System Description

The engine cooling fan system is composed of one electric cooling fan and a cooling fan control module.

The engine control module (ECM) controls the fan speed by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the cooling fan motor in relation to the pulse width modulated signal, which enables cooling fan operation at variable speeds. The ECM will only operate the cooling fan at certain percentages to prevent undesirable noise and vibration. The cooling fan control module is thermally protected to prevent module damage in the case of a short circuit condition in the cooling fan motor.

Conditions for Running the DTC

• The ignition voltage is greater than 11 volts.
• The DTCs run continuously once the above conditions are 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 5 seconds.

Action Taken When the DTC Sets

DTCs P0480, P0691, and P0692 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0480, P0691, and P0692 are Type B DTCs.

Diagnostic Aids

• A delay or ramp up of approximately 12 seconds may occur before the cooling fan activates or changes speed when being commanded with a scan tool.
• In order to set certain DTCs the PCM must command the Cooling Fan system On. Using the scan tool to operate the Cooling Fan will not set certain DTCs. In these cases run the vehicle until it reaches an appropriate condition for the PCM to command the Cooling Fans On.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Cooling Fan 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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

NOTE: A slight delay may occur before the cooling fan activates.

2. Verify the G10 Cooling Fan Motor activates in each available speed when commanding the cooling fan ON with a scan tool. The cooling fan speed should increase with each command.

• The cooling fan does not activate or increase in speed as commanded

Refer to Circuit/System Testing

• Go to next step: The cooling fan activates and increases in speed as commanded

3. 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.

4. Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing

• Go to next step: If the DTC does not set

5. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the G10 Cooling Fan Motor.

2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.

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

1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 2 Ω in the B+ circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, 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 B+ circuit and ground.
   • If less than infinite resistance, repair the short to ground in the circuit.
   • If infinite resistance, replace the G10 Cooling Fan Motor.

• Go to next step: If the test lamp illuminates

NOTE: The cooling fan speed output circuit is pulled-up to a voltage within the ECM, 2-3 volts on the output circuit is normal.

3. Connect a DMM, set on the diode setting, between the G10 Cooling Fan Motor control circuit terminal 4 and ground.

4. Verify the DMM reading is greater than 2.5 V or displays O.L. with the cooling fan commanded OFF.

• 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.
2. Disconnect the harness connector X1 at the K20 Engine Control Module.
3. Test for infinite resistance between the G10 Cooling Fan Motor control circuit terminal 4 and ground.
   • If less than infinite resistance, repair the short to ground in the circuit.
   • If infinite resistance, replace the K20 Engine Control Module.

• Go to next step: If greater than 2.5 V or displays O.L.

5. Command the cooling fan ON to 90% with a scan tool.

6. Verify the DMM reading is less than 1 V.

• If 1 V or greater

1. Ignition OFF.
2. Disconnect the harness connector X1 at the K20 Engine Control Module, ignition ON.
3. Test for less than 1 V between the G10 Cooling Fan Motor control circuit terminal 4 and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • Go to next step: If less than 1 V.
4. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
5. Test for less than 2 Ω in the circuit end to end.
   • If 2 Ω or greater, repair the open in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If less than 1 V

7. Replace the K20 Cooling Fan Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan Replacement (3.6L LGX) for G10 Cooling Fan Motor.
• Control Module References for ECM replacement, setup, and programming

DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LGX)

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 Speed Output Circuit

DTC P0691

Cooling Fan Speed Output Circuit Low Voltage

DTC P0692

Cooling Fan Speed Output Circuit High Voltage

Diagnostic Fault Information

1. Opens left cooling fan fuse without a DTC.
2. Left fan inoperative without a DTC.
3. Opens right cooling fan fuse without a DTC.
4. Right cooling fan inoperative without a DTC.

Circuit/System Description

The engine control module (ECM) commands the speed of the cooling fans based on cooling requirements.

The ECM controls the cooling fan speed by commanding the cooling fan control modules. Each cooling fan control module is supplied power through its own fused power circuit. Each cooling fan control module is supplied ground though its own ground circuit. The ECM sends a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module interprets the signal and operates the cooling fans at the commanded speeds.

