Inspection and Verification

INSPECTION AND VERIFICATION

1. Verify the customer's concern by operating the climate control system to duplicate the condition.
2. Inspect to determine if one of the following mechanical or electrical concerns apply:

Visual Inspection Chart:

3. If the inspection reveals obvious concerns that can be readily identified, repair as necessary.

4. NOTE: Make sure to use the latest scan tool software release.

If the cause is not visually evident, connect the scan tool to the data link connector (DLC).

5. NOTE: The vehicle communication module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM.

If the scan tool does not communicate with the VCM:
- check the VCM connection to the vehicle.
- check the scan tool connection to the VCM.
- refer to Information Bus (Module Communications Network), No Power To The Scan Tool, to diagnose no communication with the scan tool.

6. If the scan tool does not communicate with the vehicle:
- verify the ignition key is in the ON position.
- verify the scan tool operation with a known good vehicle.
- refer to information Bus (Module Communications network)

7. Carry out the network test.
- If the scan tool responds with no communications from one or more modules, refer to Information Bus (Module Communications Network)
- If the network test passes, retrieve and record the continuous memory DTCs.

8. Clear the continuous DTCs and carry out the self-test diagnostics from the PCM, HVAC module - EATC or HVAC module - EMTC.

9. NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. REFER to Computers and Control Systems.

If the EMTC or EATC DTCs retrieved are related to the concern, go to the HVAC Module DTC Chart. If the PCM DTCs retrieved are related to the concern, go to Computers and Control Systems. For all other DTCs, refer to Body Control Systems (Multifunction Electronic Control Module). HVAC Module DTC Chart

10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures