Brake-by-wire
A braking-system family in which driver demand is sensed electronically and coordinated with controlled brake actuation.
Key facts
Overview
Brake-by-wire is a vehicle-system function, not a single component. Diagnosis must separate driver-demand sensing, control logic, network communication, electrical supply and the physical brake actuator/hydraulic path.
Wheel-speed, brake-demand/pressure, steering-angle and yaw/acceleration information can participate in ABS/ESC and brake-force coordination depending on the vehicle implementation.
Exact pins, thresholds, bleed procedures, calibrations and actuator tests depend on vehicle, model year, market and controller version and require the applicable OEM service source.
Operating principle
- Capture driver brake demand and verify that the controller receives a plausible request.
- Compare wheel speeds, steering angle and yaw/acceleration context where supported.
- Compare commanded braking or pressure/deceleration request with actual hydraulic/electric actuator response.
- Separate ABS/ESC intervention or regenerative-braking coordination from the base brake-demand path.
Main components
- Brake-pedal or driver-demand sensors.
- Brake/vehicle-dynamics controller and gateway/network path.
- Wheel-speed and vehicle-motion sensors.
- Pressure/actuator feedback, hydraulic modulator or electromechanical actuator depending on the application.
- Power supply, grounds, fuses and communication wiring.
Diagnostic and service approach
- Preserve DTCs, freeze-frame/event data and 12-V system condition before clearing codes.
- Compare pedal/request input with commanded brake output and actual physical response.
- Check wheel-speed plausibility and network message continuity before condemning a controller.
- Measure power and ground voltage drop under load and separate electrical command from hydraulic/mechanical brake faults.
- Perform calibration, bleeding or actuator procedures only with the exact vehicle OEM service procedure.
Variant and safety boundary
- The same marketing term can use different hydraulic, electrohydraulic or electromechanical hardware across platforms.
- Do not publish or reuse numeric bleed pressures, actuator travels or calibration thresholds across unmatched variants.
Open the standard page for broader relationships, sources and interactive navigation. Full technical page →