Was out shopping the other day in my 09, had it parked for about an hour. Got back to the car to go home, put key in and NOTHING - all was dead - no horn, no key fob workings, nothing! On the phone with roadside assistance arranging for help - 5 minutes or so - when all of a sudden the radio and instrument panel went on, WITHOUT the key in! Put the key in, and it started up - like nothing happened! So weird right?!?! Didn't drive it for a few days. I made an appointment for the dealer to check it out one week after it happened but don't know what they will find! Any suggestions? Yes, I usually keep the auto lights, auto wipers and radio with auxiliary satellite radio plugged in and on when car is turned off. By the way, some brake sensor switch has been replaced on this vehicle twice in the last six months and it's starting to have the same symptoms like it's going out again (sputtering/hesitating to take off, etc). First I'll get the ESP light on and then the check engine light goes on. Help anyone?