Anti-lock braking system (ABS) (BMW 3 Series E46)

Operating principle

The ABS system increases the active safety of the car by preventing the wheels from locking when braking. After all, wheel locking is extremely dangerous, since the front wheels become uncontrollable, and the skidding rear wheels can cause the car to skid and be thrown onto the other side of the road.

The ABS system allows in any specific conditions (when driving straight, on a turn, on an asphalt icy or sea road, etc.) reduce the braking distance to a minimum. In principle, with each braking, ABS should solve two problems, ensuring trajectory stability, reliable controllability and maneuverability of the car when driving on roads with different types of surfaces (asphalt, concrete) and in different states (icy, covered with mud, snow, water).

Features of driving a car with ABS

The system is automatically activated only when the speed reaches about 10 km/h. When it falls below 6 km/h, ABS is switched off, so theoretically the wheels can lock at the very last stage of braking, but in practice this is no longer of fundamental importance.

The benefits of ABS are most evident in situations where you have to apply maximum force to the brake pedal. Since the front wheels of the car remain steerable, you can safely drive around the obstacle.

ABS carries out the regulation process in a fraction of a second. The pulsation of the pedal under the foot means that the braking is under the control of ABS, in other words, that the driver is driving in the limit mode. In addition, the crackling caused by the ABS operation process reminds the driver of the need to adjust the speed to the actual driving conditions that have changed due to the reduction (for example, due to icy conditions) coefficient of friction (or clutches) between the tires and the road.



On roads with a loose layer (for example, gravel or snow) over a base with good grip properties, the braking distance may be longer than when the wheels are locked. This also applies to driving with anti-skid chains. Much more important, however, is the gain in trajectory stability and control of the car.

Important information for your safety

ABS does not cancel the laws of physics. The system cannot prevent the consequences of braking at insufficient distance from the vehicle in front, cornering at an unacceptably high speed or when there is a risk of aquaplaning. These consequences still remain on the driver's conscience. The presence of ABS, which provides increased safety potential, should not provoke you to an excessively risky driving style.

Driving on different tires, for example after installing a spare tire (in combination with the other three wheels, which are fitted with winter tyres) may limit the functionality of the ABS. Therefore, the removed wheel should be reinstalled as soon as possible.

Do not make any changes to the system.

Work on the system should only be carried out by specialists.

Anti-lock Braking System (ABS) / Cornering Brake Control (CBC)

The SBC system is an improved version of ABS. Under braking conditions on turns with high lateral acceleration, as well as when braking while changing lanes, the system improves driving stability and control.

In case of malfunction

The malfunction signal is the ABS warning light coming on. In this case, the brake system continues to operate normally, as on cars without ABS. Refer to Section Troubleshooting.





If the lamp lights up together with the ABS and ASC+T/DSC* control lamps, this indicates that the entire ABS, CBC and ASC+T/DSC control system has failed. You can continue driving, taking the necessary precautions, as the car may become unstable and go out of your control.

Please refer to Section Troubleshooting and go to a BMW service station as soon as possible to have the system checked.