I accidentally managed to turn-off my 2011 CTS AWD yesterday morning during a light snow fall. Was using manu-matic to stay in lowest gear and got a message that I had activated sport mode and that AWD was turned off. Owners manual referred to sport mode (delayed up-shifts) but no comment about turning off AWD. During lunch break, returned to car and defaults had turned AWD back on. Lesson learned-RWD is not as effective on slippery roads, huh!?