P25FATurbocharger/Supercharger Bypass Valve C Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- With P25FA the control line of bypass valve C carries more voltage than the engine module expects for the commanded state. A wire shorted to battery voltage is the classic reason; on a ground-switched valve an open coil or broken lead also lets the line float up to supply level. A short to voltage can make the driver stage overheat and cut out, so the valve is no longer operated at all. On an electric recirculation valve, the effect is that it no longer opens on throttle lift-off and the compressor can surge, with the typical fluttering sound and some stress on the charger. No manufacturer documents P25FA for valve C; GM-based Saab engines monitor the same fault for valve A as part of a continuous type B circuit check. The low-side fault is P25F9.
- What you may notice
- Check engine lamp on
- Fluttering or surging noise when lifting off the throttle
- Likely causes
- LikelyControl wire shorted to battery voltage
- PossibleOpen valve coil on a ground-switched circuit
- RareDamaged output stage in the engine control module
- 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: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.