C05B4Brake Booster Temperature Sensor C Circuit High
- Generic OBD-II code · Chassis
- Turns on the check-engine light
- How the car detects it
- C05B4 is the upper-limit counterpart: temperature channel C of the electric booster reports a value above its permitted maximum. In Mitsubishi's Outlander PHEV index it stands next to C18FC-19, again EBA temperature sensor 1, with the same lamp logic – brake system warning lamp and MIL after the second trip. Mitsubishi's description page for this subcode repeats the criteria of C05B3 word for word (−43 °C or colder, 169 °C or hotter, detected within one second), so the split into low and high lies in the electrical evaluation, not in the published temperatures. Whether a high signal stands for heat or cold depends on how the thermistor is wired in its divider. Because the sensor sits on the control board, a persistent fault usually means replacing the brake unit.
- What you may notice
- Brake system warning lamp on
- MIL on after the second trip (Mitsubishi)
- Code returns immediately after clearing if the unit is defective
- Likely causes
- LikelyTemperature circuit on the brake unit's control board defective
- PossiblePoor contact at the brake unit connector or chafed wiring
- RareGenuinely excessive electronics temperature after heavy booster use
- 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.