Since yesterday I am proud owner of my SD4`s and have already a question about it. And that is, when I start the engine my PDC is not switched on. Only if I insert the reverse gear my PDC remains on (front and rear) until I reach the 16 km/h speed or until I switch off manually on the dashboard. According to instructions, however, should the PDC also activate as soon as I insert a forward gear and am under 16 km/h fast or is that not right? Yesterday almost already where I was thinking now he has to pee and another little question. The small wheel next to the button for the automatic tailgate under the steering wheel left. What is the good for ?