Dynamic Control System

For 2002, the 3 Series' Dynamic Control System (DSC) has been refined. DSC has been standard since mid-‘99 and it was upgraded in September 2000 with the addition of Dynamic Brake Control (DBC). 

A function called Automatic Differential Brake, which via a brief push of the DSC button on the console de-activates the system's engine intervention but leaves the brake intervention functional, was already present; this "softens" the traction-control effect of DSC and is useful on certain very slippery surfaces, such as gravel or packed snow. In this mode, when the drive wheels begin to slip, individual wheel brakes react to control the slip but the usual reduction of engine power does not occur. 

New for 2002 is a phase-in of engine intervention with increasing vehicle speed, adding stability at higher speeds while leaving the moderated traction-control effect at low speeds. BMW calls this Dynamic Traction Control. As before, pressing the DSC button for a longer period (2 seconds) completely de-activates all DSC functions except antilock braking.

DSC is an all-encompassing system and includes the following functions:

• All-Season Traction (AST) control intervenes via engine power and/or brakes to optimize traction at all vehicle speeds. BMW first made this feature standard in 1997, and it has always been part of the overall DSC system.
• Automatic Differential Brake (ADB) and Dynamic Traction Control (DTC).
• Antilock braking hinders wheel lockup or skidding to help the driver control the vehicle under hard braking.
• Electronic Brake Proportioning. Anytime the brakes are applied, there is some degree of wheel slip. The slip indicates the degree of braking at any given wheel. EBP continually monitors slip and distributes braking force to the wheels for optimal braking effect and relatively even brake and tire wear.
• Dynamic Brake Control. In hard or emergency braking, DBC intervenes to assist the driver in achieving the shortest possible stopping distance. 
• Stability enhancement. In avoidance maneuvers or hard cornering, DSC recognizes when the vehicle departs from its normal cornering path and intervenes via the wheel brakes and engine power to help keep it on course.

The three all-wheel-drive models come with DSC-X, the AWD version of Dynamic Stability Control. In addition to traction control via the four driving wheels and all the functions listed above, for 2002 DSC-X adds Hill Descent Control, a function used in BMW's X5 Sports Activity Vehicle.

Hill Descent Control helps the driver maintain speed and stability on steep downhill runs. There is a button on the console to activate it. HDC gently applies the brakes to help keep the speed to a brisk walking pace.