A third boost pressure sensor, C, only makes sense on engines with several charging stages or chargers – for example a supercharger feeding a turbocharger, or a two-stage turbo system – where pressure is measured between the stages as well as ahead of the throttle. Which location carries the letter C is up to the manufacturer. P25F2 is the general circuit fault of this sensor, without separating low, high or implausible signals (those are P25F3 to P25F5); a networked sensor C would report lost communication as U060D instead. No manufacturer documents P25F2 publicly. For sensor A, GM-built Saab engines check the circuit all the time while the ignition is switched on and fall back to mechanical base boost with a clear loss of power, which is the likely reaction here as well.
Medium severity. Can I keep driving?Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
Symptoms
- Check engine lamp on
- Reduced power, boost limited to base level
Most likely causes
- Loose, corroded or oily connector at boost sensor C
- Signal, 5 V reference or ground wire damaged
- Boost sensor C failed internally
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P25F2 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 5: Speed and idle
- F2: Specific fault in that system
Frequently asked questions
Can I keep driving with code P25F2?
Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
What causes code P25F2?
The most common causes are: loose, corroded or oily connector at boost sensor C; signal, 5 V reference or ground wire damaged; boost sensor C failed internally.
Related codes
- P25F3Turbocharger/Supercharger Boost Sensor C Circuit Range/Performance
- P25F4Turbocharger/Supercharger Boost Sensor C Circuit Low
- P25F5Turbocharger/Supercharger Boost Sensor C Circuit High
- U060DLost Communication With Turbocharger/Supercharger Boost Sensor C
- P0235Turbocharger/Supercharger Boost Sensor A Circuit
- P0239Turbocharger/Supercharger Boost Sensor B Circuit
Sources
- law.cornell.edu: 13 CCR 1968.2
- saabwisonline.com: dtc p0237 or p0238 llu
- en.wikipedia.org: Twincharger
- en.wikipedia.org: MAP sensor
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.