P03CD Cylinder 6 Pressure Too High

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. P03CD means the pressure measured or calculated for the cylinder is higher than expected. The 'pressure too high' codes are documented only at Audi, for cylinders 1 to 4 of the 2015 S3 petrol engine, where a software fault mis-detected misfire. 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. For cylinder 6, which only engines with at least 6 cylinders have, no manufacturer document available to us uses the code; the description follows that logic and CARB. If the cylinder is shut off, power drops noticeably.

Likely causes

Symptoms

• EPC or check engine light on
• Misfire codes, possibly a cylinder shut off with noticeable loss of power
• Rough running

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, patents.google.com, static.nhtsa.gov.