P25FD
Turbocharger/Supercharger Bypass Valve C Temperature Too High
The third bypass valve has reached over-temperature. Either coil duty cycle is too high for too long, or cooling air flow around the valve is restricted.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Common causes
Ordered by how often each turns out to be the cause.
- Sustained high duty cycle from charge balancing strategyCommon
- Cooling air channel blocked by debrisPossible
Parts involved
- Bypass Valve C
- Bypass Solenoid
P25FD is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.