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 or electrical damage.VISUAL INSPECTION
Mechanical Electrical - Exhaust Gas Recirculation (EGR) system
- Breather hoses
- Positive Crankcase Ventilation (PCV) valve
- Fuel level
- Fuel contamination/grade/quality
- Throttle body
- Fuses
- Loose or corroded electrical connectors
- Exhaust Gas Recirculation (EGR) valve
- Engine Control Module (ECM)
- 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.