P029C

Cylinder 1 - Injector Restricted

Q: 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.

Q: Can I just clear P029C?

It will return until the restricted injector on cylinder 1 is cleaned or replaced.

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.

Real-world scan data

Seen in

174

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P029C scans

P1646in 66.7% of scans

P02A4in 56.3% of scans

P02A8in 46.0% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

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.

Read & clear P029C yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX