C05B3 code meaning
Brake Booster Temperature Sensor C Circuit Low
Chassis system Generic code C05xx codes Check engine light
What C05B3 means
C05B3 means the third temperature channel of an electromechanical brake booster has dropped below its usable band. Mitsubishi documents the code for the Outlander PHEV: the DTC index pairs it with the brake unit's own code C18FC-18, EBA temperature sensor 1, and lights the brake system warning lamp plus the MIL after two trips. The value comes from the control electronics inside the electric intelligent brake unit. With the motor switch on, Mitsubishi stores the fault within one second if that reading is at or below −43 °C or at or above 169 °C. The fail-safe column says normal condition, so assist keeps working. Mitsubishi files its second sensor under C0579/C057A. Listed causes are harness, connector and the brake unit itself.
C05B3 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C05B3
- Brake system warning lamp on
- Check engine lamp on after two trips (Mitsubishi)
- Braking assist usually unchanged
Common causes of C05B3
- Most likelyFault in the temperature detection inside the electric brake unit's control module
- PossibleCorroded or loose brake unit connector or damaged harness
- Less likelySupply disturbance during start-up distorting the reading
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake booster temp sensor cElectric brake booster
What each part of C05B3 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B3 | The exact fault in that area. |
What to do next
- Note C05B3 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C05B3
What does C05B3 mean?
C05B3 means "Brake Booster Temperature Sensor C Circuit Low". C05B3 means the third temperature channel of an electromechanical brake booster has dropped below its usable band. It is a generic code, so it means the same on every make.
Is it safe to drive with C05B3?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will C05B3 fail an emissions test?
C05B3 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C05B3 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will C05B3 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.