Anti-Lock Brake Sensor
WARNING: This page is about a different car, the 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
The anti-lock brake system uses four variable-reluctance sensors to determine vehicle speed. The anti-lock brake sensors operate on magnetic induction principles. As the teeth on the anti-lock brake sensor indicator rotate past the stationary anti-lock brake sensor, a signal frequency that is proportional to vehicle speed is generated and sent to the anti-lock brake control module.