Wheel Speed Sensor
WARNING: This page is about a different car, the 1997 Acura 3.5RL. However, it is still accessible from the selected car via links, so may be relevant.
Wheel speed sensor consists of a permanent magnet, coil and wheel pulser (trigger wheel). Wheel speed sensors detect wheel rotational speed. As wheel pulser rotates, magnetic field around coil in each wheel speed sensor fluctuates, generating voltage frequency proportional to wheel rotational speed. These pulses are sent to ABS control unit to determine wheel speed.