P0680
Cylinder 10 Glow Plug Circuit/Open
Diesel glow plug / preheat
Generic OBD-II
High
What it means
P0680 is a diesel code for an open circuit on the cylinder 10 glow plug — typically a burned-out glow plug or a broken wire, seen on larger V8/V10 diesels. Glow plugs preheat the cylinder for starting, so the effects are hard cold starts, rough warm-up, and white smoke rather than a warm no-start.
High
Can I keep driving? Usually yes, but expect hard cold starts and rough cold running until the cylinder 10 glow plug circuit is repaired.
Common symptoms
What you'll notice
- Hard starting, especially in cold weather
- Rough idle or a miss until the engine warms up
- White or grey exhaust smoke on a cold start
- Check-engine or glow-plug warning light on
Common causes
Most likely first
- Failed cylinder 10 glow plug with an open elementLikely
- Open or broken wiring in the glow plug circuitCommon
- Loose or corroded connector at the glow plug or moduleCommon
- Faulty glow plug control moduleLess often
How to diagnose & fix
Work through it in order
- Scan and confirm the open-circuit fault is on cylinder 10.
- Measure the glow plug's resistance; an open reading means it needs replacing.
- Inspect and repair the wiring and connector between the module and the cylinder 10 glow plug.
- Verify the glow plug control module output, then clear and re-test on a cold start.
FAQ
Quick answers
Is it safe to drive with P0680?+
Generally yes in mild weather. A single open glow plug on a large diesel mainly causes hard cold starting and rough warm-up; repair it before cold weather.
Can I just clear P0680?+
It returns on the next cold start unless the open glow plug or its wiring is repaired.
Related codes
Often seen with P0680
Read & clear P0680 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