Antilock Brakes / Traction Control Systems: Description and Operation

Location Of Main Components:

The illustration shows an earlier configuration with the hydraulic modulator and control module mounted at the rear. The hydraulic modulator is installed in the engine compartment and the control module in the passenger compartment on models from 1988 on.

The ABS system consists of the following main components: hydraulic modulator, sensors, control module, wiring and a warning lamp on the combined instrument which lights if the system becomes inoperative.

Vehicles equipped with ABS have an axle-split braking system. The rear piston in the master cylinder serves the front axle and the front cylinder the rear axle.

ABS ensures that directional stability and steering control are maintained, and the braking distance minimized, when the brakes are applied. This is achieved by a combination of precision hydraulics and digital technology.

The system is designed to sense the degree of friction between the road surface and each of the tires, and the control module automatically operates the hydraulic system so as to maintain the correct pressure in the braking circuits at all times. If a wheel is about to lock, the supply pressure to that caliper is reduced temporarily.

A warning lamp on the combined instrument lights if the ABS system is inoperative. Note: The normal braking function is available at all times.