Initial Inspection and Diagnostic Overview

Inspection and Verification
1. Verify the customer concern.

Visual Inspection Chart:

2. Visually inspect the following for obvious signs of mechanical or electrical damage.
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

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

4. If the cause is not visually evident, connect the scan tool to the data link connector (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.
- See COMMUNICATIONS NETWORK.

5. 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.
- See COMMUNICATIONS NETWORK.

6. Carry out the network test:
- If the scan tool responds with no communication for one or more modules, See COMMUNICATIONS NETWORK.
- If the network test passes, retrieve and record the continuous memory DTCs.

7. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB.
8. If the DTCs retrieved are related to the concern, see SMART JUNCTION BOX (SJB) DIAGNOSTIC TROUBLE CODE (DTC) INDEX. Diagnostic Trouble Code Descriptions
9. If no DTCs related to the concern are retrieved, see SYMPTOM TROUBLESHOOTING CHART - SECURITY AND LOCKS. Symptom Related Diagnostic Procedures