Anti lock brake system is a safety system which tries to maintain the vehicle steerability, directional stability, and optimum deceleration under severe braking condition on most type of roads surfaces by modulating the brake line pressure to prevent the wheel lock up while monitoring the wheel rotational speed. It consists of three main components: Wheel speed andlide control sensors with an electronic control unit( ECU) and a hydraulic unit. The four wheel speed sensors feed the control unit with variable voltage depending on the wheel speed, and the control unit will set off an alarm that a wheel is about to lock up, then commands the hydraulic unit to manipulate the pressure on the brake caliper at that particular wheel through electric solenoid valves. In the event of a problem, a yellow 'ABS' warning light will light up on the dashboard When performing a visual check on the ABS wiring harness it is advisable to look out for damage around each wheel. Wiring harnesses that have been damaged have to be replaced and not repaired because even a slight change in the resistance results in system failures. In case there is need to disconnect or reconnect the electrical connections make sure the ignition is off. If the warning light of the dashboard is glowing while running the car, then it is a sign that the ABS has some issues and before taking it to the professional, you should check the brake fluid level, ensure the wires are properly connected, check for faulty fuses, and inspect the wiring harness. If the above checks do not address the problem then a qualified technician should override the system. To replace the wheel speed sensor, unbolt the wheel lug nuts, lift the car with the help of a jack, detach the wheel and, perhaps,
Brake Disc or
Brake Shoes in order to get to the sensor. The wheel speed sensor can be easily removed by disconnecting the wiring harness and then undoing the mounting bolt of the wheel speed sensor and extracting it after which the process can be reversed.