Glow Plug Control Module Malfunction
The P064C code indicates a malfunction in the glow plug control module, which manages the glow plugs in diesel engines to aid cold starts. This module controls the timing and duration of glow plug activation. When it fails, the engine may have difficulty starting in cold weather, and the check engine light will illuminate. The issue can stem from electrical faults, module failure, or wiring problems.
1. Most Common Causes
- Faulty glow plug control module (GPCM)
- Corroded, damaged, or high-resistance wiring or connectors in the GPCM circuit
- One or more failed glow plugs overloading the module
- CAN communication issue between the GPCM and the ECU
- Low voltage or charging system/battery fault
- Incorrect module software or calibration
2. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Check engine light on
- Excessive white smoke on startup
- Engine misfire or rough idle
3. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P064C is present.
Step 2: Inspect glow plug control module fuse and relay.
Step 3: Check wiring and connectors for damage or corrosion.
Step 4: Test glow plug resistance and power supply.
Step 5: Replace glow plug control module if all else checks out.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive, but starting may be difficult in cold weather. It's best to repair promptly to avoid being stranded.
How much does it cost to fix?▼
Typically $150-$400 including parts and labor, depending on the vehicle and module location.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.