All wheel drive disengages while driving. It has disengaged several times while driving up a steep hill in the rain resulting in loss of control of vehicle. First time car skidded into a ditch. Warning on dash said return vehicle to dealer. Vehicle has been returned 3 times. They blame the problem on a defect in the emission control system which turns off the AWD system when a leak in the vapor control system is detected. Dealer first replaced the fuel filler cap. That worked for a couple of weeks, then something under the hood which worked a few days. Now the car is scheduled for a gasket on the fuel tank to be replaced for $1,500! I am all for controlling emissions to the environment, but it should not be at the cost of safety. A fix is needed to separate the AWD from the emission control system. SAFETY FIRST!