4 wheel speed sensors

The wheel speed sensors measures the individual wheel speeds. The wheel speed sensors have no detection for the direction of rotation of the wheels.

Fig 1: Identifying Wheel Speed Sensors

Courtesy of BMW OF NORTH AMERICA, INC.

The sensor element and the evaluation electronics are housed separately within the sensor housing. This arrangement ensures advantages with regard to temperature characteristics of the sensor. The wheel speed sensor consists of the sensor itself and evaluation electronics. The permanent magnet in the wheel speed sensor creates a magnetic field. The field lines of the magnetic field run at a right angle to the sensor layer on the sensor element. The deflection of the field lines by the increment wheel causes changes in resistance in the thin ferromagnetic layer of the sensor element.