ABS prevents the wheels from locking up under braking.

The anti-lock brake system (ABS) is an important part of the car's active safety system. However, the ABS will not necessarily guarantee shorter stopping distances in all conditions. For instance, on loose gravel or fresh snow on top of an icy surface (conditions which anyway require extreme care and reduced speed), the stopping distance with ABS may even be slightly longer.

How the ABS works

The system runs an automatic self-check when the car reaches a road speed of about 6 km/h. This may be accompanied by a noise from the ABS pump.

If one of the wheels is turning too slowly in relation to the road speed, and is close to locking up, the system will reduce the pressure in the brake line to this wheel. The driver is made aware of this control process by a pulsating of the brake pedal and accompanying noise. This is a deliberate warning to the driver that one or more of the wheels is tending to lock up and the ABS control function has intervened. In this situation it is important to keep the brake pedal fully depressed so the ABS can regulate the brake application - do not “pump” the brake pedal.

WARNING
The grip provided by ABS is still subject to the physical limits of adhesion. Always bear this in mind, especially on wet or slippery roads. If you notice that the ABS is working (to counteract locked wheels under braking), you should reduce speed immediately to suit the road and traffic conditions. Do not let the extra safety provided tempt you into taking any risks when driving – this can cause accidents.

Note
If a malfunction should occur in the ABS, this is indicated by a warning lamp.