Inspection and verification
1. Check the validity of the customer's complaint.
2. Visually inspect for obvious mechanical problems.
Mechanical factors | Electrical Factors |
3. If an obvious cause of a problem you identified or described by the customer is found, correct it before proceeding to the next steps (if possible).
4. Use an approved diagnostic system or scan tool (tester), to retrieve all DTCs before referring to the symptom table or DTC index (DTC).
Clear all DTCs after troubleshooting.
Symptom table
NOTE: See section 303-14 for a more complete symptom table "Electronic engine management system" in the workshop manual.
Symptom | Possible reason | Operation |
Cold start difficulties | For battery information, crankshaft position sensor, fuel system, and purge valve checks, see the appropriate sections in the workshop manual. Check the EGR valve. Refer to the guided diagnostic program on the approved diagnostic system. | |
Engine stalls shortly after starting | Check engine ventilation hoses, PCV, etc. Check the operation of the ECM relay. For MAF sensor checks, ignition system checks, intake system and fuel line details, see the relevant sections of the workshop manual. | |
Poor throttle response | For information on APP, TP, ECT, MAF sensor checks, intake system and transmission information, see the relevant sections of the workshop manual. Check ventilation hoses, PCV, etc. |
DTC index
NOTE: Universal Scan Tools cannot read the listed codes or can only read 5-digit codes. Match the 5 digits from the scan tool with the first 5 digits of the listed 7 digit code to identify the problem (the last 2 digits give additional information read by the diagnostic system approved by the manufacturer).
NOTE: See Section 303-14 for a complete list of ECM DTCs "Electronic engine management system" in the workshop manual.
DTC | Description | Possible reason | Operation |
P040100 | Insufficient flow registered in EGR system A | Check the EGR lines. Check the EGR valve setting, refer to the relevant section of the workshop manual. Refer to the guided diagnostic program for this code on the approved diagnostic system. | |
P048900 | EGR Control Circuit Low Voltage | Refer to the guided diagnostic program for this code on the approved diagnostic system. | |
P049000 | Exhaust Gas Recirculation Control Circuit High Voltage | EGR valve activation circuit short circuit to +battery | Refer to the guided diagnostic program for this code on the approved diagnostic system. |
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