P25A1Turbocharger B Boost Control Position At High Limit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P25A1 is set when the boost control for turbocharger B is pinned at its upper limit and still cannot bring pressure down to the requested value, so the second charger overshoots. Like P25A0 it is limited to engines with two individually controlled chargers, and no manufacturer has published its own criteria for P25A1. CARB 13 CCR 1968.2 asks the OBD system to detect boost control that has exhausted its authority as well as boost that climbs above the commanded level. Ford's overboost monitor for turbocharger A (P259F) gives a sense of scale: 120 kPa above target for about 10 s on the 6.7 L diesel. A wastegate or vane mechanism stuck toward closed, a blocked or misrouted control line, or false sensor readings are typical. Engines usually limit power to protect the turbo.
- What you may notice
- Engine warning lamp on
- Power cut-out at high load
- Likely causes
- LikelyWastegate or vanes of charger B stuck toward closed
- PossibleBlocked, leaking or misrouted control line of actuator B
- RareBoost pressure sensor giving wrong values
- 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 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.