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 checked and/or the donor vehicle.
NOTE:
Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
- Verify the customer concern.
- Visually inspect for obvious signs of mechanical and electrical damage.VISUAL INSPECTION
Mechanical Electrical - Engine oil level
- Cooling system coolant level
- Fuel level
- Fuel contamination/grade/quality
- Exhaust gas recirculation (EGR) valves
- Fuses
- Wiring harness
- Loose or corroded electrical connectors
- Ignition coils
- Sensor(s)
- Engine Control Module (ECM)
- Transmission Control Module (TCM)
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.