P03CE: Cylinder 6 Pressure Variation Low

What does P03CE 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 6. P03CE means the swing of the pressure signal is too small. The only manufacturer we found using this code family, GM's European 2.0 CDTI four-cylinder diesel (Saab 9-5, 2010), uses 'pressure variation too low' for cylinders 1 to 4: signal outside its range for more than 0.2 s with the engine running; what exactly is measured, Saab does not explain – presumably the signal barely responds, for example because a coked glow rod no longer transmits the pressure. 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. Usually there are no noticeable symptoms.

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

Symptoms

• Check engine light on
• Usually no noticeable symptoms
• Possibly rough running or combustion noise because control is off

Common causes

• High Pressure-sensing glow plug faulty or coked (glow rod stuck)
• Medium Contact resistance in connector or ground
• Low Actual compression loss or misfire in the cylinder

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