Initial Inspection and Diagnostic Overview

1. The interior lighting system is a GEM/CTM controlled system; refer to Multifunction Electronic Control Module.

NOTE: The Generic Electronic Module (GEM)/Central Timer Module (CTM) must be reconfigured upon replacement. Refer to the scan tool help screen on the configuration card to program the tire size and axle ratio; refer to Module Communications Network (Information Bus).

2. Verify the customer concern by operating the system in question.
3. Visually inspect for obvious signs of mechanical and electrical damage.







VISUAL INSPECTION CHART

4. If the concern remains after the inspection, connect the scan tool to the Data Link Connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan tool menu. If the scan 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 scan tool still does not communicate with the vehicle, refer to the scan tool manual.
6. Carry out the DATA LINK DIAGNOSTIC TEST. Pinpoint Test PC (Precheck)
If the scan tool responds with:
^ CKT914, CKT915 orCKT7O = ALL ECUS NO RESP/NOT EQUIP, refer to Module Communications Network (Information Bus).
^ NO RESP/NOT EQUIP for GEM/CTM, go to Pinpoint Test A. Test A: No Communication With The GEM/CTM
^ SYSTEM PASSED, retrieve and record the continuous Diagnostic Trouble Codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the GEM/CTM.

B1302-B1347, P0500:

7. If the DTCs retrieved are related to the concern, go to the GEM/CTM Diagnostic Trouble Code (DTC) Index to continue diagnostics. GEM/CTM Diagnostic Trouble Code (DTC) Index
8. If no DTCs related to the concern are retrieved, proceed to the Symptom Chart to continue diagnostics. Symptom Related Diagnostic Procedures