The front wheel speed sensors consist of a variable reluctance sensor. The sensor and toothed ring are part of the sealed hub and bearing assembly. This allows for improved environmental protection and easier assembly. As teeth pass by the sensor, an AC voltage with a frequency proportional to the speed of the wheel is generated. The sensor is not repairable, nor is the air gap adjustable. The sensor and toothed ring cannot be serviced separately from the hub and bearing assembly. If a front wheel speed sensor fails, the entire integral hub bearing/sensor assembly must be replaced.
The rear wheel speed sensors operate in the same manner as the front wheel speed sensors. However, the rear wheel speed sensor and toothed ring are contained within the dust cap of the integral rear wheel bearing. This allows for improved environmental protection and easier assembly. Like the front sensors, the rear sensor and toothed ring are not repairable and no provision for air gap adjustment exists. If a rear wheel speed sensor fails, the entire integral hub bearing/sensor assembly must be replaced.
Between each wheel speed sensor and the main wiring harness is a jumper harness made up of highly flexible twisted pair wiring. This wiring is there because the main harness must connect to the suspension of the vehicle. The wiring in this area is subjected to the same motion as a spring or shock absorber. Consequently, any repair to this section of wiring will result in stiffening and therefore, eventual failure due to wire fatigue. Service is by replacement only. Use care when working around the wheel speed sensor and the jumper harness.
Removal & Installation
The wheel speed sensors, front and rear, are built into the non-serviceable wheel bearing/hub assembly. If a wheel speed sensor is proved to be defective, the entire wheel bearing/hub assembly must be replaced. For wheel bearing/hub assembly replacement, please see the procedures in Section 8.