Initial Inspection and Diagnostic Overview

Inspection and Verification

CAUTION: Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not guarantee confirmation of a fault, and may also cause additional faults in the vehicle being tested and/or the donor vehicle.
1 Verify the customer concern.
2 Visually inspect for obvious signs of damage and system integrity.





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, check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.