Anti-lock braking system (ABS) (Opel Vectra B)

The anti-lock braking system prevents the wheels from locking during heavy braking. Thanks to this, the car remains steerable under full braking. The system consists of a hydraulic regulator unit and 4 wheel sensors. The regulator unit contains an electronic control unit (ECU), hydraulic electromagnetic valves and an electrically driven pump. The electromagnetic valves are controlled by the ECU, which receives signals from 4 sensors installed on each wheel of the car, which monitor the rotation speed of each wheel. By comparing these signals, the ECU can determine the speed of the car. By comparing the speed of an individual wheel with the average speed of the car, the control unit determines the state of wheel locking. When the wheel approaches locking, the brake fluid pressure is too high, so the pressure in the caliper is reduced by a signal from the control unit. This continues until the wheel begins to accelerate again. Then the valves close again and the pressure created by the brake pedal begins to act again. However, the pressure value in the brake circuit of this wheel is not higher than the total pressure in the system. During hard braking, ABS operation is repeated on each wheel until force is applied to the pedal or the vehicle stops.

If there is any malfunction in the ABS system, it is switched off. In this case, the ABS control lamp on the instrument panel lights up and the brake system operates in normal mode.