Powertrain, generic (extended)

P235B Cylinder 10 Combustion Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P235B rates how well cylinder 10 burns, derived from its pressure curve – for instance from the energy each working cycle releases or from how it compares with the other nine cylinders of a V10. No manufacturer documents this code, nor the cylinder-1 equivalent P039E. CARB supplies the background: diesel passenger cars equipped with combustion or combustion quality sensors must, from model year 2010, flag misfire once it reaches 5 % of firings, counted over 1,000 revolutions – far tighter than the continuous-misfire rule other diesels long had to meet. Coked or worn injectors, partial compression loss, intake air leaks or poor fuel degrade combustion. The engine shakes, smoke and consumption rise, and the code tends to appear together with P2357 or P2358 or with the cylinder 10 misfire code P0310.

Likely causes

Coked or worn injector of cylinder 10

Partial compression loss in cylinder 10

Air leak in the intake tract

Poor or contaminated fuel

Symptoms

Check engine light on
Uneven running and vibration
Increased smoke and fuel consumption

Repair estimate

DifficultyHardWorkshop job

Parts and labour€150–2,800

Time1–9 h

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

Parts involved

cylinder pressure sensor glow plugsensor wiringengine control modulefuel injector

References: law.cornell.edu, borgwarner.com.