P03CCCylinder 6 Pressure Too Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Some diesels have a combustion pressure sensor in the glow plug; the engine module uses it to control injection for each cylinder. This code concerns cylinder 6. P03CC means the pressure measured in the cylinder is lower than expected while the sensor itself is electrically fine. No manufacturer document available to us describes the code; GM patents show how such an evaluation works: peak and minimum pressure are compared with limits and with a motoring pressure calculated from manifold pressure and compression ratio, and the ratio of measured to motoring pressure is compared between cylinders. A low value can mean weak combustion or compression – leaking valve, worn rings, leaking glow plug seat, an injector delivering too little – or a sensor drifting downwards. The usual consequence is rough running and more smoke.
- What you may notice
- Check engine light on
- Lack of power, rough running, possibly misfire on this cylinder
- More smoke
- Likely causes
- PossibleCompression loss (valve, piston rings, leaking glow plug seat)
- PossibleInjector delivering too little or coked
- PossibleSensor drifting downwards (deposits)
- RareMisfire or partial combustion
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.