We have a '18 Allroad. Had a 4.2 Alload before. Love most things about the new Allroad. Occasionally when backing up a grinding noise and braking occurs - it does not create a code. No PreSense triangle appears and no warning sound. Has happened 2 to 4 times a month since new in Feb '18. PreSense has braked the car like it was reacting to an imminent collision four times. Twice on an outside curve at 55 mph with an approaching car. Once at 45 mph with absolutely nothing nearby - driving, parked, birds, deer, dogs, falling leaves, etc...nothing. Once pulling into very open area of parallel parking with car parked several spaces ahead - 40 ft plus ! NONE of these events have created a code. The dealership initially told me no customers at Hoffman, New London, CT had experienced anything like that. A customer in service next to me said that she had as well. No one spoke to her about her experience. That was in May '18. Since then the Service Mgr and all of the Service Reps have had similar experiences, yet there is nothing they can do because there is no code or fault. Have spend countless hours with Customer Service and they have been equally in denial. The braking issue many years ago was trumped up. PreSense is full of bugs and no is being honest about that. I asked if the cars software could be reloaded with updated software and was told that option does not exist.