C0279Brake Booster Boost Sensor Circuit Malfunction
- Generic OBD-II code · Chassis
- How the car detects it
- C0279 is absent from every publicly available J2012 list, and no maker describes it as a booster sensor code. GM does use the number: its bulletin PIP5094 names it among the chassis keywords for 2014 and older cars and light trucks, and the GM brake code chart published by AA1Car renders it as Powertrain Configuration Not Valid, meaning the brake module received engine or driveline data it was not set up for. The part in the title reports how much vacuum or boost pressure the brake booster holds. On the 2011 Saab 9-4X the brake module feeds such a sensor with 5 V and switches an electric vacuum pump on when the reading drops; Bosch uses the same signal for start/stop and brake assist. With the circuit faulty, the module loses that reading.
- What you may notice
- Brake or ABS warning lamp on
- Electric vacuum pump runs constantly or not at all
- Start/stop or brake assist unavailable
- Likely causes
- PossibleOpen or shorted 5 V supply, signal or ground wire of the booster sensor
- PossibleBooster pressure sensor failed or its grommet leaking
- RareBrake module not configured for the fitted engine or driveline (GM meaning of the number)
- Repair
- Medium · Usually a job for a workshop.Typical cost: €30 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.