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Engine Cooling System: Diagnosis Chevrolet HHR I

Cooling System (Mechanical) ~1688 words

DIAGNOSTIC CODE INDEX

DTCDescription
DTC P0480 (2.2L and 2.4L)P0480: Cooling Fan Relay Control Circuit
DTC P0480, P0691, or P0692 (2.0)P0480: Cooling Fan Speed Output Circuit P0691: Cooling Fan Speed Output Circuit Low Voltage P0692: Cooling Fan Speed Output Circuit High Voltage

DIAGNOSTIC CODE INDEX

Diagnostic Starting Point - Engine Cooling

Begin the system diagnosis with the diagnostic system check. Refer to Diagnostic System Check - Vehicle . The Diagnostic System Check - Vehicle will provide the following information

  1. The identification of the control modules which command the system
  2. The ability of the control modules to communicate through the serial data circuits
  3. The identification of any stored DTCs and their status

The use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(ref-299594-S04632865592008092400000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299594-S36605711112008092400000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299594-S36190634062008092400000) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Cooling Fan Relay Control CircuitP0480P0480P0480
Cooling Fan Relay Coil Voltage Supply CircuitP0480P0480

Conditions for Running the DTC

  1. The ignition is ON.
  2. The system voltage is between 9-18 volts.
  3. The relay control circuit is transitioned from OFF to ON, or ON to OFF.

Conditions for Setting the DTC

  1. An improper voltage level has been detected on the cooling fan relay control circuit.
  2. The condition must be present for a minimum of 30 seconds.

Action Taken When the DTC Sets

DTC P0480 is a Type B DTC.

Conditions for Clearing the DTC

DTC P0480 is a Type B DTC.

Circuit/System Testing

  1. Ignition OFF, disconnect the relay.
  2. Ignition ON, connect two test lamps in series between the positive terminal at the battery and the relay control circuit terminal 86 at the relay connector.
  3. Command the relay ON and OFF with a scan tool. A test lamp should turn ON and OFF when changing between the commanded states. If a test lamp is always ON, test the relay control circuit for a short to ground. If the circuit tests normal, replace the ECM. If the test lamps are always OFF, test the relay control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Connect a 30A fused jumper wire between the positive voltage terminal at the battery and the fan voltage supply circuit terminal 87 and verify fan activation. If the fan does not activate, test the fan voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fan.
  5. Ignition ON, connect a 30A fused jumper wire between the relay switch voltage supply circuit terminal 30 and the fan voltage supply circuit terminal 87 and verify fan activation. If the fan does not activate, test the relay switch voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and it's fuse is open, test all connected components and replace as necessary.
  6. Ignition ON, verify that a test lamp illuminates between the relay coil voltage supply circuit terminal 85 and ground. If the test lamp does not illuminate, test the relay coil voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test all connected components and replace as necessary.
  7. If all circuits and the ECM test normal, replace the relay.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299594-S04632865592008092400000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299594-S36605711112008092400000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299594-S36190634062008092400000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Speed Control CircuitP0691P0480P0692P0480
  1. The engine speed is more than 80 RPM.
  2. The system voltage is between 10-18 volts.
IMPORTANTThe Circuit/System Verification must be performed first or misdiagnosis may result.
  1. Ignition OFF, disconnect the cooling fan speed control module.
  2. Ignition OFF, install a test lamp between the cooling fan speed control circuit terminal 4 and B+. The lamp should be OFF. If the lamp is ON, test the cooling fan speed control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  3. Ignition ON, command the cooling fan speed from 10-90 percent with a scan tool. The brightness of the lamp should change with the commanded states. If the lamp brightness does not change correctly, test the cooling fan speed control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. If the ECM and the control circuit test normal, replace the cooling fan assembly.

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the Cooling System. Refer to «Checking Aftermarket Accessories»(ref-299596-S12390038412008092400000) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
  3. Inspect the surge tank reservoir for the proper coolant level.

