Inspection and Verification

Communications Network

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of electrical damage.

Visual Inspection Chart:

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

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 DLC.

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.
- Go To Pinpoint Test Q, to diagnose no power to the scan tool. Pinpoint Test Q: No Power To The Scan Tool

5. NOTE: During the network test, the scan tool will first attempt to communicate with the PCM, after establishing communication with the PCM, the scan tool will then attempt to communicate with all other modules on the vehicle.

Carry out the network test.

- If the network test passes, retrieve and record the continuous memory DTCs and proceed to Step 6.

- If the network test fails, GO to Symptom Chart to identify the module not communicating. Symptom Related Diagnostic Procedures

6. If the DTCs retrieved are related to the concern, go to DTC Charts Communications Network. For all other DTCs, refer to the Diagnostic Trouble Code (DTC) Chart in Body Control Systems. Diagnostic Trouble Code (DTC) Chart

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