P0278
Cylinder 6 Contribution/Balance
Fuel injectors / cylinder balance
Generic OBD-II
High
What it means
P0278 means the ECM has determined that cylinder 6 isn't contributing its expected share of power compared with the other cylinders. This balance fault usually points to a fueling problem — a worn, clogged, or leaking injector — or a mechanical weakness such as low compression on that cylinder. The engine runs unevenly and may misfire.
High
Can I keep driving? Drivable short-term, but cylinder 6 is underperforming — expect rough running and possible misfire, and get it checked before it worsens.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or vibration
- Misfire or hesitation
- Reduced power
- Uneven running, possible smoke on a diesel
Common causes
Most likely first
- Worn, clogged, or leaking cylinder 6 injectorLikely
- Low compression or a mechanical issue on cylinder 6Common
- Fuel-delivery problem (pressure or filter) affecting that cylinderCommon
- Wiring or connector fault at the injectorLess often
- Intake or vacuum leak near cylinder 6Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for a cylinder-6 misfire (P0306) or injector codes.
- Compare per-cylinder injector data and fuel trims with a scan tool.
- Test, clean, or replace the cylinder 6 injector.
- Run a compression test if the fueling checks out.
- Repair any wiring faults, then clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P0278?+
For short trips, yes, but cylinder 6 isn't pulling its weight, so the engine runs rough and may misfire. Prolonged misfire can harm the catalytic converter, so address it soon.
Can I just clear P0278?+
It returns until the weak cylinder is fixed. Diagnose the injector or mechanical cause instead of clearing it.
Related codes
Often seen with P0278
Read & clear P0278 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