Diagnostic Test

1. Check for any applicable Service Bulletins or Flash updates related to the DTC.

   Are there any applicable Service Bulletins or Flash updates?

   Yes 

   • Perform the applicable repair.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

   No 

   • Go To  2

1. Turn the ignition off.
2. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -64°C (-83°F) until the engine coolant temperature is equal to ambient temperature.
3. Turn the ignition on.
4. With the scan tool, compare the AAT, ECT and IAT sensor values.

   Is the Engine Coolant Temperature Sensor value within 15°C (27°F) of the other two sensor values?

   Yes 

   • Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .

   No 

   • Go To  3

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 appropriate SYSTEM 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.

1. If it is necessary to probe a terminal at a PCM harness connector, connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
   NOTE:

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

   Is the resistance below 3.0 Ohms?

   Yes 

   • Go To  4

   No 

   • Repair the circuit for an open or high resistance.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

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 appropriate SYSTEM 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.

1. If it is necessary to probe a terminal at a PCM harness connector, connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
   NOTE:

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

   Is the resistance below 3.0 Ohms?

   Yes 

   • Go To  5

   No 

   • Repair the circuit for an open or high resistance.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

1. The Electronic Control Unit (ECU) harness connectors must be connected to the ECU during this test step.
2. With the ignition in the off position, disconnect the sensor harness connector.
3. Turn the ignition on.
4. With the scan tool, read DTCs.

Does the scan tool display the SENSOR SIGNAL CIRCUIT HIGH DTC with the connector disconnected?

Yes 

• Replace the faulty sensor in accordance with the Service Information. Refer to SENSOR, AIR TEMPERATURE, INLET, REMOVAL .
• Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

No 

• Go To  6

1. Perform any Service Bulletins that apply.
2. Disconnect all PCM harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
   • Proper connector installation.
   • Damaged connector locks.
   • Corrosion.
   • Other signs of water intrusion.
   • Weather seal damage (if equipped).
   • Bent terminals.
   • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
   • Terminals that have been pushed back into the connector cavity.
   • Check for spread terminals and verify proper terminal tension.

   Repair any conditions that are found.

6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
11. With the scan tool, read DTCs.

    Did the DTC return?

    Yes 

    • Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL .
    • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

    No 

    • The wiring or poor connection problem has been repaired.
    • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .