Brake-pad wear sensor
Signals when a monitored pad reaches its sensing stage.
Clipped into selected brake pads according to axle design.
Wear changes the electrical circuit; vehicle software interprets that signal with other information.
A sacrificial messenger embedded near the wear limit.
A wear warning can reflect worn pads, a damaged lead or an incorrect connection.
Pads and discs are measured wear items. Driving, environment and regenerative braking change wear; use the actual inspection limits.
Ordinary friction service differs greatly from carbon-ceramic replacement or hydraulic-controller work; obtain a vehicle-specific quote.
A BMW wear sensor does not directly measure every pad on every wheel.
BMW models with hydraulic friction brakes; performance equipment and parking-brake design vary.