P25F2
Turbocharger/Supercharger Boost Sensor C Circuit
A third boost pressure sensor (C) used on twin-stage or sequential boost systems returns no usable signal. Without it, boost control of the third stage runs open-loop or is disabled.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
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.
- Open sensor element or broken signal wireCommon
- Corroded connector at sensor pigtailPossible
Parts involved
- Boost Pressure Sensor C
- Wiring Harness
P25F2 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.