P235F code meaning
Cylinder 11 Pressure Sensor Circuit High
Powertrain system Generic code P23xx codes Check engine light
What P235F means
P235F is logged when the cylinder 11 pressure sensor signal remains above its plausible maximum. Only twelve-cylinder engines have this cylinder, and no maker documents the code; the Saab 9-5 diesel serves as the model with P0398 for cylinder 1, a Type B code that needs more than 2 s over the threshold. In that wiring layout three faults produce a high reading: an open low reference, an open signal wire and a reference or signal shorted to battery voltage. Saab's test plan therefore measures less than 5 Ohm between the low reference and ground, and it requires infinite resistance between every sensor terminal and the plug body – broken insulation inside the glow plug would also distort the signal. The cylinder runs on without pressure feedback; P235E is the opposite case.
P235F at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P235F
- Check engine light after two trips
- Implausibly high fixed pressure value for cylinder 11
Common causes of P235F
- Most likelyLow reference (ground) wire of the sensor open
- PossibleSignal wire interrupted or connector off
- Less likelyReference or signal shorted to battery voltage
- Less likelyInsulation failure between sensor terminals and plug body
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder pressure sensor glow plugSensor wiringEngine control module
What each part of P235F means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| 5F | The exact fault in that area. |
What to do next
- Note P235F and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P235F
What does P235F mean?
P235F means "Cylinder 11 Pressure Sensor Circuit High". P235F is logged when the cylinder 11 pressure sensor signal remains above its plausible maximum. It is a generic code, so it means the same on every make.
Is it safe to drive with P235F?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P235F fail an emissions test?
Yes, it can. P235F is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P235F to fix?
Difficulty: medium. A typical repair takes 0.5 to 3.5 hours of work. This is a job for a workshop.
Will P235F clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.