P0681
Cylinder 11 Glow Plug Circuit/Open
Glow plug / diesel preheat
Generic OBD-II
High
What it means
P0681 is a diesel code meaning the ECM has detected an open circuit in the glow plug for cylinder 11. Glow plugs pre-heat the combustion chamber for cold starting, so a single open plug mainly causes hard cold starts and rough, smoky running until the engine warms up — a warm engine is unaffected.
High
Can I keep driving? You can usually drive once warm, but expect hard cold starts and rough cold running until the glow plug circuit is repaired.
Common symptoms
What you'll notice
- Hard or slow starting, especially in cold weather
- Rough idle and white smoke on a cold start until warm
- Glow plug (coil) warning light or check-engine light on
- Reduced power in cold weather
Common causes
Most likely first
- Failed (open) glow plug on cylinder 11Likely
- Open or shorted wiring/harness to the cylinder 11 glow plugCommon
- Corroded or loose electrical connectorCommon
- Faulty glow plug control moduleLess often
- Faulty ECM/PCM driver (less common)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fault is on cylinder 11.
- Measure the cylinder 11 glow plug resistance — an open plug reads infinite and needs replacing.
- Inspect the harness and connector for an open circuit or corrosion.
- Check the glow plug control module output and its power/ground.
- Repair the open, clear the code, and retest a cold start.
FAQ
Quick answers
Is it safe to drive with P0681?+
Usually yes once warm, but cold starts will be difficult and it may run rough and smoke. It won't harm the engine, but fix it before cold weather.
Can I just clear P0681?+
It returns the next time the ECM checks the glow plug circuit. The open plug or wire has to be repaired for the code to stay cleared.
Related codes
Read & clear P0681 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX