Inspection and verification
1. Make sure the customer's complaint is valid.
2. Visually inspect for obvious electrical problems.
Electrical Factors |
3. If an obvious cause of a problem you identified or described by a customer is found, resolve 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
Symptom | Possible reason | Actions |
Bad start (extreme weather conditions) | Check the wiring harnesses at the glow plugs and where they connect to the main wiring harness. Refer to the electrical manual. Check for glow plug related DTCs. The fuel system cycles the fuel until operating temperature is reached to reduce this possibility. | |
High emissions when engine is cold | Post-heating phase not working | Check the wiring harnesses at the glow plugs and where they connect to the main wiring harness. Refer to the electrical manual. Check for glow plug related DTCs. The post-heating phase must operate when the engine temperature is below 50 degrees C and the engine speed is below 2,500 rpm. |
High NVH cold performance | Post-heating phase not working | Check the wiring harnesses at the glow plugs and where they connect to the main wiring harness. Refer to the electrical manual. Check for glow plug related DTCs. The post-heating phase must operate when the engine temperature is below 50 degrees C and the engine speed is below 2,500 rpm. |
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.
DTCs | Description | Possible reasons | Actions |
P038300 | Glow Plug Control Module Control Circuit Low Voltage | Refer to the electrical manual and check the electrical circuit. Check relay operation. Repair/replace as needed. | |
P038400 | High voltage in the control circuit of the glow plug control module | Refer to the electrical manual and check the electrical circuit. Check relay operation. Repair/replace as needed. | |
P067000 | Glow plug control module - open control circuit | Check the glow plug relay circuits. Refer to the electrical manual. Check relay operation. Activate the relay and listen to "click". Repair/replace as needed. Clear DTCs and check for correct operation. |
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