C057DBrake Booster Temperature Sensor Circuit B Intermittent/Erratic
- Generic OBD-II code · Chassis
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- C057D is meant for a temperature B signal that drops out or jumps for brief moments instead of failing for good – a loose connector pin, a cracked solder joint or a wire breaking under vibration are the classic reasons. No manufacturer publishes a threshold for it. GM's monitors for this channel require several consecutive out-of-range samples (two or five) before storing C0579 or C057A, which filters single spikes; a separate code for unsteady behaviour is not listed in GM's public tables. Thermistor suppliers name mechanical stress, moisture and solder damage as frequent sources of unstable readings. The fault tends to come and go with temperature or road shocks and may return after clearing; while the signal is unreliable the booster can limit assist.
- What you may notice
- Brake warning that appears and disappears
- Temperature B jumping on the scan tool
- Code returns some time after clearing
- Likely causes
- LikelyLoose or fretting pin in the booster connector
- PossibleCracked solder joint of the thermistor on the circuit board
- PossibleMoisture ingress causing leakage currents at the sensor
- Repair
- Hard · Usually a job for a workshop.Typical cost: €60 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.