Glow Plug Control Module Malfunction
The P064C code indicates a malfunction in the glow plug control module, which manages the glow plugs during cold starts in diesel engines. This module controls the pre-glow and post-glow cycles to ensure proper combustion. A failure can lead to hard starting, excessive smoke, and reduced engine performance, especially in cold weather.
01. Most Common Causes
- Faulty glow plug control module
- Wiring or connector issues in the glow plug circuit
- Blown fuse or relay for the glow plug system
- Corrosion or poor ground connections
02. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Excessive white or gray smoke from exhaust on startup
- Check Engine Light illuminated
- Rough idle or misfire during cold starts
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm code P064C and check for related codes (e.g., P0670-P0678).
Step 2: Visually inspect the glow plug control module, wiring, and connectors for damage, corrosion, or loose connections.
Step 3: Test the glow plug control module power supply and ground circuits with a multimeter.
Step 4: Check the glow plug resistance individually using a multimeter (typically 0.5-2 ohms).
Step 5: If all else is fine, replace the glow plug control module and clear the code.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances, especially in cold weather, as it can cause hard starting, increased emissions, and potential engine damage from incomplete combustion.
How much does it cost to fix?▼
The cost typically ranges from $200 to $600, including parts (glow plug control module $100-$300) and labor ($100-$300), depending on vehicle make and model.