Engine Cooling System: Diagnosis Chevrolet Traverse I

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(ref-365273-S03182733772010070600000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-365273-S36821411302010070600000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-365273-S42262158172010070600000) provides an overview of each diagnostic category.

Diagnostic Fault Information

Typical Scan Tool Data

Cooling Fan Relays

Conditions for Running the DTC

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

Conditions for Clearing the MIL/DTC

DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs.

Diagnostic Aids

1. 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.
2. 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.

Circuit/System Testing

1. Ignition OFF, disconnect all three cooling fan relays.
2. Ignition ON, verify that a test lamp illuminates between ground and the relay coil ignition circuit terminal listed below: Fan 1 relay and Fan 3 relay terminal 85 Series/parallel fan 2 relay terminal 86 If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay coil ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.
3. Test for 2.6-4.6 V between ground and the relay coil control circuit terminal listed below: Fan 1 relay and Fan 3 relay terminal 86 Series/parallel fan 2 relay terminal 85 If less than the specified range, test the relay coil control circuit for an open/high resistance or for a short to ground. If the circuit tests normal, replace the ECM. If greater than the specified range, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Connect a test lamp between the relay coil control circuit terminal and the relay coil ignition circuit terminal.
5. Command the fan 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 OFF, replace the ECM.
6. If all circuits test normal, test or replace the relay.

Component Testing

1. Ignition OFF, disconnect the cooling fan relay.
2. Test for 70-110 ohms between terminals 85 and 86. If not within the specified range, replace the relay.
3. Measure the resistance between the terminals listed below. The DMM should display O.L. 30 and 86 30 and 87 30 and 85 85 and 87 If less than the specified range, replace the relay.
4. Test for less than 2 ohms between terminals 30 and 87A. If greater than the specified range, replace the relay.
5. Install a 20 A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

1. Perform the «Diagnostic System Check - Vehicle»(ref-365273-S03182733772010070600000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-365273-S36821411302010070600000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-365273-S42262158172010070600000) provides an overview of the diagnostic category.

1. The engine is running for greater than 30 seconds.
2. DTC P0116, P0117, P0118, or P0128 are not set.

Conditions for Setting the DTC

The ECM detects that engine coolant temperature is greater than 136°C (277°F) for more than 1 second or a cumulative time of 10 seconds.

Action Taken When the DTC Sets

1. DTC P1258 is a Type A DTC.
2. The engine will operate in the Overheated Engine Protection Operating Mode.
3. The instrument panel (IP) will illuminate the coolant indicator lamp and the driver information center (DIC), if equipped, may display a message.

Conditions for Clearing the DTC

DTC P1258 is a Type A DTC.

Important Preliminary Inspections Before Starting

Before using the Symptom diagnosis, perform the following

1. Perform «Diagnostic System Check - Vehicle»(ref-365273-S03182733772010070600000) and verify all of the following items: Ensure that the engine control module (ECM) and indicator lamp are operating correctly. Ensure that there are no diagnostic trouble codes (DTCs) that are stored. Scan tool data is within a normal operating range.
2. Verify the customer concern.
3. 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.
4. Locate the correct symptom. Perform the tests and inspections associated with the symptom.

Review the system operation in order to familiarize yourself with the system functions. Refer to Cooling Fan Description and Operation .

Visual/Physical Inspection

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 areas

1. Ensure that the control module grounds are clean, tight, and correctly located.
2. Inspect cooling system hoses and pipes for splits, kinks, and proper connections. Inspect thoroughly for any type of a leak or a restriction.
3. Inspect for a dirty or restricted radiator and HVAC condenser.
4. Inspect for aftermarket devices which could affect the operation of the Cooling System.
5. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
6. 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»(ref-365258-S01459429742010070600000)
2. «Cooling Fan Inoperative»(ref-365258-S04104162322010070600000)
3. «Engine Overheating»(ref-365258-S30050533442010070600000)
4. «Loss of Coolant»(ref-365258-S23675562572010070600000)
5. «Thermostat Diagnosis»(ref-365258-S03263771262010070600000)
6. «Engine Fails To Reach Normal Operating Temperature»(ref-365258-S24123967092010070600000)

1. Perform the «Diagnostic System Check - Vehicle»(ref-365273-S03182733772010070600000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-365273-S36821411302010070600000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-365273-S42262158172010070600000) provides an overview of each diagnostic category.

1. Ignition OFF, disconnect the high speed relay, which is FAN 3 relay 43.
2. Ignition ON, observe that both fans are now OFF. If both fans are OFF, replace the high speed relay. If either fan is still activated, remove the low speed relay, which is FAN 1 relay 42. If both fans are now OFF, replace the low speed relay. If either fan is still activated, test for a short to voltage in the fan voltage supply circuit.

1. Perform the «Diagnostic System Check - Vehicle»(ref-365273-S03182733772010070600000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-365273-S36821411302010070600000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-365273-S42262158172010070600000) provides an overview of each diagnostic category.

1. 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.
2. 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.

1. Ignition OFF, disconnect the cooling fan relays.
2. Connect a 30 A fused jumper between the relay switch circuit terminal 30 and the relay ground circuit terminal 87 at the series/parallel fan 2 relay connector. This will complete the left side fan ground circuit. Leave this jumper in place for the remainder of this procedure.
3. Ignition ON, verify that a test lamp illuminates between the relay switch B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the appropriate relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay switch B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the relay.
4. Connect a 30 A fused jumper between the relay switch B+ circuit terminal 30 and the relay controlled output circuit terminal 87. Verify the appropriate fan is activated If the appropriate fan does not activate, test the relay controlled output 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 circuit tests normal, replace the fan.
5. Install the series/parallel fan 2 relay. Verify both fans activate at low speed. If both fans do not activate, test the relay controlled output circuit terminal 87A of the series/parallel fan 2 relay for a short to ground or an open/high resistance.
6. If all circuits test normal, test or replace the relay.

1. Ignition OFF, disconnect the cooling fan relay.
2. Test for 70-110 ohms between terminals 85 and 86. If not within the specified range, replace the relay.
3. Measure the resistance between the terminals listed below. The DMM should display O.L. 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified range, replace the relay.
4. Test for less than 2 ohms of resistance between terminals 30 and 87A. If greater than the specified range, replace the relay.
5. Install a 20 A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

Diagnosis Procedure

1. Use a tempilstick in order to find the opening and the closing temperatures of the thermostat. J 24731 188 tempilstick melts at 87°C (188°F). The thermostat should begin to open at 90°C (194°F). J 24731 206 tempilstick melts at 97°C (206°F). The thermostat should be fully open at 107°C (225°F).
2. Replace the thermostat if it does not operate properly between this temperature range.

1. Perform the «Diagnostic System Check - Vehicle»(ref-365273-S03182733772010070600000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-365273-S36821411302010070600000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-365273-S42262158172010070600000) provides an overview of each diagnostic category.

Note. The 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

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-365258-S22652464802010070600000) .
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-365258-S22652464802010070600000) . 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 Procedure

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(ref-365258-S21197656732010070600000) .
3. Use the J-24460-01: tester in order to apply pressure to the cooling system. Do not exceed the pressure cap rating.
4. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gage for any pressure loss.
5. Repair any leaks as required.