What it means
Brake Booster Motor B Phase U-V-W Current High: the control module has detected this fault condition. The electric brake booster generates the braking assist; a motor or sensor fault can reduce or disable power-assisted braking. Safety-relevant.
At a glance
- Usually lights the ABS or stability-control warning light
- The engine or gearbox may go into limp mode
How it works
Brake booster motor B is an electric motor that helps provide power-assisted braking, and its U, V, and W phase circuits carry the drive current. The control module monitors those phase currents; C0592 sets when motor B current is higher than expected, which may result from a binding motor or a short in its phase wiring.
Common causes
Most likely first.
- Brake booster motor B overloaded or binding
- Motor phase wiring short or fault
- Motor or drive circuit fault
- Control module fault
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
How to diagnose it
- Review freeze-frame data and related booster codes to see when high motor B current was detected and whether other electrical faults were present.
- Inspect motor B phase wiring and connectors for pinching, damaged insulation, corrosion, or heat damage.
- Check for signs that motor B or its booster mechanism is binding, following the manufacturer's safety instructions.
- Test the U, V, and W phase circuits for shorts and compare motor B checks with the manufacturer's specifications.
- If the motor and wiring pass, use the manufacturer's diagnostic procedure to check the drive circuit and brake control module.
Common fixes
- Repair a short or damaged connection in motor B phase wiring.
- Correct a binding motor B booster mechanism if it is serviceable.
- Replace motor B if it fails the specified electrical or operating checks.
- Repair or replace the motor drive circuit or control module only after verifying the motor and phase wiring.
Can I keep driving?
Motor B overcurrent can reduce or disable brake assist and may switch off stability functions. Avoid driving if braking feels abnormal or warning lights are on, and arrange prompt repair.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.