Conditions for Running the DTC

• The ignition voltage is 11 volts or greater.
• The engine speed is 400 RPM or greater.
• The ECM driver transitions from ON to OFF or from OFF to ON.
• DTCs P0480, P0691, and P0692 run continuously once the above conditions are 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 5 seconds.

Action Taken When the DTC Sets

• DTCs P0480, P0691, and P0692 are Type B DTCs.

Conditions for Clearing the MIL/DTC

• DTCs P0480, P0691, and P0692 are Type B DTCs.

Diagnostic Aids

• A delay or ramp up of approximately 12 seconds may occur before the cooling fan activates or changes speed when being commanded with a scan tool.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Cooling Fan 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

Scan Tool Reference

K20 Engine Control Module: Scan Tool Information for scan tool information

Circuit/System Verification

NOTE: There is a slight delay before the cooling fans activate.

1. Engine operating, command the Cooling Fans from 0 % to 90 % with a scan tool.

2. Verify the G10 Cooling Fan Motors activates in each available speed.

• The cooling fan does not activate or increase in speed as commanded

Refer to Circuit/System Testing

• Go to next step: The cooling fan activates and increases in speed as commanded

3. 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.

4. Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing

• Go to next step: If the DTC does not set

5. All OK.

Circuit/System Testing

NOTE: Both cooling fan motors must be disconnected or incorrect diagnosis may result.

1. Ignition OFF, disconnect the following G10 Cooling Fan Motors.

• G10L Cooling Fan Motor Left.
• G10R Cooling Fan Motor Right.

2. Ignition ON, verify that a test lamp illuminates between the following terminals and ground.

• G10L Cooling Fan Motor Left - terminal 1
• G10R Cooling Fan Motor Right - terminal 1
• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF, remove the test lamp and turn all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 2 Ω in the appropriate B+ circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, 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 and turn 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 terminals listed below and ground.
   • G10L Cooling Fan Motor Left - terminal 1
   • G10R Cooling Fan Motor Right - terminal 1
   • If less than infinite resistance, repair the short to ground in the circuit.
   • If infinite resistance, replace the appropriate G10 Cooling Fan Motor.

• Go to next step: If the test lamp illuminates

NOTE: The cooling fan speed output circuit is pulled-up to a voltage within the ECM, 3 - 4 volts on the output circuit is normal.

3. Ignition OFF, disconnect the following G10 Cooling Fan Motors.

• G10L Cooling Fan Motor Left
• G10R Cooling Fan Motor Right

4. Connect a DMM, set on the diode setting, between the following terminals and ground.

• G10L Cooling Fan Motor Left - terminal 4
• G10R Cooling Fan Motor Right - terminal 4

5. Ignition ON, verify the DMM reading is greater than 2.5 V or displays O.L. with the cooling fan commanded OFF.

• If 2.5 V or less

1. Ignition OFF, all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
2. Disconnect the K20 Engine Control Module harness connector X1.
3. Test for infinite resistance between the appropriate G10 Cooling Fan Motor control circuit terminal 4 and ground.
   • If less than infinite resistance, repair the short to ground in the circuit.
   • If infinite resistance, replace the K20 Engine Control Module.

• Go to next step: If greater than 2.5 V or displays O.L.

6. Command the Cooling Fan ON to 90 % with a scan tool.

7. Verify the DMM reading is less than 1 V.

• If 1 V or greater

1. Ignition OFF, disconnect harness connector X1 at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the appropriate G10 Cooling Fan Motor control circuit terminal 4 and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • Go to next step: If less than 1 V.
3. Ignition OFF, and all vehicle systems OFF, it may take up to 2 minutes for all vehicle systems to power down.
4. Test for less than 2 Ω in the G10 Cooling Fan Motor control circuit terminal 4, end to end.
   • If 2 Ω or greater, repair the open/high resistance in the control circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If less than 1 V

8. Test or replace the appropriate G10 Cooling Fan Motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan Replacement (3.6L LGX) for G10 Cooling Fan Motor Replacement.
• Control Module References for ECM replacement, setup, and programming

DTC P1258

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 P1258

Engine Coolant Overtemperature - Protection Mode Active

Circuit/System Description

The engine control module (ECM) uses the engine coolant temperature sensor to monitor the engine for an over-temperature condition. This condition occurs when the coolant temperature is above a calibrated value. The ECM will alternately disable 2 groups of cylinders by turning OFF the fuel injectors. By switching between the 2 groups of cylinders, the ECM is able to reduce the temperature of the coolant.

