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) pipes Breather hoses Positive crankcase ventilation valve Fuel level Fuel contamination/grade/quality Throttle body Fuse(s) Loose or corroded electrical connectors Exhaust Gas Recirculation (EGR) valve Engine Control Module (ECM)
- If an obvious cause for an observed or reported condition is found, correct the cause (if possible) before proceeding to the symptom chart.
- 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.
SYMPTOM CHART
| Symptom | Possible Causes | Action |
|---|---|---|
| Difficult to start cold | Battery Crankshaft Position (CKP) sensor Exhaust Gas Recirculation (EGR) valve stuck open Fuel system Evaporative emissions purge valve | For battery information, CKP sensor tests, fuel system and purge valve tests, refer to relevant workshop manual section. Check the EGR valve. Refer to the guided diagnostic routine on the approved diagnostic system. |
| Engine stalls soon after start | Breather system disconnected/restricted Engine Control Module (ECM) relay MAF sensor Ignition system Air filter restricted Air leakage Fuel lines | Check the engine breather hoses, PCV, etc. Check the Engine Control Module (ECM) relay operation. For MAF sensor, ignition system tests, air intake information and fuel line information, refer to relevant workshop manual section. |
| Poor throttle response | APP sensor malfunction TP sensors ECT sensor MAF sensor Transmission malfunction Traction control event Air leakage Breather system disconnected/restricted | For APP, TP, ECT, MAF sensor tests, intake system checks and transmission information, refer to relevant workshop manual section. Check the breather system hoses, PCV, etc. |
DTC INDEX
For a list of Diagnostic Trouble Codes (DTCs) that could be logged on this vehicle, please refer to Diagnostic Trouble Code (DTC) Index - DTC: Engine Control Module 5.0L (PCM) article.