P25F5 code meaning
Turbocharger/Supercharger Boost Sensor C Circuit High
Powertrain system Generic code P25xx codes Check engine light
What P25F5 means
P25F5 reports a signal from boost sensor C above the highest plausible value. Since the voltage climbs with pressure, a reading at the top end usually means an electrical fault: the signal shorted to 5 V or battery voltage, an open sensor ground, or an open signal wire where the input is pulled up. The limits differ widely by engine – for sensor A, Saab's GM-based 1.6 litre sets its code above 4.8 V (4 s at a stretch or 50 s cumulated, type C without lamp), whereas the 2.0 litre already flags a reading above 3.9 V lasting 5 s as a type B fault. No manufacturer documents these limits for sensor C. Because the engine would believe boost is excessive, it typically cuts boost control. P25F4 is the opposite fault.
P25F5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P25F5
- Check engine lamp on, depending on the manufacturer
- Reduced power, boost cut back
Common causes of P25F5
- Most likelySensor ground open or high resistance
- PossibleSignal wire shorted to 5 V or battery voltage
- PossibleBoost sensor C failed internally
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Boost pressure sensor cWiring harness
What each part of P25F5 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| F5 | The exact fault in that area. |
What to do next
- Note P25F5 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 P25F5
What does P25F5 mean?
P25F5 means "Turbocharger/Supercharger Boost Sensor C Circuit High". P25F5 reports a signal from boost sensor C above the highest plausible value. It is a generic code, so it means the same on every make.
Is it safe to drive with P25F5?
Drive gently and only to a workshop. With P25F5 the car can go into limp mode (reduced power) to protect itself.
Will P25F5 fail an emissions test?
Yes, it can. P25F5 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 P25F5 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P25F5 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.