FUNCTION OF COMPONENTS Component | Function Front Speed Sensor | Detects the wheel speed of each of the left and right front wheels. Rear Speed Sensor | Detects the average wheel speed of the left and right rear wheels. ANTILOCK Warning Light | Lights up to alert the driver when trouble has occured in the Anti-lock Brake System. A.B.S. Actuator | Controls the brake fluid pressure to each disc brake cylinder through signals from the computer. Anti-lock Brake System Computer | From the wheel speed signals from each sensor, it calculates acceleration, deceleration and slip values and sends signals to the actuator to control brake fluid pressure. LOCATION OF SYSTEM PARTS Rear Speed Sensor (W58) Anti-lock Brake System Computer ANTILOCK Warning Light A.B.S. Actuator Rear Speed Sensor (A340E, R154) Neutral Start Switch (A340E) Front Speed Sensor BR31R1