P03DE: Cylinder 8 Pressure Sensor Circuit High

What does P03DE mean?

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 8. P03DE means the sensor signal stays above its upper limit – typically an unplugged connector, an open signal or ground wire, or a short to positive. 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: signal above the threshold for more than 2 s with the engine running, check engine light after two trips, displayed pressure 10,000 kPa. For cylinder 8, which only engines with at least 8 cylinders have, no manufacturer document available to us uses the code; the description follows that logic and CARB. Without the signal, combustion control for this cylinder is switched off.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on (often after two trips)
• Usually barely noticeable – combustion control for the cylinder is switched off
• Possibly rougher running, more noise or slightly higher consumption

Common causes

• High Connector off or loose, signal wire open
• Medium Sensor ground wire open
• Medium Sensor in the glow plug faulty
• Low Signal or reference wire shorted to positive

Likelihood is a general estimate across vehicles; your make and model may differ.