Anti-Lock Brake Sensor
NOTE:
Any time an anti-lock brake sensor is removed, thoroughly clean the mounting surfaces. On front anti-lock brake sensors, apply high-temperature 4x4 front axle and wheel bearing grease.
The anti-lock brake system uses four "active" sensors and four sensor indicators to detect the speed of each wheel. The teeth on the sensor indicator rotate past the stationary sensor at wheel speed. As the teeth pass the sensor, a digital input signal is generated. The control module uses the input to compute the speed of each wheel.