Powertrain, generic (extended)

P236C Cylinder 12 Pressure Too High

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

P236C flags combustion pressure in cylinder 12 above its allowed value. A public twelve-cylinder application does not exist. That a code of this kind need not involve a pressure sensor at all is shown by its cylinder-1 to -4 relatives P039B, P03A5, P03AF and P03B9 on Audi's 2015 S3 with the CYFB petrol engine: faulty ECM software logged misfires in its primary detection window, switched on the EPC lamp and shut a cylinder off (P130A00); new ECM software solved it. On a diesel with real pressure sensing, a dripping injector, too much pilot fuel or a sensor drifting upward are the usual suspects. High peaks strain pistons, rings and gasket, so cutting the cylinder with reduced power is a plausible protective reaction.

Likely causes

Engine control software error (update available)

Injector dripping or delivering too much pilot fuel

Pressure sensor drifting upward

Symptoms

EPC or check engine lamp on
Loss of power when the cylinder is switched off
Harder combustion noise

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€80–1,500

Time0.5–5 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: static.nhtsa.gov, law.cornell.edu, borgwarner.com.