Why Would I Need New Sensors? Your BMW has eight brake pads, but only 3 of them are actually monitored for wear (the inner driver's/passengers side front pad and inner passenger rear pad). When a pad has down to below 2mm or remaining frictional material, the rotor will chew through a small plastic bump on the sensor which slices the wire in half and causes your car to show a warning sign on your dash. This is usually warning you that you will need new pads soon. However, once a sensor has been used and a warning has shown, the sensor is destroyed and must be replaced with a new one.
Application Guide
