OBD-II code · Chassis

C058B Brake Booster Motor B Position Sensor Circuit/Open

Brake Booster Motor B Position Sensor Circuit/Open: the circuit is open. The electric brake booster generates the braking assist; a motor or sensor fault can reduce or disable power-assisted braking. Safety-relevant.

Is it safe to drive with C058B?

The car may go into limp mode (reduced power). Get it diagnosed before a long trip.

Common causes

  • Most likelySignal wire open
  • Less likelyPin pushed back out of connector body
  • Less likelyCracked solder joint inside the module or sensor

Symptoms

  • ABS warning light on
  • ESC/stability control deactivated
  • Possible reduced brake assist
  • Speedometer may behave erratically

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
1–5 h
Emissions test
Usually unaffected
Parts involved
Booster Motor B Pos Sensor

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.