P02C6
Cylinder 12 - Fuel Trim at Max Limit
Fuel & air metering
Generic OBD-II
High
What it means
P02C6 means the engine controller has had to add the maximum amount of fuel it can to cylinder 12 to keep it running correctly — its fuel trim has hit the limit. That means cylinder 12 is running lean, usually from an air leak, a restricted injector, or low fuel pressure. The engine idles rough and can hesitate until the underlying lean cause is fixed.
High
Can I keep driving? You can usually drive, but cylinder 12 is running lean and rough. Sustained lean misfire 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
- Slightly poorer fuel economy
Common causes
Most likely first
- Vacuum or intake leak affecting cylinder 12Likely
- Clogged or weak fuel injector on cylinder 12Common
- Low fuel pressure limiting deliveryCommon
- Exhaust leak upstream of the oxygen sensor skewing trimLess often
- Low compression on cylinder 12Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the max fuel trim is specific to cylinder 12.
- Inspect for vacuum and intake leaks near cylinder 12; smoke-test if needed.
- Check fuel pressure and the cylinder 12 injector's flow (clean or replace if restricted).
- Look for exhaust leaks ahead of the oxygen sensor.
- If fueling and air are good, compression-test cylinder 12. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P02C6?+
For short trips, but a lean, misfiring cylinder runs rough and can damage the catalytic converter over time. Have it fixed promptly.
Can I just clear P02C6?+
It will return until the lean condition on cylinder 12 — usually a leak or a fuel-delivery issue — is corrected.
Related codes
Often seen with P02C6
Read & clear P02C6 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