Mercedes has announced that they are recalling certain models of the 2009 S Class, W221 vehicles. They stated it was due to part number label of the door locks it could be that the front and rear passenger side door locks were interchanged during production. The exchange of a front and rear passenger side door lock would result in a passenger side door that cannot be opened by merely pulling on the interior handle and a rear door lock that can be opened with a simple pull of the interior door handle even if locked.