P029C
Cylinder 1 - Injector Restricted
Fuel injector
Generic OBD-II
High
What it means
P029C means the engine controller has detected that the fuel injector on cylinder 1 is restricted — it can't flow the fuel the ECM is asking for, usually because of clogging or deposits. That cylinder runs lean and misfires, so the engine idles rough and loses a little power. It's typically a dirty or clogged injector rather than an electrical fault.
High
Can I keep driving? You can usually drive, but cylinder 1 runs lean and rough. Sustained misfiring can harm the catalytic converter, so fix it soon.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or a miss from one cylinder
- Hesitation and reduced power
- Harder starting, especially when cold
Common causes
Most likely first
- Clogged or restricted fuel injector on cylinder 1Likely
- Contaminated or poor-quality fuel leaving depositsCommon
- Debris from a dirty fuel filter or tank reaching the injectorCommon
- Low fuel pressure limiting flow through the injectorLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the lean/restriction is specific to cylinder 1.
- Check fuel pressure and replace a dirty fuel filter.
- Try a quality injector-cleaning treatment or professional injector cleaning.
- If flow is still restricted, remove and flow-test the cylinder 1 injector; replace it if it won't clear.
- Confirm fuel quality. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P029C?+
For short trips, but the lean, misfiring cylinder makes the engine run rough and can damage the catalytic converter over time. Fix it promptly.
Can I just clear P029C?+
It will return until the restricted injector on cylinder 1 is cleaned or replaced.
Related codes
Often seen with P029C
Read & clear P029C 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