Powertrain, generic (extended)

P235C Cylinder 11 Pressure Sensor Circuit

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P235C stands for a fault in the circuit of the cylinder 11 combustion pressure sensor without saying whether the signal is too low or too high. A V10 ends at cylinder 10, so only twelve-cylinder engines have an eleventh one. With bank-wise numbering, cylinder 11 is the second-to-last of the second bank, between 10 and 12. Production engines combining twelve cylinders with combustion pressure sensors are not on public record, and no manufacturer documents P235C; the description rests on CARB's circuit monitoring rules and the cylinder-1 counterpart P0395. In Saab's 9-5 diesel the ECM wires each such sensor with a 5 V supply, a ground return and a signal line, and a fault in any of the three can trigger the code. Driving is normally unaffected.

Likely causes

Connector at the cylinder 11 glow plug loose or corroded

Reference, low reference or signal wire damaged

Sensor electronics in the glow plug failed

Symptoms

Check engine light on
No change in how the engine runs

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€50–500

Time0.5–3.5 h

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

Parts involved

cylinder pressure sensor glow plugsensor wiringengine control module

References: law.cornell.edu, saabwisonline.com, en.wikipedia.org.