C0579Brake Booster Temperature Sensor B Circuit Low
- Generic OBD-II code · Chassis
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- Electromechanical brake boosters watch the heat in their motor and power electronics so they can scale back assist before damage; a Hitachi Astemo patent, for example, describes one sensor on the motor and one in the drive circuit, with assist limited above set temperatures. GM reads two temperature channels from its booster: A under P25C6/P25C7, B under C0579/C057A. C0579 means channel B reads too low, which GM treats as a short to ground: under 0.03 V on five consecutive checks within 0.6 s in the 2023 and 2025 tables, Type B with MIL after two trips. GM's 2019 Cadillac XT4 tables use the same voltage with two detections between about 7 and 124 mph, but as Type C without MIL. The booster then runs a protective strategy.
- What you may notice
- Check engine light after two trips (GM 2023/2025), brake warning
- Brake assist may be reduced as a precaution
- Booster temperature B shows an implausible value on the scan tool
- Likely causes
- LikelyTemperature signal B shorted to ground inside the booster or its harness
- PossibleThermistor shorted, e.g. after overheating
- RareFault in the booster control electronics reading the channel
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.