P0235
Turbocharger/Supercharger Boost Sensor "A" Circuit
The ECU detected an electrical fault in the primary (A) boost pressure sensor circuit. The signal does not match plausibility checks against MAP, RPM, and load. With no boost feedback, the ECU typically limits boost via the wastegate.
- Check engine light: Yes
- Emissions related: Yes
- 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.
- Boost pressure sensor failedCommon
- Wiring or connector faultPossible
Parts involved
- Boost Pressure Sensor
- Boost Sensor Wiring
- Turbocharger
P0235 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.