Chassis, generic

C0586 Brake Booster Motor B Phase U-V-W Circuit Range/Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C0586 is set when the B drive stage of the booster motor is electrically connected but behaves implausibly: phase currents that do not match the command, a transistor pair conducting at once, or a bridge driver that fails its start-up self-test. Nobody publishes limits for side B. GM's tests for motor A under C0582 – more than 150 A in a cross-switching test, an idle phase not at 1.65 V – show what such a check looks like. TI's DRV3245Q-Q1, designed for electric brake and brake assist, adds shoot-through prevention and gate-source monitoring for the same purpose. In a dual-winding motor like the Hyundai Mobis one, diagnostics classify each power module as healthy or failed; the failed one is switched off, so the driver may notice a weaker or slower pedal response.

Likely causes

Bridge driver of channel B failing its self-test
Current measurement of channel B drifting, currents no longer match the command
Control unit software issue, resolved by update where available

Symptoms

  • Brake warning or service message
  • Pedal response weaker or slower than usual

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–3,000
Time0.5–4 h

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

Parts involved

brake booster motor b

Related codes

C0583C0584C0585C0582

References: ti.com, patents.google.com, gsi.ext.gm.com.