Wheel Speed Sensor (WSS) and Tone Wheel

DESCRIPTION













One Wheel Speed Sensor (WSS) and one tone wheel are located at each front and rear wheel. Each front wheel speed sensor is attached to a boss in the steering knuckle. Each rear wheel speed sensor on All-Wheel-Drive (rear disc brake) applications is mounted to the rear axle flange and disc brake adapter. Each rear wheel speed sensor on Front-Wheel-Drive (rear drum brake) applications is mounted to the rear axle flange).

Each front tone wheel on all models is part of the driveshaft outboard constant velocity joint. Each rear tone wheel on All-Wheel-Drive (rear disc brake) models is also part of the outboard constant velocity joint. Each rear tone wheel on Front-Wheel-Drive models is an integral part of the rear wheel hub and bearing.

OPERATION
Each wheel speed sensor sends a small AC signal to the CAB. This signal is generated by magnetic induction created when a toothed sensor ring (tone wheel) passes the stationary magnetic wheel speed sensor. The CAB converts the AC signal into a digital signal. If a wheel locking tendency is detected by the CAB, it will then modulate hydraulic pressure via the HCU to prevent the wheel(s) from locking.

Correct ABS operation is dependent on accurate wheel speed signals. The vehicle's tires and wheels all must be the same size and type to generate accurate signals. Variations in tire and wheel size can produce inaccurate wheel speed signals.

Improper speed sensor-to-tone wheel clearance can cause erratic speed sensor signals. The speed sensor air gap is not adjustable, but should be checked when applicable. Wheel speed sensor-to-tone wheel clearance specifications can be found in Specifications.