The function button for private locking is located in the center display's Function view. Depending on the current status of the lock, Private Locking Unlocked or Private Locking Locked will be displayed.
Private Locking
The trunk lid and rear seat backrests can be locked using the private locking function, e.g. when the vehicle is left at a workshop or with a valet. This function prevents the trunk lid from being opened and locks the rear seat backrests in the upright position.