P25C4Brake Booster Temperature Sensor A Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- P25C4 covers the first temperature sensor of an electromechanical brake booster, in which an electric motor and gear set take the place of the vacuum diaphragm, as in Bosch's iBooster. The booster electronics use this value to protect motor and control unit from overheating during long or repeated braking. P25C4 reports an unusable sensor circuit without a direction. GM's 2023 Corvette Z06 table 23OBDG07 lists only the separate low and high codes P25C6 and P25C7 for this sensor in its EBCM section, plus C0579 and C057A for a second sensor; a generic circuit code does not appear there, and no manufacturer publishes P25C4. GM requires the booster temperature sensors to be fault free before it runs its rotor and ECU over-temperature checks, so a failed sensor removes that protection.
- What you may notice
- Brake system warning in the cluster
- Brake pedal may feel harder if assistance is reduced
- Stored code, often together with chassis codes
- Likely causes
- LikelyTemperature sensor inside the booster unit defective
- PossibleCorroded or loose booster connector
- RareFault in the booster control electronics
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.