The antilock braking system (ABS) helps your car stop efficiently when you jam the brake pedal and steer simultaneously. This German technology adopted from airplanes prevents your car from skidding or drifting on a muddy or slippery surface.
The ABS comes with three major components:
The wheel speed sensor, which is present at a wheel, sends the signal if the wheel is locked, or anti-locked (moving).
The valve, which controls the flow of brake oil, which then controls the brake pads.
The ECU is the brain of the system, which receives signal from the wheel speed sensors and actuates the ABS modulator to control the valve on/off.
How it works:
When your going on a road in monsoon, and you hit the brakes on the wet road, your brakes work but the car tends to skid a little distance before stopping. This may cause serious accident or send you skidding into the side of the road. In an ABS equipped vehicle, when you hit the brakes, the brake pads jam the brake disc, which locks your wheel. In this scenario, the wheel speed sensor detects the locked wheels and sends signal to the ECU. The ECU is a smart computer that detects that the car is still moving while the wheels locked. Here, it controls the valve to release the oil and reduce the pressure on the brake pads, thereby unlocking (or anti-locking) the wheels. Moreover, when the wheels start moving again, the ECU commands the valve to lock wheels again. It does so around 15 times in a second, which brings to halt your vehicle without sending it into a skid. You may feel the pulsation when you step on your brake pedal in an emergency braking condition.