Engine Cooling: Diagnosis Hummer H2 I рестайлинг

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.

Diagnostic Fault Information

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 transitioning 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

DTCs P0480 and P0481 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0480 and P0481 are Type B DTCs.

Circuit/System Testing

1. Ignition OFF, disconnect the series/parallel relay, which is the FAN CNTRL relay.
2. Connect a 30A fused jumper between the normally-open switch contact terminals at the series/parallel relay connector in order to complete the fan ground circuit. Leave this jumper in place for the remainder of this procedure.
3. Ignition OFF, disconnect the affected relay.
4. Verify that a test lamp does not illuminate between B+ and the affected relay control circuit terminal.
5. Remove the test lamp.
6. Command the affected relay ON with a scan tool. Verify the scan tool Relay Control Ckt. Short Volts Test Status Parameter is OK. If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
7. Install a 3A fused jumper wire between the control circuit terminal and B+. Command the affected relay ON with a scan tool. Verify the scan tool Relay Control Ckt Short Volts Test Status Parameter is Fault. If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
8. Remove the 3A fused jumper wire.
9. Connect a 30A fused jumper between the positive voltage terminal at the battery and the fan voltage supply circuit terminal at the affected relay connector 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.
10. Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal at the affected relay connector and verify fan activation. If the fan does not activate, test the affected 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.
11. Ignition ON, verify that a test lamp illuminates between the affected relay coil voltage supply circuit terminal and ground. If the test lamp does not illuminate, test the affected 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.
12. If all circuits and the ECM test normal, replace the affected relay.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Cooling System. Refer to «Checking Aftermarket Accessories»(ref-266359-S20868675002007100200000) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Symptom List

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

1. «Cooling Fan Always On»(ref-299178-S01561073372008092200000)
2. «Cooling Fan Inoperative»(ref-299178-S22706933972008092200000)
3. «Engine Overheating»(ref-299178-S20453739962008092200000)
4. «Loss of Coolant»(ref-299178-S16235990592008092200000)
5. «Thermostat Diagnosis»(ref-299178-S26439006322008092200000)
6. «Engine Fails To Reach Normal Operating Temperature»(ref-299178-S15983635712008092200000)

1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.

1. Ignition OFF, leave the series/parallel relay in place while disconnecting the other relays.
2. Ignition ON, observe that the fans are not activated. If the fans are not activated, replace the faulty relay. If a fan is activated, test the fan voltage supply circuits for a short to voltage.

1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.

1. Ignition OFF, disconnect the series/parallel relay.
2. Ignition ON, activate the cooling fan relay 1 with a scan tool. The fan should be OFF. If the fan is activated, test the left fan ground circuit for a short to ground.
3. Ignition OFF, disconnect the remaining relays.
4. Install a 30A fused jumper between the normally-open switch contact terminals at the series/parallel relay connector in order to complete the fan ground circuit. Leave this jumper in place for the remainder of this procedure.
5. One at a time, connect a 30A fused jumper between the positive terminal at the battery and the fan voltage supply circuit terminal at the low speed fan relay and the high speed fan relay connections and verify fan activation. If the appropriate fan does not activate, test the fan voltage supply circuit for a short to ground or open/high resistance. If the circuit tests normal, test the fan ground circuit for an open/high resistance. If the circuits test normal, replace the fan.
6. Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal at the low speed relay and the series/parallel relay connections 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.
7. If the circuits and fans test normal, replace the relay.

Thermostat Test Procedure Using Tempil Sticks

The coolant thermostat can be tested using a temperature (tempil) stick. The temperature stick is a pencil like device. It has a wax material containing certain chemicals which melt at a given temperature. Temperature sticks can be used to determine a thermostat's operating range, by rubbing 87°C (188°F) and 97°C (206°F) sticks on the thermostat housing.

1. Use a tempil stick in order to find the opening and the closing temperatures of the coolant thermostat. J 24731 -188 tempil stick melts at 87°C (188°F). See «Special Tools»(ref-299178-S33492269542008092200000) . The thermostat should begin to open. J 24731 -206 tempil stick melts at 97°C (206°F). See «Special Tools»(ref-299178-S33492269542008092200000) . The thermostat should be fully open.
2. Replace the coolant thermostat if it does not operate properly between this temperature range.

Thermostat Test Procedure Using Glycol

Inspect the operation of the thermostat by hanging the thermostat on a hook in a 50/50 percent solution of DEX-COOL® and clean drinkable water.

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

1. Completely submerge the thermostat in the 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.

Pressure Cap Testing

Tools required

1. J 24460-01 Cooling System Pressure Tester. See «Special Tools»(ref-299178-S33492269542008092200000) .
2. J 42401 Radiator Cap / Surge Tank Test Adapter. See «Special Tools»(ref-299178-S33492269542008092200000) .

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use the J 24460-01 (1) with J 42401 (2) in order to test the pressure cap. See «Special Tools»(ref-299178-S33492269542008092200000) .
4. Test the pressure cap for the following conditions: Pressure release when the J 24460-01 exceeds the pressure rating of the pressure cap. See «Special Tools»(ref-299178-S33492269542008092200000) . 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 pressure which exceeds the rated pressure of the cap. The pressure cap does not hold the rated pressure.

Testing

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(ref-299178-S35683370992008092200000) .
3. Wash the pressure cap mating surface with water.
4. Use the J 24460-01 with the. See «Special Tools»(ref-299178-S33492269542008092200000) . J 42401 in order to apply pressure to the cooling system. See «Special Tools»(ref-299178-S33492269542008092200000) . 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.