TL* THE CONTACT OWNS A 2008 TOYOTA YARIS. WHILE PARKED WITH THE ENGINE SHUT OFF AND THE KEY NOT IN THE IGNITION, THE VEHICLE SUDDENLY ROLLED BACKWARD WHILE TWO CHILDREN WERE SEATED IN THE REAR SEAT. THE VEHICLE CAME TO A STOP WHEN IT CRASHED INTO A TREE. NONE OF THE CHILDREN WERE REPORTED AS INJURED. THE VEHICLE WAS TAKEN TO THE DEALER FOR DIAGNOSTIC TESTING. THE TECHNICIAN WAS UNABLE TO DIAGNOSE A FAILURE. THE VEHICLE WAS NOT REPAIRED. THE APPROXIMATE FAILURE MILEAGE WAS 75,000.