Wheel speed sensor

From ArticleWorld

A Wheel speed sensor is usually a pair of connecting gears that are used to determine the speed of a rotating wheel. Each wheel on a vehicle has its own speed sensor, which sends a signal to the control module. Proper ABS operations rely on accurate speed signals. The vehicle must have wheels and tires that are the same size and type to produce accurate signals. If there is a difference in wheel and tire sizes, inaccurate wheel speed signals will be generated .


It is critical that the wheel speed sensor(s) are properly installed to ensure safe system operation. The cables must be installed, routed and clipped correctly. Wheel speed sensors that are not installed properly may cause contact with moving parts or stretched sensor cables. This can cause ABS components to failure and leave an open circuit. Some manufacturers use a magnetic type of sensor that detects the wheel speed rotation. It consists of a coil and a permanent magnet, with a pulser (tone ring) attached to the rotating parts. When rotation occurs, this generates voltage, which is sent to the ABS control unit.


  1. Elevate the wheel making sure the vehicle is safely supported.
  2. Remove the wheel.
  3. Unbolt the sensor from the axle or steering knuckle.
  4. The rotor of the wheel speed sensor is fastened to the inside of the wheel hub. To remove the rotor, the hub needs to be pressed out of the wheel bearing.
  5. On most rear wheels, the wheel speed sensor is pressed into the brake rotor. Remove it by pulling the wheel bearing and brake rotor.
  6. Insert a punch or drift pin through the bolt holes and lightly tap the speed sensor rotor out at each hole, similar to removing an inner bearing race.


  1. During installation, use an appropriate sleeve to evenly drive the sensor rotor into the brake rotor.
  2. Install the cover ring, the distance from the splash shield to cover ring the should be 0.375 inch (9.5mm).
  3. When installing the sensor, use a dry (graphite) lubricant on the sensors sides, and tighten the bolt to 7 ft. lbs. (10 Nm).