Source: DSC MX-5
The Dynamic Stability Control system (DSC) automatically takes control of the vehicle when skidding is detected. The system guards against skidding by optimally controlling engine output and the braking force applied to each wheel through the combined control of the 4-wheel antilock braking system (ABS) and the Traction Control System (TCS). This helps the vehicle maintain stability even in situations such as when cornering on slippery roads or when steering suddenly to avoid hazards.
Sensors in the vehicle provide speed, steering angle, lateral-G and yaw rate data for both systems, and the performance parameters are effected by the Sport mode switch and the LSD in the Abarths.
For example, if the car understeers and tends towards the outside of a corner, engine output is controlled and braking is applied primarily to the inner front wheel according to the degree of the tendency. As a result, a yaw moment is formed towards the inner side of the vehicle and the understeer tendency is suppressed.
Conversely, if the vehicle oversteers and tends toward the inside of a curve, braking is applied primarily to the outer front wheel according to the degree of the tendency. As a result, a yaw moment is formed towards the outer side of the vehicle and the oversteer tendency is suppressed.
The two systems work in harmony, and can normally be controlled together with quick presses of the DSC button ⇓ :
DSC operation is possible at speeds greater than 12 mph (20 km/h), and is normally ON each time the vehicle is started. TCS is normally in standby mode, but it will activate if, for instance, you attempt to free the vehicle when it is stuck, or drive it out of freshly fallen snow. Depressing the accelerator will not increase engine power and freeing the vehicle may be difficult. When this happens, either deactivate both TCS/DSC (short press of the switch), or with a long press (10 seconds+), you can deactivate TCS independently of DSC.
Note that deactivation of DSC is a misnomer though, since the steering safety system remains in readiness mode, and will re-engage itself, although under more extreme parameters.
Reset DSC: Hold DSC/TCS button 10 seconds+