Saab 9000's TCS system was one of the earliest Traction Control systems applied to road cars. To Saab 9000 and other front-wheel drive cars, hard acceleration used to cause trouble to the driving wheels. Hard acceleration always causes weight transfer which lightens the front end. This reduces the traction of front wheels, thus causing wheel spin. When wheel spin occurs, the friction between wheels and ground drops considerably so that it takes longer to launch. Moreover, wheel spin also introduces instability.
Besides, the combination of a powerful engine and 2WD always result in wheel spin. This also calls for the need of Traction Control.
Like other subsequent Traction Controls, Saab's TCS prevents wheel spin by lowering engine output or even applying brakes to the spinning wheels. All these actions are tightly monitored by the microprocessor. Based on essentially the same hardware as ABS, in collaboration with engine management system, TCS adds little cost.