Initial Inspection and Diagnostic Overview
Inspection and Verification1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or 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. If the cause is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
^ check that the program card is correctly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.
5. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool manual.
6. Carry out the data link diagnostics test. If the diagnostic tool responds with:
^ No response/not equipped for all modules, refer to Module Communication Network.
^ No response/not equipped for the lighting control module (LCM), refer to Body Control Systems.
^ System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs, and carry out the self-test diagnostics for the LCM.
7. If the DTCs retrieved are related to the concern, go to the Lighting Control Module (LCM) Diagnostic Trouble Code (DTC) Index to continue diagnostics. [1][2]Diagnostic Trouble Code Descriptions
8. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures
NOTE: For a complete list of lighting control module (LCM) DTCs, refer to Body Control Systems.