C05BE code meaning
Brake Booster Motor B Position Sensor Supply Circuit High
What C05BE means
C05BE is stored when the 5 V feed of motor B's position sensor exceeds its upper limit. No manufacturer documents it publicly. Two mechanisms are typical: the supply line has contacted a wire carrying battery voltage, or the reference ground of the sensor side has lifted, which makes every voltage measured against it look too high. Denso's patent illustrates the ground effect for a sensor read through a pull-down: a broken ground drives the signal above 4.7 V. In Hitachi Astemo's cross-check a rising ground pulls both references down while the monitor values stay put, which separates a ground fault from a true overvoltage. TI's tracker cuts its output path when shorted to battery. The booster then drops channel B and runs with motor A or reduced assist.
C05BE at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C05BE
- Brake warning lamp and assist warning
- Possibly further sensor codes if a shared ground is affected
Common causes of C05BE
- Most likelyMotor B sensor supply shorted to a battery-voltage wire
- PossibleOpen or high-resistance sensor ground raising the measured voltage
- Less likelySecond sensor supply regulator out of regulation
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Booster motor b pos sensor supplyElectric brake booster
What each part of C05BE means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| BE | The exact fault in that area. |
What to do next
- Note C05BE 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 C05BE
What does C05BE mean?
C05BE means "Brake Booster Motor B Position Sensor Supply Circuit High". C05BE is stored when the 5 V feed of motor B's position sensor exceeds its upper limit. It is a generic code, so it means the same on every make.
Is it safe to drive with C05BE?
Drive gently and only to a workshop. With C05BE the car can go into limp mode (reduced power) to protect itself.
Will C05BE fail an emissions test?
C05BE 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 C05BE to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will C05BE clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.