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Diagnostic Test

  1. CHECK THE ENGINE COOLANT LEVEL 
    WARNING:

    Do not remove or loosen the radiator cap with the system hot and under pressure. Serious burns from coolant can occur.

    1. Check the level of the engine coolant.

      Is the cooling system low on coolant?

      Yes 

      • Fill the coolant to the proper level. Pressure test and inspect the entire cooling system for signs of coolant leaks.

      No 

      • Go To  2
  2. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECU's) and record on the repair order.
    2. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  3

      No 

  3. CHECK FOR ENGINE OVERHEATING PROBLEMS 
    1. Start the engine and allow it to reach operating temperature.
    2. Drive the engine under a various load conditions.
    3. Monitor the engine for an overheating condition.

      Is the engine overheating?

      Yes 

      • Repair the overheating condition in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. ISOLATE AND CHECK THE EGR TEMPERATURE SENSOR (K932) TEMP SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. The ignition must be off when checking the continuity of a circuit.
    2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
    5. Connect the other lead to the circuit being tested at the GPEC Adaptor and measure the resistance of the circuit.
    6. If it is necessary to probe a terminal at a PCM harness connector, connect the special tool # 10436, (GPEC Diagnostic Adapter) to the appropriate PCM harness connector.
      NOTE:

      The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.

      CAUTION:

      Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  5

      No 

  5. ISOLATE AND CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. The ignition must be off when checking the continuity of a circuit.
    2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
    5. Connect the other lead to the circuit being tested at the GPEC Adaptor and measure the resistance of the circuit.
    6. If it is necessary to probe a terminal at a PCM harness connector, connect the special tool # 10436, (GPEC Diagnostic Adapter) to the appropriate PCM harness connector.
      NOTE:

      The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.

      CAUTION:

      Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  6

      No 

  6. CHECK THE EGR COOLER AND HOSES FOR LEAKS 
    1. Pressure test the cooling system and inspect the EGR Cooler Assembly and hoses for signs of a coolant leak.

      Were any leaks found?

      Yes 

      • Repair the leak by repairing or replacing the leaking hoses or EGR Cooler Assembly in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  7
  7. CHECK THE EGR COOLER FOR AN INTERNAL LEAK 
    1. Inspect the inside of the exhaust tailpipe for the presence of engine coolant.
      NOTE:

      A severe leak may also be identified by excessive white smoke from the tailpipe with the engine running resembling the signs of a faulty cylinder head gasket. Before condemning a cylinder head gasket, make sure to inspect for coolant inside the EGR Tube.

    2. If no coolant was found in the tailpipe, disconnect the EGR Tube that connects between the EGR Valve and the Intake Manifold and inspect the inside of the EGR Tube for the presence of engine coolant.

      Was coolant found inside the exhaust tailpipe or EGR Tube?

      Yes 

      No 

      • Go To  8
  8. REPLACE THE EGR TEMPERATURE SENSOR AND RETEST FOR DTCS 
    1. Turn the ignition off.
    2. Replace the EGR Temperature Sensor in accordance with the Service Information. Refer to SENSOR, EGR TEMPERATURE, REMOVAL AND INSTALLATION .
    3. Connect the component and Electronic Control Unit (ECU) harness connectors.
    4. Turn the ignition on.
    5. With the scan tool, erase all DTCs.
    6. Turn the ignition off for a minimum of 10.0 seconds.
    7. Turn the ignition on.
    8. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
    9. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • Replacing the EGR Temperature Sensor repaired the fault.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .
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