P03C1Cylinder 5 Pressure Sensor Circuit Intermittent/Erratic
- 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 5. P03C1 means the sensor signal is erratic or drops out for moments – typically a loose contact at the glow plug connector, a chafed harness or sensor electronics unstable with temperature. The only manufacturer we found using this code family, GM's European 2.0 CDTI four-cylinder diesel (Saab 9-5, 2010), uses it for cylinders 1 to 4 as 'circuit erratic': signal outside its range for more than 0.2 s with the engine running. For cylinder 5, which only engines with at least 5 cylinders have, no manufacturer document available to us uses the code; the description follows that logic and CARB. The code often comes and goes.
- What you may notice
- Check engine light on
- Occasionally rough running
- Often no symptoms, the code comes and goes
- Likely causes
- LikelyLoose contact at the glow plug connector
- PossibleChafing or broken wire in the engine harness
- PossibleSensor electronics of the glow plug unstable with temperature
- RareInterference from ground problems
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.