P25FCTurbocharger/Supercharger Bypass Valve C - Mechanical
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P25FC concerns the valve itself, not its wiring: bypass valve C is electrically in order but does not move as commanded, sticking open, shut or somewhere in between. A valve stuck open lets charge air leak back to the compressor inlet, so boost falls short; one stuck shut cannot relieve pressure when the throttle closes, and the compressor surges audibly. Which of the two cases the engine module can tell apart, and from which signals, is not published; no manufacturer documents valve C publicly, so the comparable codes P2261 (valve A) and P00C4 (valve B) are the closest reference. Deposits from crankcase vapours, a torn diaphragm or a cracked housing are typical. Electrical faults belong to P25F8–P25FB; a stuck valve C may also be reported as P2CD5.
- What you may notice
- Check engine lamp on
- Loud fluttering when lifting off the throttle
- Lack of boost and power
- Likely causes
- LikelyOil and soot deposits from crankcase ventilation jamming the valve
- PossibleTorn diaphragm or broken spring inside the valve
- RareCracked valve housing or leaking seal
- 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: €100 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.