P25FB
Turbocharger/Supercharger Bypass Valve C Control Circuit Range/Performance
The third bypass valve current does not match the commanded value within tolerance. Drifted coil resistance or high-resistance contact in the connector.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
Common causes
Ordered by how often each turns out to be the cause.
- Coil resistance changed by thermal stressPossible
- High-resistance contact in the valve connectorPossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- Bypass Valve C
- Bypass Solenoid
P25FB 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.