Conditions for Running the DTC

• The engine is operating for greater than 30 seconds.
• DTC P1258 runs continuously once the conditions above have been met.

Conditions for Setting the DTC

The ECM detects that engine coolant temperature is warmer than 131ºC (268ºF) for greater than 2 seconds.

Action Taken When the DTC Sets

• DTC P1258 is a Type A DTC.
• The engine will operate in the Overheated Engine Protection Operating Mode.
• The IP will illuminate the coolant temperature indicator lamp and the driver information center (DIC), if equipped, may display a message.
• If the protection mode is active and an ECT sensor DTC sets, the protection mode will remain active at the start of the next drive cycle until the ECT sensor DTC runs and passes.

Conditions for Clearing the MIL/DTC

DTC P1258 is a Type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics (LGX)

Connector End View Reference

Component Connector End View Index

Description and Operation

• Cooling Fan Description and Operation
• Instrument Cluster Description and Operation
• Indicator/Warning Message Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

K20 Engine Control Module: Scan Tool Information for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify 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 (LTG) or DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LGX).

• Go to next step: If no DTCs is set

NOTE: A short delay occurs before the ECM changes the cooling fan speed.

3. Verify the cooling fan operates at each available speed as commanded with a scan tool.

• Cooling fan does not operate

Refer to Cooling Fan Inoperative (LGX) or Cooling Fan Inoperative (LTG).

• Go to next step: Cooling fan operates

4. Verify that the engine does not overheat.

• Engine overheats

Refer to Engine Overheating.

• Go to next step: Engine does not overheat

5. Operate the vehicle within the Conditions for Running the DTC.

• If the DTC sets

Refer to Symptoms - Engine Cooling.

• Go to next step: If the DTC does not set

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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. 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 relevant 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 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:

• Engine Overheating
• Loss of Coolant
• Thermostat Diagnosis
• Engine Fails To Reach Normal Operating Temperature

Cooling Fan Always On (Dual Fan)

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 two electric cooling fans and a cooling fan control module.

The engine control module (ECM) controls the fan speeds by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the cooling fan motors in relation to the pulse width modulated signal, which enables cooling fan operations at variable speeds. The ECM will only operate the cooling fans at certain percentages to prevent undesirable noise and vibration. The cooling fan control module is thermally protected to prevent module damage in the case of a short circuit condition in the cooling fan motor.

Diagnostic Aids

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.

The cooling fans will not operate when the scan tool Cooling Fan Motor Command parameter displays less than 4 %. This is a normal condition.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Cooling Fan Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify that DTC P0480, P0691, or P0692, is not set.

• If a DTC is set

Refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LTG) or DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LGX).

• Go to next step: If no DTC is set.

3. Verify the scan tool Cooling Fan Motor Command parameter is less than 4 %.

• If 4 % or greater

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

• Go to next step: If less than 4 %

4. Verify that the G10 Cooling Fan Motors are not operating.

• If the G10 Cooling Fan Motors are operating

Test or replace the appropriate G10 Cooling Fan Motor.

• Go to next step: If the G10 Cooling Fan Motors are not operating

5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan Replacement (3.6L LGX) for G10 Cooling Fan Motor Replacement.
• Control Module References.

Cooling Fan Always On (Single Fan)

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 electric cooling fan and a cooling fan control module.

The engine control module (ECM) controls the fan speed by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the cooling fan motor in relation to the pulse width modulated signal, which enables cooling fan operation at variable speeds. The ECM will only operate the cooling fan at certain percentages to prevent undesirable noise and vibration. The cooling fan control module is thermally protected to prevent module damage in the case of a short circuit condition in the cooling fan motor.

