Service manual

Group 59 Anti-Lock Brake System (Bendix) Design and Function
Tooth Wheel
The tooth wheel is an alloy ring that resembles a gear. It
normally has 100 teeth cut into its surface. The purpose
of the teeth are to cause a pulsating current flow in the
sensor circuit. As each tooth passes near the sensor, it
causes a small current to flow in the sensor. When the
gap between two teeth is in front of the sensor, the cur-
rent flow stops.
As the tooth wheel rotates, the starting and stopping of
the current flow is registered by the ECU as pulses. The
greater the speed of the tooth wheel past the sensor, the
more pulses are registered per second, which is a direct
indication of wheel speed.
The tooth wheel is manufactured either as a ring that is
pressed onto the wheel hub, or is machined as an inte-
gral part of the hub itself.
W5000530
Tooth wheel
13