Wheel Speed Sensors
An active wheel speed sensor is installed in each wheel hub to give the ABS control module a rotational speed signal from each road wheel. The head of each front wheel speed sensor is positioned close to a magnetic encoder ring incorporated into the inboard seal of the wheel bearing. The head of each rear wheel speed sensor is positioned close to a magnetic encoder ring incorporated into the rear wheel bearing assembly. A fly lead connects each sensor to the vehicle harness.
All of the wheel speed sensors have a signal and a return connection with the ABS control module. When the ignition is ON, the ABS control module supplies a signal feed to the wheel speed sensors and monitors the return signals. Any rotation of the road wheels induces current fluctuations in the return signals which are converted into individual wheel speeds and an overall vehicle speed by the ABS control module. The ABS control module broadcasts the individual wheel speeds and the vehicle speed on the HS CAN powertrain systems bus for use by the other systems.
If the ABS control module detects a wheel speed sensor fault, the 'ABS FAULT' message appears in the IC message center and an amber warning indicator comes on.