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Engine Cooling System: Diagnosis Saturn VUE II

Cooling System (Mechanical) ~2390 words

DIAGNOSTIC CODE INDEX

DTCDescription
DTC P0480 or P0481 (2.2L and 2.4L)Cooling Fan Relay 1/2 Control Circuit
DTC P0480 or P0481 (3.5L)Cooling Fan Relay 1/2 Control Circuit

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.

Scan Tool Output Controls

Scan Tool Output ControlAdditional Menu Selection(s)Description
Fan Control 1 CommandGeneral Info OutputsThe scan tool displays a commanded state of On or Off. This allows you to communicate with the ECM and activate or deactivate the cooling fan relay, manually turning the fans On and Off.
Fan Control 2 CommandGeneral Info OutputsThe scan tool displays a commanded state of On or Off. This allows you to communicate with the ECM and activate or deactivate the cooling fan relay, manually turning the fans On and Off.

Engine Control Module (ECM) L61 Scan Tool Output Controls

Scan Tool Output ControlAdditional Menu Selection(s)Description
Fan Control 1 CommandGeneral Info OutputsThe scan tool displays a commanded state of On or Off. This allows you to communicate with the PCM and activate or deactivate the cooling fan relay, manually turning the fan On and Off.
Fan Control 2 and 3 CommandGeneral Info OutputsThe scan tool displays a commanded state of On or Off. This allows you to communicate with the PCM and activate or deactivate the cooling fan relays, manually turning the fans On and Off.

Powertrain Control Module (PCM) L66 Scan Tool Output Controls

Scan Tool Data List

Use the Scan Tool Data Display Values and Definitions Information in order to assist in diagnosing the HVAC Control Module problems. Compare the vehicles actual scan tool data with the typical data display value table information. Use the data information in order to aid in understanding the nature of the problem when the vehicle does not match with the typical data display values.

The scan tool data values were taken from a known good vehicle under the following conditions

  1. The ignition switch is in the ON position.
  2. The engine is running at idle.
  3. The vehicle is in PARK.
  4. The doors are closed.
  5. The windows are closed.
  6. The A/C is ON.
  7. The ambient air temperatures are at 22-27°C (70-80°F).
Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-27°C (70-80°F)
Battery 1HVAC DataVoltsBattery Voltage
Low CoolantSwitch InputsYes/NoNo

Body Control Module (BCM)

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-27°C (70-80°F)
Fan Control 1 CommandGeneral Info OutputsOn/OffVaries
Fan Control 2 CommandGeneral Info OutputsOn/OffVaries
ECTInputs/Outputs/Idle Speed ControlC/FC/F

Engine Control Module (ECM) - L61/2.2L

Scan Tool ParameterData ListUnits DisplayedTypical Data Value
Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-27°C (70-80°F)
Fan Control 1 CommandGeneral Info OutputsOn/OffVaries
Fan Control 2 CommandGeneral Info OutputsOn/OffVaries
ECTInputs/Outputs/Idle Speed ControlC/FC/F

Powertrain Control Module (PCM) - L66/3.5L

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(ref-269313-S28792172412007103000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-269313-S33755100492007103000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-269313-S20940808192007103000000) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Low Speed Cooling Fan Relay Control CircuitP0480P0480P0480
Low Speed Cooling Fan Relay Coil Voltage Supply CircuitP0480P0480P0480
High Speed Cooling Fan Relay Control CircuitP0481P0481P0481
High Speed Cooling Fan Relay Coil Voltage Supply CircuitP0481P0481P0481

DTC P0480 or P0481 (2.2L and 2.4L)

Conditions for Running the DTC

  1. The ignition is ON.
  2. The system voltage is between 8-18 volts.
  3. The engine speed is more than 40 RPM.
  4. The ECM driver transitions from ON to OFF or from OFF to ON.

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

  1. DTC P0480 is a Type B DTC.
  2. DTC P0481 is a Type B DTC.

Conditions for Clearing the DTC

  1. DTC P0480 is a Type B DTC.
  2. DTC P0481 is a Type B DTC.

Circuit/System Testing

  1. Ignition OFF, disconnect the affected relay.
  2. Ignition ON, connect a test lamp between the positive terminal at the battery and the relay control circuit terminal.
  3. Command the relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the 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 lamp is 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 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 and the fan voltage supply circuit terminal 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, replace the relay.
  6. Ignition ON, verify that a test lamp illuminates between the relay coil voltage supply circuit terminal 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, replace the relay.
  7. If all circuits and the ECM test normal, replace the affected relay.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-269313-S28792172412007103000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-269313-S33755100492007103000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-269313-S20940808192007103000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Low Speed Cooling Fan Relay Control CircuitP0480P0480P0480
Low Speed Cooling Fan Relay Coil Voltage Supply CircuitP0480P0480P0480
High Speed Cooling Fan Relay Control CircuitP0481P0481P0481
High Speed Cooling Fan Relay Coil Voltage Supply CircuitP0481P0481P0481
Series/Parallel Cooling Fan Relay Control CircuitP0481P0481P0481
Series/Parallel Cooling Fan Relay Coil Voltage Supply CircuitP0481P0481P0481