Diagnostic Aids

• Certain resistance conditions with IAT or ECT sensors may cause unwarranted cooling fan activation. If the ECM is commanding the cooling fan 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 relevant Temperature Versus Resistance tables.
• The cooling fan will not operate when the scan tool Cooling Fan Motor Command parameter displays less than 4 %. This is a normal condition.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Cooling Fan Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify that DTC P0480, P0691, or P0692, is not set.

• If a DTC is set

Refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LTG) or DTC P0480, P0481,P0691, P0692, P0693, or P0694 (LGX).

• Go to next step: If no DTC is set.

3. Verify the scan tool Cooling Fan Motor Command parameter is less than 4 %.

• If 4 % or greater

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

• Go to next step: If less than 4 %

4. Verify that the G10 Cooling Fan Motor is not operating.

• If the G10 Cooling Fan Motor is operating

Test or replace the G10 Cooling Fan Motor.

• Go to next step: If the G10 Cooling Fan Motor is not operating

5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan Replacement (3.6L LGX) for G10 Cooling Fan Motor Replacement.
• Control Module References

Cooling Fan Inoperative (LGX)

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 two electric cooling fans and a cooling fan control module.

The engine control module (ECM) controls the fan speeds by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the cooling fan motors in relation to the pulse width modulated signal, which enables cooling fan operations at variable speeds. The ECM will only operate the cooling fans at certain percentages to prevent undesirable noise and vibration. The cooling fan control module is thermally protected to prevent module damage in the case of a short circuit condition in the cooling fan motors.

Diagnostic Aids

• The cooling fans will not operate when the scan tool Cooling Fan Motor Command parameter displays less than 4 %. This is a normal condition.
• A delay or ramp up of approximately 12 seconds may occur before the cooling fans activate or change speeds when being commanded with a scan tool.
• The cooling fan Control Function operates as described below when the ignition is ON, and engine is OFF:
  • Command State 1 operates the cooling fans at approximately 18 %
  • Command State 2 operates the cooling fans at approximately 54 %
  • Command State 3 operates the cooling fans at approximately 67 %
  • Command State 4 operates the cooling fans at approximately 85 %
  • Command State 5 operates the cooling fans at approximately 90 %
• During normal operating conditions the ECM may initially activate the cooling fans at 4 or 5 % and then increase to the percentages indicated above, as needed, to satisfy powertrain cooling requirements. Generally, the ECM will operate the cooling fans at the specified percentages but, may scale the percentages either higher or lower in response to generator demand.
• When operating the cooling fans with a scan tool, the Commanded States 1 - 5 should be exercised in order, from OFF to High or High to OFF. The cooling fan control module may disable the cooling fans if a Commanded State is skipped.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Cooling Fan Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify that DTC P0480, P0691, or P0692, is not set.

• If a DTC is set

Refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LTG) or DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LGX).

• Go to next step: If no DTC is set.

NOTE: A slight delay may occur before the cooling fan activates.

3. Verify the G10 Cooling Fan Motors activate and increases in speed with each command using a scan tool.

• The cooling fans do not activate or increase in speed

Refer to Circuit/System Testing

• Go to next step: The cooling fans activate and increases in speed

4. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector G10L Cooling Fan Motor or G10R Cooling Fan Motor.

2. Verify that a test lamp illuminates between the ground circuit terminal 2 and B+ of the inoperative G10 Cooling Fan Motor.

• If the test lamp does not illuminate

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 less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If the test lamp illuminates

3. Test or replace the inoperative G10 Cooling Fan Motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan Replacement (3.6L LGX) for G10 Cooling Fan Motor replacement.
• Control Module References

Cooling Fan Inoperative (LTG)

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 electric cooling fan and a cooling fan control module.

The engine control module (ECM) controls the fan speed by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the cooling fan motor in relation to the pulse width modulated signal, which enables cooling fan operation at variable speeds. The ECM will only operate the cooling fan at certain percentages to prevent undesirable noise and vibration. The cooling fan control module is thermally protected to prevent module damage in the case of a short circuit condition in the cooling fan motor.

