The anti-lock brake system aims at keeping the vehicle steerable, on the intended path and achieves the best level of deceleration by checking the wheel rotational speed and regulating the brake pressure in order not to lock the wheels. It consists of three main components: wheel speed sensors, electronic control unit, hydraulic unit-all in one housing. Every of the four wheels has a speed sensor, which transmits to the control unit a variable voltage signal, and depending on whether the wheel is about to lock up, the hydraulic unit will vary the brake pressure through solenoid valves by an electric signal. In the event of a problem, an 'ABS' light turns on the instrument panel, and checking the ABS wiring harness around each wheel area will reveal signs of rubbing or harm. Several things that are tested when diagnosing a dashboard warning light include the brake fluid, security of the wiring connection, the fuses, and the wiring harnesses. If these detections do not solve the problem, then it requires expert detection and rectification by a skilled technician. For wheel speed sensor replacement, switch of the ignition and loosen the lug nuts of the wheel and raise the car until it is stabilized and the wheel is taken off. To remove the sensor, the wiring harness should be taken off the brackets, the electrical connection also to be disconnected and the mounting bolt should also be unscrewed. Installation is done in the reverse sequence making sure that the sensor and the lug nuts are tight before lowering the vehicle.