Initial Inspection and Diagnostic Overview

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

VISUAL INSPECTION CHART
^ Central Junction Box (CJB)
^ Damaged wiring harness
^ Loose or corroded connector(s)
^ Circuitry
^ Generic Electronic Module (GEM)

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 scan tool does not power up:
^ check that the program card is correctly installed.
^ check the connections to the vehicle.
^ check the ignition switch is in the RUN position.
^ If the scan tool still does not power up, refer to the scan tool manual.

5. Carry out the DATA LINK DIAGNOSTICS test. If the scan tool responds with:
^ CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to Module Communication Network (Information Bus).
^ NO RESPONSE/NOT EQUIP for GEM, go to Pinpoint Test A.
^ SYSTEM PASSED, retrieve and record the continuous Diagnostic Trouble Codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the GEM.

6. If the DTCs retrieved are related to the concern, go to the GEM DTC Index to continue diagnostics. Diagnostic Trouble Code Tests and Associated Procedures
7. If no DTCs related to the concern are retrieved, refer to the appropriate system to continue diagnostics.