Diagnostic Aids

• The cooling fan will not operate when the scan tool Cooling Fan Motor Command parameter displays less than 4 %. This is a normal condition.
• A delay or ramp up of approximately 12 seconds may occur before the cooling fan activates or changes speed when being commanded with a scan tool.
• The cooling fan Control Function operates as described below when the ignition is ON, and engine is OFF:
  • Command State 1 operates the cooling fan at approximately 18 %
  • Command State 2 operates the cooling fan at approximately 54 %
  • Command State 3 operates the cooling fan at approximately 67 %
  • Command State 4 operates the cooling fan at approximately 85 %
  • Command State 5 operates the cooling fan at approximately 90 %
• During normal operating conditions the ECM may initially activate the cooling fan at 4 or 5 % and then increase to the percentages indicated above, as needed, to satisfy powertrain cooling requirements. Generally, the ECM will operate the cooling fan at the specified percentages but, may scale the percentages either higher or lower in response to generator demand.
• When operating the cooling fan with a scan tool, the Commanded States 1 - 5 should be exercised in order, from OFF to High or High to OFF. The cooling fan control module may disable the cooling fan if a Commanded State is skipped.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Cooling Fan Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify that DTC P0480, P0691, or P0692, is not set.

• If a DTC is set

Refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LTG) or DTC P0480, P0481, P0691, P0692, P0693, or P0694 (LGX).

• Go to next step: If no DTC is set.

NOTE: A slight delay may occur before the cooling fan activates.

3. Verify the G10 Cooling Fan Motor activates and increases in speed with each command using a scan tool.

• The cooling fan does not activate or increase in speed

Refer to Circuit/System Testing

• Go to next step: The cooling fan activates and increases in speed

4. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector G10 Cooling Fan Motor.

2. Verify that a test lamp illuminates between the ground circuit terminal 2 and B+.

• If the test lamp does not illuminate

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 less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If the test lamp illuminates

3. Test or replace the G10 Cooling Fan Motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Engine Coolant Fan Replacement (2.0L LTG) or Engine Coolant Fan Replacement (3.6L LGX) for G10 Cooling Fan Motor replacement.
• Control Module References

ENGINE OVERHEATING

DEFINITION: Either of the following conditions indicate a probable engine overheat condition. The engine temperature gauge is in the red (overheat) zone and/or the engine temperature indicator is ON. Hot engine coolant overflows from the coolant recovery reservoir and/or radiator cap onto the ground while the engine is running.

LOSS OF COOLANT

THERMOSTAT DIAGNOSIS

COOLANT HEATER INOPERATIVE

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 coolant heater is a 300 watt heating element that mounts to the engine block. The coolant heater operates using 120 V AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather. The coolant heater also helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. There is an internal thermal switch in the coolant heater cord that prevents operation above -18ºC (0ºF). A weather shield on the cord is provided to protect the plug when not in use.

Reference Information

Electrical Information Reference

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

Circuit/System Testing

NOTE: The coolant heater cord will read Open due to an internal thermal switch if the ambient temperature is above -18ºC (0ºF).

1. Ignition OFF, disconnect the coolant heater cord from the E19 Coolant Heater.

2. Test for 40 - 55 Ω between the terminals of the E19 Coolant Heater.

• If not within 40 - 55 Ω

Replace the E19 Coolant Heater.

• Go to next step: If within 40 - 55 Ω

3. Test for infinite resistance between each terminal of the E19 Coolant Heater and ground.

• If less than infinite resistance

Replace the E19 Coolant Heater.

• Go to next step: If infinite resistance

4. Test for less than 2 Ω between the engine coolant heater cord plug and the engine coolant heater cord connector for each circuit.

• If greater than 2 Ω

Replace the engine coolant heater cord.

• Go to next step: If less than 2 Ω

Go to next step: All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic repair.

