P236ECylinder 12 Pressure Variation High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P236E means the pressure signal of cylinder 12 scatters more than the ECM tolerates, either within one cycle or from one cycle to the next. No manufacturer publishes the code; the reference is Saab's P039D for cylinder 1, a Type B fault that needs only 0.2 s outside its window. Two groups of causes are possible. Electrical ones make the trace noisy: interference coupled into the signal wire, or a low-reference contact whose resistance changes with vibration. Combustion-related ones make the cylinder really unsteady: an injector whose delivery varies shot by shot, air in the fuel, or a sticking valve. Live data that are noisy even on overrun, when nothing burns, point to the electrical side. Drivers notice slight roughness at most.
- What you may notice
- Check engine light on
- Occasional slight roughness
- Likely causes
- PossibleInterference on the signal wire
- PossibleLow-reference contact with changing resistance
- PossibleInjector delivery varying from shot to shot
- RareAir in the fuel supply
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.