ABS

ABS or Anti-Lock Braking System is a system to prevent the wheels locking up when you mash the brakes, resulting in a safer, more controlled deceleration.

Overview

The ABS system is a closed-loop system comprised off an ECU, four sensors and a pump. By measuring the speed of each wheel, the ABS can detect when any one likely to lock up under braking. It then "pulses" the ABS pump, which is directly connected to the brake master cylinder, to apply the brakes in "ripples" rather than a constant force. This allows the wheels to maintain their turning, thus preserving a modicum of steering ability in times of danger.

The ABS works by reading pulses from toothed "rings" that slot around each front and rear wheel hub. For this reason, ABS wheel hubs are different to standard wheel hubs.

The condition of the ABS system is shown by a warning light in the instrument cluster. With ABS fitted, the light should turn on with the ignition, but switch off soon after. A light that refuses to turn off is a sign of a problem.