DTC P0480 or P0481 (3.5L)

  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.
  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.
  1. DTC P0480 is a Type B DTC.
  2. DTC P0481 is a Type B DTC.
  1. DTC P0480 is a Type B DTC.
  2. DTC P0481 is a Type B DTC.
  1. Ignition OFF, disconnect the series/parallel 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. Ignition ON, connect a test lamp between the positive terminal at the battery and the affected relay control circuit terminal.
  5. Command the affected relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the relay control circuit for a short to ground. If the circuit tests normal, replace the PCM. If the test lamp is always OFF, test the relay control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM.
  6. 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.
  7. 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.
  8. 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.
  9. If all circuits and the PCM 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-269314-S03598167672007103000000) .
  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. «Low Engine Coolant Indicator Always On»(ref-269357-S13633280982007103000000)
  2. «Cooling Fan Always On (2.2L and 2.4L)»(ref-269357-S37155452532007103000000) or «Cooling Fan Always On (3.5L)»(ref-269357-S09802372712007103000000)
  3. «Cooling Fan Inoperative (2.2L and 2.4L)»(ref-269357-S15082566402007103000000) or «Cooling Fan Inoperative (3.5L)»(ref-269357-S02767123152007103000000)
  4. «Engine Overheating»(ref-269357-S11347385712007103000000)
  5. «Loss of Coolant»(ref-269357-S33288958712007103000000)
  6. «Thermostat Diagnosis»(ref-269357-S21289534462007103000000)
  7. «Engine Fails To Reach Normal Operating Temperature»(ref-269357-S42040585912007103000000)
  1. Perform the «Diagnostic System Check - Vehicle»(ref-269313-S28792172412007103000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-269313-S33755100492007103000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-269313-S20940808192007103000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition 1Lamp ONLamp ON
Coolant Level Switch SignalLamp ONLamp ONLamp OFF

Low Engine Coolant Indicator Always On

IMPORTANTCircuit/System Verification must be performed before performing the Circuit/System Testing.
  1. Turn ON the ignition, with the engine OFF.
  2. Verify that the low coolant indicator turns ON and OFF with each command when the instrument cluster indicators are commanded ON and OFF with a scan tool. If the low coolant level indicator does NOT turn OFF, test for poor connections at the IPC or a faulty IPC.
  3. Ignition ON, disconnect the coolant level switch.
  4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test the circuit for a short to ground.
  5. Ignition ON, use a 3A fused jumper wire to connect harness terminal A to terminal B. If the low coolant level indicator turns OFF, replace the coolant level switch. If the low coolant level indicator does not turn OFF, test the signal circuit of the coolant switch for an open circuit or high resistance. If the signal circuit test normal, inspect for poor connections at the BCM or a faulty BCM.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-269313-S28792172412007103000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-269313-S33755100492007103000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-269313-S20940808192007103000000) 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 relays.
  2. Ignition ON, observe that the fan is not activated. If the fan is not activated, replace the faulty relay. If the fan is activated, test the fan voltage supply circuits for a short to voltage.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-269313-S28792172412007103000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-269313-S33755100492007103000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-269313-S20940808192007103000000) provides an overview of each diagnostic category.
  1. Ignition OFF, disconnect the 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-269313-S28792172412007103000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-269313-S33755100492007103000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-269313-S20940808192007103000000) provides an overview of each diagnostic category.
  1. Remove the relays.
  2. Install a 30A fused jumper at the positive terminal at the battery.
  3. One at a time, connect the other end of the jumper to each fan voltage supply circuit terminal at each relay connection and verify fan activation. If the appropriate 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 does not activate and the circuits test normal, replace the fan.
  4. 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 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.
  5. Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal at the high speed 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.
  6. If the circuits test normal, test and replace the faulty relay.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-269313-S28792172412007103000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-269313-S33755100492007103000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-269313-S20940808192007103000000) provides an overview of each diagnostic category.
  1. Ignition OFF, disconnect the relays.
  2. Install a 30A fused jumper between the relay switch supply circuit terminal and the normally open relay switch contact circuit terminal at the series/parallel relay connector. Leave this jumper installed for the remainder of this procedure.
  3. Install a 30A fused jumper at the positive terminal at the battery.
  4. One at a time, connect the other end of the jumper to each fan voltage supply circuit terminal at each relay connection and verify fan activation. If the appropriate 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 does not activate and the circuits test normal, replace the fan.
  5. Ignition ON, install a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal at the low speed 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.
  6. Ignition ON, install a 30A fused jumper between the relay switch voltage supply circuit terminal and the fan voltage supply circuit terminal at the high speed 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.
  7. If the circuits test normal, test and replace the faulty relay.

