Cylinder 10 Glow Plug Circuit Malfunction
The P0680 code indicates a fault in the glow plug circuit for cylinder 10. This circuit includes the glow plug itself, wiring, connectors, and the glow plug control module. When the engine control module (ECM) detects an open circuit, short circuit, or excessive resistance in the cylinder 10 glow plug circuit, it sets this code. Glow plugs are essential for cold starting in diesel engines, as they preheat the combustion chamber. A malfunction can cause hard starting, rough idle, and increased emissions, especially in cold weather.
01. Most Common Causes
- Faulty glow plug in cylinder 10
- Open or shorted wiring in the glow plug circuit
- Corroded or loose connector at the glow plug
- Failed glow plug control module or relay
02. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Rough idle or misfire after start-up
- Check Engine Light illuminated
- Excessive white smoke from exhaust on cold start
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P0680 and check for related codes.
Step 2: Visually inspect the glow plug wiring and connector for cylinder 10 for damage, corrosion, or looseness.
Step 3: Measure resistance of the cylinder 10 glow plug; compare to manufacturer specs (typically 0.5-2 ohms).
Step 4: Test voltage at the glow plug connector with the ignition on; should be battery voltage.
Step 5: If wiring and glow plug are good, test the glow plug control module or relay output for cylinder 10.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances in mild weather, but cold starts will be difficult and may cause excessive smoke. Prolonged driving may damage the catalytic converter or cause other issues. It's best to repair promptly.
How much does it cost to fix?▼
Replacing a single glow plug typically costs $50-$150 including parts and labor. If the control module or wiring needs repair, costs can be higher.