P03A5Cylinder 2 Pressure Too High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- 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 2. P03A5 means the pressure measured or calculated for the cylinder is higher than expected. It is documented by code at Audi, surprisingly on a petrol engine: on the 2015 S3 (2.0 TFSI, engine CYFB) the four 'pressure too high' codes came on with the EPC lamp, usually together with misfire codes P0300–P0304 and the manufacturer code for hiding a cylinder; the cause was a software fault that mis-detected misfire, and a software update fixed it. How Audi determines the pressure, the bulletin does not say. On diesels with pressure-sensing glow plugs GM patents describe a peak pressure above its limit – too much or too early injection, or a sensor drifting upwards. If the cylinder is shut off, power drops noticeably.
- What you may notice
- EPC or check engine light on
- Misfire codes, possibly a cylinder shut off with noticeable loss of power
- Rough running
- Likely causes
- LikelyEngine module software (Audi S3 2015, engine CYFB)
- PossibleInjector delivering too much or dripping
- PossibleSensor drifting upwards (diesel pressure-sensing glow plug)
- RareKnock or pre-ignition on a petrol engine
- 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: €80 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.