Symptom List

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

  1. «Cooling Fan Always On (2.4L)»(ref-299633-S00963143262008092400000) or «Cooling Fan Always On (2.0)»(ref-299633-S31516468972008092400000)
  2. «Cooling Fan Inoperative (2.4L)»(ref-299633-S10190314432008092400000) or «Cooling Fan Inoperative (2.0)»(ref-299633-S30138342312008092400000)
  3. «Engine Overheating»(ref-299633-S39565651722008092400000)
  4. «Loss of Coolant»(ref-299633-S37390994882008092400000)
  5. «Thermostat Diagnosis»(ref-299633-S42129844462008092400000)
  6. «Coolant Heater Inoperative»(ref-299633-S21516639142008092400000)
  7. «Engine Fails To Reach Normal Operating Temperature»(ref-299633-S20742213632008092400000)
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299594-S04632865592008092400000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299594-S36605711112008092400000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299594-S36190634062008092400000) provides an overview of each diagnostic category.
IMPORTANTYou must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Ignition OFF, disconnect the relay.
  2. Ignition ON, observe that the fan is not activated. If the fan is not activated, replace the relay. If the fan is activated, test the fan voltage supply circuit for a short to voltage.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299594-S04632865592008092400000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299594-S36605711112008092400000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299594-S36190634062008092400000) provides an overview of each diagnostic category.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299594-S04632865592008092400000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299594-S36605711112008092400000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299594-S36190634062008092400000) provides an overview of each diagnostic category.
IMPORTANTYou must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Ignition OFF, disconnect the relay.
  2. Connect a 30A fused jumper between the positive terminal at the battery and the fan voltage supply circuit terminal 82 at the relay connection and verify fan activation. If the fan does not activate, test the fan voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, test the fan ground circuit for an open/high resistance. If the fan did not activate and the circuits test normal, replace the fan.
  3. Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal 30 and the fan voltage supply circuit terminal 87 at the relay connection and verify fan activation. If the fan does not activate, test the relay switch voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test all connected components and replace as necessary.
  4. If the fan and all circuits test normal, replace the relay.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299594-S04632865592008092400000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299594-S36605711112008092400000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299594-S36190634062008092400000) provides an overview of each diagnostic category.
IMPORTANTThe Circuit/System Verification must be performed first or misdiagnosis may result.
  1. Ignition OFF, disconnect the cooling fan speed control module.
  2. Ignition OFF, measure between ground and the cooling fan speed control module ground circuit terminal 2 at the engine harness connector for less than 1 ohm of resistance. If more than 1 ohm, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the cooling fan control module voltage supply circuit terminal 1 and ground. The lamp should illuminate. If the lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, replace the cooling fan assembly.
  4. If all circuits test normal, replace the cooling fan assembly.

Thermostat Test Procedure Using Glycol

Inspect the operation of the thermostat by hanging the thermostat on a hook in a 33 percent glycol solution.

In order to inspect if the thermostat valve is opening properly, perform the following test

  1. Completely submerge the thermostat in a glycol solution. The solution should be 11°C (22°F) above the temperature indicated on the thermostat valve.
  2. Thoroughly agitate the solution. Under these conditions, the thermostat valve should open.

In order to inspect if the thermostat valve is closing properly, perform the following test

  1. Completely submerge the thermostat in a glycol solution. The solution should be 6°C (10°F) below the temperature indicated on the thermostat valve.
  2. Thoroughly agitate the solution. Under these conditions, the thermostat valve should close completely.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299594-S04632865592008092400000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299594-S36605711112008092400000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299594-S36190634062008092400000) provides an overview of each diagnostic category.
IMPORTANTThe power supply cord will read open due to an internal thermal switch if the ambient temperature is above -18°C (0°F).
  1. Test the engine coolant heater for an open or short to ground. If open or shorted, replace the heater.
  2. If the heater tests normal, replace the coolant heater power cord.

Pressure Cap Testing

Special Tools

  1. J 24460-01 Cooling System Pressure Tester. See «Special Tools»(ref-299633-S02913904972008092400000) .
  2. J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(ref-299633-S02913904972008092400000) .
  1. Remove the pressure cap.
  2. Wash the pressure cap sealing surface with water.
  3. Use J 24460-01 (1) with J 42401 (2) in order to test the radiator cap. See «Special Tools»(ref-299633-S02913904972008092400000) .
  4. Test the pressure cap for the following conditions: Pressure the release when J 24460-01 exceeds the pressure rating of the pressure cap. See «Special Tools»(ref-299633-S02913904972008092400000) . Maintain the rated pressure for at least 10 seconds. Note the rate of pressure loss.
  5. Replace the pressure cap under the following conditions: The pressure cap does not release the pressure which exceeds the rated pressure of the cap. The pressure cap does not hold the rated pressure.

Cooling System Leak Testing

Tools Required

  1. J 24460-01 Cooling System Pressure Tester. See «Special Tools»(ref-299633-S02913904972008092400000) .
  2. J 42401 Radiator Cap/Surge Tank Test Adapter. See «Special Tools»(ref-299633-S02913904972008092400000) .
CAUTIONUnder 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.
CAUTIONIn 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»(ref-299633-S22458925582008092400000) .
  3. Wash the pressure cap mating surface with water.
  4. Use the J 24460-01 with J 42401 in order to apply pressure to the cooling system. See «Special Tools»(ref-299633-S02913904972008092400000) . Do not exceed the pressure cap rating.
  5. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gage for any pressure loss.
  6. Repair any leaks as required.

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