Wheel Speed Sensor
All 4 wheel speed sensors are active (magneto resistive) sensors that operate on the Hall-effect principle to generate a square wave signal proportional to the rotational speed of the wheel. Because these are active sensors, receiving voltage from the ABS module and sending a varying voltage back to the ABS module, they are able to detect much lower rotational speeds than passive (magnetic inductive) sensors. Each wheel speed sensor is connected to the ABS module by 2 circuits. One circuit provides voltage for sensor operation and the other circuit provides sensor input to the ABS module.
The front wheel speed sensors are integrated into the front wheel bearing and wheel hub assembly and are serviced with the bearing and hub assembly.
The rear wheel speed sensors are mounted on the axle flange at the brake dust shield and can be serviced separately.