Chassis, generic

C058B Brake Booster Motor B Position Sensor Circuit/Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C058B reports an open circuit at the position sensor of booster motor B. Such a second sensor exists where the booster has a second motor or winding system with its own commutation, or where the rotor angle is measured twice for safety. Stellantis shows that the eBooster of the Jeep Wagoneer has a motor B position channel, since its parts bulletin names C058E (range/performance) for it; C058B itself is not published by any maker. Kollmorgen's early patent on redundant windings gives every winding set its own group of Hall sensors, so losing one group only affects that set. An open line is detected as in Hitachi's resolver circuit: the bias signal no longer arrives and the input floats to its pull-up level. The module then drops channel B and runs on A or with reduced assist.

Likely causes

Broken signal or supply wire of position sensor B
Loose or corroded contact in the sensor B connector
Failed sensor element B inside the booster

Symptoms

  • Brake system warning with service message
  • Possibly reduced assist or limited assistance functions

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–2,800
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

booster motor b pos sensorsensor wiring

Related codes

C058CC058DC058EC0587

References: static.nhtsa.gov, patents.google.com, patents.google.com.