See also:

Switching on/off manually
Switching on/off manually Press the button. ...

Deactivating HDC
Press the button again and the LED goes out. HDC is automatically deactivated above approx. 37 mph/60 km/h. ...

Switch off the engine during longer stops
Switch off the engine during longer stops, e.g., at traffic lights, railroad crossings or in traffic congestion. Fuel savings are achieved after the vehicle is switched off for only approx. 4 s ...