P069B
Cylinder 9 Glow Plug Control Circuit High
Glow plug / diesel preheat
Generic OBD-II
High
What it means
P069B is a diesel code meaning the control circuit that drives the cylinder 9 glow plug is reading high — an open circuit or a short to voltage. 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 circuit 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
- Open or short-to-voltage in the cylinder-9 glow-plug control circuitLikely
- Failed or open glow plug on cylinder 9Common
- 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 9; note any companion glow-plug codes.
- Inspect the cylinder-9 glow-plug wiring for an open or a short to voltage.
- Measure the glow plug's resistance and compare it to the others.
- Test the glow-plug control-module driver; replace the plug or repair the wiring, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P069B?+
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 P069B?+
It returns after the next cold start unless the control-circuit fault or failed plug is repaired.
Related codes
Often seen with P069B
Read & clear P069B 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