P0672
Cylinder 2 Glow Plug Circuit/Open
Glow plug / diesel preheat
Generic OBD-II
High
What it means
P0672 is a diesel code meaning the glow-plug circuit for cylinder 2 is open — the module isn't seeing the expected current through that plug. Glow plugs preheat the combustion chamber for cold starting, so a single open plug mainly shows up as harder cold starts and rough running until the engine warms, not as a total no-start.
High
Can I keep driving? Usually drivable once warm, but expect hard cold starts and rough cold running until the plug is fixed — repair before winter.
Common symptoms
What you'll notice
- Hard starting when the engine is cold
- Rough idle or a misfire-like stumble until the engine warms up
- White or excess smoke from the exhaust on a cold start
- Glow-plug or check-engine warning light on
Common causes
Most likely first
- Failed (open) glow plug on cylinder 2Likely
- Open or broken wiring/connector to that glow plugCommon
- Corroded or loose glow-plug connectionCommon
- Faulty glow-plug control module, or rarely the ECMLess often
How to diagnose & fix
Work through it in order
- Scan and confirm the code is cylinder 2; check for other glow-plug codes.
- Measure the cylinder-2 glow plug's resistance; an open plug reads infinite.
- Inspect the plug's wiring and connector for breaks or corrosion.
- Check the glow-plug control-module output, then replace the failed plug or repair wiring and re-test.
FAQ
Quick answers
Is it safe to drive with P0672?+
In mild weather usually yes — the engine still runs on the heat from its other cylinders. In cold weather expect hard starts and rough warm-up; fix it before winter.
Can I just clear P0672?+
It will come back after the next cold-start cycle unless the open glow plug or its wiring is repaired.
Related codes
Often seen with P0672
Read & clear P0672 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