P06C7
Cylinder 3 Glow Plug Incorrect
Glow plugs (diesel)
Generic OBD-II
High
What it means
P06C7 means the engine computer sees the cylinder 3 glow plug behaving outside its expected range — often the wrong plug fitted, an out-of-spec element, or a high-resistance connection. Glow plugs preheat the combustion chamber for cold starting, so this typically shows up as hard cold starts, rough running until warm, and white exhaust smoke.
High
Can I keep driving? Usually driveable in mild weather, but expect hard cold starts and rough cold-running until the glow plug circuit is repaired.
Common symptoms
What you'll notice
- Hard starting, especially in cold weather
- Rough running or a stumble right after a cold start
- White or blue exhaust smoke on a cold start
- Check-engine light (and often the wait-to-start/glow-plug light) on
Common causes
Most likely first
- Cylinder 3 glow plug out of spec (resistance or response not as expected)Likely
- Wrong or mismatched glow plug installed on cylinder 3Common
- High-resistance or corroded connection in the cylinder 3 glow plug circuitCommon
- Faulty glow plug control moduleLess often
- Faulty ECM (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fault is on cylinder 3 specifically.
- Measure the cylinder 3 glow plug resistance and compare it against the other plugs; replace if out of spec.
- Confirm the correct glow plug part is fitted for cylinder 3.
- Inspect the wiring and connector for corrosion and high resistance.
- Clear the code and retest with a cold start; if it returns, evaluate the control module and ECM.
FAQ
Quick answers
Is it safe to drive with P06C7?+
In mild weather usually yes, but cold starts will be hard and the engine may run rough until warm. Repair it before cold weather to avoid a no-start.
Can I just clear P06C7?+
You can, but it will return until the mismatched or out-of-spec glow plug is corrected.
Related codes
Often seen with P06C7
Read & clear P06C7 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