Wheel Speed Sensor Tone Rings
WARNING: This page is about a different car, the 2016 Ford Transit-350 HD, 2016 Ford Transit-350, 2016 Ford Transit-250, and 2016 Ford Transit-150. However, it is still accessible from the selected car via links, so may be relevant.
The wheel speed sensor tone rings are magnetized, toothed rings used to create a Hall-effect switch when combined with the wheel speed sensor. The front wheel speed sensor tone rings are integrated into the front wheel bearing and are serviced with the front wheel bearing. The rear wheel speed sensor tone rings are pressed onto the rear wheel axle shaft and are serviced separately from the axle shaft.