Normal Operation
WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The active wheel speed sensors generate a square wave signal that is sent to the anti-lock brake system (ABS) module. The wheel speed sensor circuitry connects to the ABS module through 2 wires and a connector at each wheel speed sensor. When the ignition is turned to the RUN position, the ABS module carries out a self-test by sending a reference voltage to all of the wheel speed sensors and their circuitry to determine if they are functional.
Voltage and a ground signal are supplied to the wheel speed sensors from the ABS module.