ENGINE FAILS TO REACH NORMAL OPERATING TEMPERATURE

Pressure Cap Testing

Special Tools

GE-42401-A Radiator Cap and Surge Tank Test Adapter

For equivalent regional tools, refer to Special Tools.

WARNING: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

1. Remove the pressure cap.

2. Wash the pressure cap sealing surface with water.

3.

Use a commercial cooling system pressure adapter (1) and moisten the rubber with coolant fluid.

4.

Install the commercial adapter (1) to the GE-42401-1A adapter (2). Use a suitable underlay to be able to use enough force. Inspect the assembly for proper seat then.

5.

NOTE: Lubricate GE-42401-1A adapter and pressure cap O-rings with coolant.

The GE-42401-1A adapter and the pressure cap should have room temperature to operate properly.

Use commercial coolant pressure tester (4) along with the commercial adapter (3) and install to the GE-42401-1A adapter (2).

6. Install the assembly to the pressure cap (1) and apply pressure.

7. Test the pressure cap for the following conditions:

• Pressure release when the pressure tester exceeds the pressure rating of the pressure cap.
• Maintain the rated pressure for at least 10 seconds.

8. Note the rate of pressure loss.

9. Replace the pressure cap under the following conditions:

• The pressure cap does not release pressure which exceeds the rated pressure of the cap.
• The pressure cap does not hold the rated pressure.

COOLING SYSTEM LEAK TESTING (CO2 TESTING)

NOTE: This procedure should be used to localize exhaust gas relevant cooling leakages and cooling fluid in the combustion chambers.

1.

Check the cooling system for proper coolant fluid level. The coolant level in the radiator surge tank should match the MAX level marking (1). Correct the coolant level if necessary.

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.

2. Carefully open the radiator surge tank cap one turn by another and release the pressure.

3.

Install a carbon dioxide tester (1) filled with indicator fluid to the radiator surge tank.

4. To ensure the functionality of the indicator fluid, the following test can be performed: 1. Remove the filled indicator fluid chamber of the carbon dioxide tester 2. Blow some breathing air to chamber and the fluid 3. The blue indicator fluid must change the color to yellow, otherwise replace with new fluid 5. Start the engine and allow it to run for some minutes at idle speed.

NOTE: The engine should have a cooling fluid temperature of 80ºC (176 ºF).

6. Aspirate air from the radiator surge tank to the carbon dioxide tester (1). Thereby take care, that no coolant fluid enters the tester.

NOTE: The blue indicator fluid will react with a minimum concentration of carbon dioxide and changes the color to yellow then.

7. If the indicator fluid in the upper chamber of the tester changes its color to yellow, the occurrence of coolant fluid in the combustion chamber is indicated.

8. Stop the engine.

9. Coolant in the combustion chamber could be caused by the following reasons:

• Damaged cylinder head
• Damaged cylinder head gasket
• Damaged engine block
• Defect in the exhaust gas recirculation system

10. Remove the carbon dioxide tester and install the radiator surge tank cap.

Cooling System Leak Testing (Pressure Test)

Special Tools

GE-42401-A Radiator Cap and Surge Tank 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 pressure cap.

2. Test the operation of the pressure cap. Refer to Pressure Cap Testing.

3. Wash the pressure cap mating surface with water.

4.

Install the GE-42401-2 pressure test adapter (1) to the coolant recovery reservoir (2) to plug the reservoir bleeder gallery.

5.

Use a commercial cooling system pressure adapter (1) and moisten the rubber with coolant fluid.

6.

Install the commercial adapter (1) to the GE-42401-3 adapter (2). Use a suitable underlay to be able to use enough force. Inspect the assembly for proper seat then.

7.

Install the assembled adapters (3, 4) to the coolant recovery reservoir (5).

8. Install a commercial cooling system pressure tester (1, 2) to the commercial adapter.

NOTE: Do NOT exceed the pressure cap rating.

9. Using the pressure tester apply pressure to the cooling system.

10. Observe the gage of the pressure tester for any loss.

11. The cooling system should hold the rated pressure for at least 2 minutes.

12. Repair any leaks as required.

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