Thermostat Diagnosis

StepActionYesNo
1Pressure check the cooling system and the cap for leaks. Repair any leaks before proceeding with the diagnosis. Four cylinder engines use an 82°C (185°F) thermostat. Six cylinder engines use a 91°C (195°F) thermostat. Ambient temperatures should be between 13-38°C (55-100°F). Place the HVAC controls in the OFF position. Run a cold engine at idle 20-21°C (68-70°F) for 15-20 minutes before checking the engine temperature. Is the repair complete?Go to Step 2
2Verify the engine coolant temperature with a Scan Tool at idle. See Special Tools . Is the engine temperature below 85°C (185°F)?Go to Step 5Go to Step 3
3Verify the engine coolant temperature with a Scan Tool at idle. See Special Tools . Is the engine coolant temperature between 85-96°C (185-205°F)?System OKGo to Step 4
4Verify the engine coolant temperature with a Scan Tool at idle. See Special Tools . Is the engine coolant temperature over 96°C (205°F)?Go to Step 7
5Test the thermostat for the following conditions: Opening early Seal is leaking Are either of these conditions present?Go to Step 6System OK
6Replace the thermostat. Refer to Thermostat Replacement (2.2L (L61)) or Thermostat Replacement (2.4L (LAT)) or Thermostat Replacement (3.5L (L66)) . Is the repair complete?System OK
7Is the radiator inlet hot?Go to Step 8Go to Step 14
8Turn ON the heater. Check for hot air at the heater outlets. Is the air hot?Go to Step 9Go to Step 12
9Inspect for blockage in the radiator. Did you find any blockage?Go to Step 10Go to Step 11
10Repair the blockage. Reinspect the radiator with the Scan Tool . See Special Tools . Is the repair complete?System OK
11Replace thermostat. Refer to Thermostat Replacement (2.2L (L61)) or Thermostat Replacement (2.4L (LAT)) or Thermostat Replacement (3.5L (L66)) . Reinspect the radiator with the Scan Tool . See Special Tools . Is the repair complete?System OK
12Rev the engine several times to remove any air. Inspect for blockage in the heater circuit. Inspect for pinched or buckled hoses. Did you find any blockage?Go to Step 13Go to Heating Performance Diagnostic
13Repair the blockage. Reinspect the radiator with the Scan Tool . See Special Tools . Is the repair complete?System OK
14Air may be in the system. Add coolant to surge tank if low. Reinspect the radiator inlet hose. Is the hose hot?Go to Step 8Go to Step 15
15Inspect for blockage in the following locations: The cylinder head The radiator The radiator hoses The radiator nipples Did you find any blockage?Go to Step 16Go to Step 17
16Repair the blockage. Reinspect the radiator with the Scan Tool . See Special Tools . Is the repair complete?System OK
17Repair the thermostat. Reinspect the radiator with the Scan Tool . See Special Tools . Is the repair complete?System OK

Thermostat Diagnosis

Cooling System Leak Testing

Tools Required

  1. SA9141E Cooling System Pressure Test Kit. See «Special Tools»(ref-269357-S31048431392007103000000) .
  2. J 42401 Radiator Cap / Surge Tank Test Adapter. See «Special Tools»(ref-269357-S31048431392007103000000) .
  1. Remove the pressure cap.
  2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(ref-269357-S40713185172007103000000) .
  3. Wash the pressure cap mating surface with water.
  4. Use the SA9141E with J 42401 in order to apply pressure to the cooling system. See «Special Tools»(ref-269357-S31048431392007103000000) . Wet the O-rings on the Surge Tank Pressure Test Adapter J42401-2 (insert) with water or clean coolant and insert into tank. Wet the rubber gasket of the cap adapter J42401-3 (cap) and install on surge tank.
  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.

More articles — Engine Cooling System