Inspection and Verification

Climate Control System

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





a A leak in the vacuum control circuit may occur during acceleration (slow leak), may exist at all times (large leak) and may exist only when specific functions are selected (indicating a leak in that portion of the circuit). The vacuum hoses used in the passenger compartment control circuit are constructed from PVC plastic material. The vacuum hoses used in the engine compartment are constructed of Hytrel(R). Because of the materials used, never pinch the vacuum hoses off during diagnosis to locate a leak. A wood golf tee can be used as a plug when it is necessary to plug one end of the vacuum hose for leak test purposes.

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 Module Communications Network Testing and Inspection, No Power To The Scan Tool, to diagnose no power to 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 Module Communications Network Testing and Inspection to diagnose no response from the PCM.

7. Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to Module Communications Network Testing and Inspection.

- If the network test passes, retrieve and record Continuous Memory Diagnostic Trouble Codes (CMDTCs).

8. Clear the continuous DTCs and carry out the self-test diagnostics for the PCM.

9. NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the PCM DTC Chart. PCM DTC Chart

If the HVAC DTCs retrieved are related to the concern, go to the HVAC Module DTC Chart DTC Chart. If the PCM DTCs retrieved are related to the concern, go to the PCM DTC Chart PCM DTC Chart. For all other DTCs, refer to Multifunction Electronic Modules Testing and Inspection.

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