P06C5
Cylinder 1 Glow Plug Incorrect
Glow plug / diesel preheat
Generic OBD-II
High
What it means
P06C5 is a diesel code meaning the glow-plug system detected an incorrect or implausible condition for cylinder 1 — the plug's electrical behavior doesn't match what's expected. Glow plugs preheat the cylinder for cold starting, so this usually shows up as harder cold starts and rough cold running rather than a no-start.
High
Can I keep driving? Usually drivable once warm, but expect hard cold starts and rough cold running until the glow plug is fixed.
Common symptoms
What you'll notice
- Hard starting in cold weather
- Rough idle or hesitation until the engine warms up
- White or excess exhaust smoke on a cold start
- Glow-plug or check-engine light on
Common causes
Most likely first
- Failed or wrong-type glow plug on cylinder 1Likely
- High-resistance or partly shorted glow plugCommon
- Damaged wiring or connector at the glow plugCommon
- Faulty glow-plug control moduleLess often
How to diagnose & fix
Work through it in order
- Scan and confirm cylinder 1; note any companion glow-plug codes.
- Measure the cylinder-1 glow plug's resistance and compare it to the others.
- Confirm the correct glow-plug part is fitted for the engine.
- Inspect the wiring and connector, test the control-module driver, then replace the plug as needed and re-test.
FAQ
Quick answers
Is it safe to drive with P06C5?+
In mild weather usually yes, but cold starts will be hard and the engine rough until it warms. Repair it before cold weather.
Can I just clear P06C5?+
It returns after the next cold start unless the incorrect or failed glow plug is replaced.
Related codes
Often seen with P06C5
Read & clear P06C5 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