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. The Engine Control Module (ECM) monitors the current flow through the glow plug circuit; if it detects an open or short circuit, or resistance outside the expected range, it sets this code. This is common in diesel engines with multiple glow plugs, especially in cold weather.
1. Most Common Causes
- Faulty glow plug in cylinder 10 (internal open circuit)
- Damaged, corroded, or shorted wiring or connectors in the glow plug circuit for cylinder 10
- Failing glow plug control module
- Blown fuse or fusible link in the glow plug power supply circuit
- Defective PCM (rare)
2. Symptoms You Will Notice
- Hard starting, especially in cold weather
- Check Engine Light illuminated
- Rough idle or misfire on cylinder 10
- Excessive white smoke on startup
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P0680 and check for other related codes.
Step 2: Visually inspect the glow plug wiring and connector for cylinder 10 for damage or corrosion.
Step 3: Measure resistance of the glow plug at cylinder 10; compare to specifications (typically 0.5-2 ohms).
Step 4: Check for voltage at the glow plug connector during the glow cycle (usually 12V).
Step 5: If wiring and plug are okay, test the glow plug control module output for cylinder 10.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe to drive short distances in mild weather, but starting may be difficult in cold conditions. Prolonged driving with a faulty glow plug can cause incomplete combustion, leading to carbon buildup and potential damage to the cylinder.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a single glow plug replacement, including parts and labor. If the control module or wiring needs repair, costs can be higher.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.