What is DTC in a BMW?

Dynamic Traction Control (DTC) allows more wheel slip and thus a more dynamic driving style with higher wheel traction and DSC controlling stability. A small amount of spin on the drive wheels improves traction when pulling off from a standstill in snow or on loose terrain. read more

Officially, BMW state that DTC is for low traction situations, e.g. mud, gravel or ice. However, it's pretty clear that it's also designed to allow for a more sporting drive. Motoring journalists often describe it as emulating an electronic limited slip diff. read more

DTC button controls the 3 BMW’s traction control settings. I’m going to add a little which may not be covered by Gene’s answer. There are 3 settings: DSC (Dynamic Stability Control) DTC (Dynamic Traction Control) Off; DSC is for everyday driving. read more