Inspection and Verification

INSPECTION AND VERIFICATION

1. Verify the customer concern by operating the climate control system to duplicate the condition.
2. Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection Chart:

3. As pinpoint tests and measurements are being carried out, be sure to inspect for any disconnected, loose-fitting or incorrectly installed component, module and in-line electrical connectors and pins.
4. If the inspection reveals obvious concerns that can be readily identified, repair as necessary.

5. 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).

6. 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.

7. 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) to diagnose no response from the PCM or HVAC module - electronic automatic temperature control (EATC).

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

9. Carry out the self-test diagnostics from the PCM or HVAC module - EATC.

10. 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 any of the EATC DTCs retrieved are related to the concern, go to the HVAC Module - Electronic Automatic Temperature Control (EATC) 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). Diagnostic Trouble Code Tests and Associated Procedures

11. If no DTCs related to the concern are retrieved. GO to Symptom Chart - Climate Control Systems. Symptom Chart - Climate Control Systems