DTC

[minimatan]

My E63 645Ci has a DTC button.

I know that a long press turns everything off, which is great for confident drivers.

What does the single press setting do?

[quavey]

It engages what I think its called Direct Traction. Its a special mode designed to help in wintery conditions, I believe it attempts to emulate a LSD. It does help, my dad has an E65 with the option. In one year of bad snow it got stuck at a steep hill on the way up to my parents house, engaged DTC and it just made it with some encouragement.

[Pferdestarke]

Default - belt and braces

Single press - Dynamic Traction Control activated - allows more slip but still has your best interests at heart

Long press - you're on your own, son!

Turn it off and learn the car gradually.