In present-day vehicles or motor vehicles an increasing number of electronic access authorization systems are provided, where the access authorization query is initiated via a remote control.  In the simplest case this access authorization system consists of one or several electronically controllable locks, a controlling means and at least one corresponding electronic key, namely the remote control. 
Modern and future access authorization systems or access arrangements in motor vehicles use electronic security systems, for example making use of transponder technology.  Before the opening or starting of the motor vehicle, a wireless data communication first occurs for this purpose between a transceiver disposed in the motor vehicle and a transponder disposed for example in a key or a key fob of the user of the motor vehicle, where encoded data are exchanged, which ensure a valid access authorization, for example by the motor vehicle owner.  One such access authorization system is for example the PASE system developed and sold by the company Siemens VDO, where PASE stands for “Passive Access Start and Entry”.  Here, an access authorization query is initiated for example by the operating of a door handle or merely by the approaching of the motor vehicle.  Since it is not necessary to perform an active operating of a mechanical or electronic key, this type of access authorization is also referred to as passive access authorization query, the corresponding locking systems as passive electronic access authorization systems. 
Occasionally, there is a requirement to retrofit exactly such a passive access authorization system to an existing keyless electronic access authorization system, which does not incorporate a passive access authorization system like the previously mentioned PASE system.  In the case of known systems, in order to retrofit a passive access authorization system a transmitter must be provided on the vehicle side, especially in at least one vehicle door, said transmitter cyclically searching for the electronic key for the passive access authorization system (PASE key).  Furthermore, a corresponding receiver must be disposed on the vehicle side, said receiver being electrically coupled to the central locking of the existing system and sending a corresponding control signal to the central locking, to which it is electronically coupled, after a positive evaluation of the data communication with the PASE key.  Such a retrofittable passive access authorization system is known for example from DE 10 2004 039 835 B3. 
The cited document contains a description of how a vehicle user may obtain access to the vehicle retrofitted with a passive access authorization system.  However, the aspect as to what happens if the vehicle user leaves the vehicle, for example after depositing the vehicle, is not highlighted here.  On the one hand, it might happen that an electronic key for the passive access is left behind in the vehicle, while a signal to lock the vehicle is given by means of a second key due to the actuation of a locking button.  It is also conceivable that a locking of the vehicle is performed by a different mechanism. 
With conventional passive access authorization systems, a special locking signal substantially limited to the interior or a deactivation signal is sent for the deactivation of such electronic keys left behind in the vehicle in order to lock or deactivate the electronic keys remaining in the vehicle at least for a specific time.  With a retrofitted passive access authorization system, as already hinted at briefly above, the retrofitted transmission unit on the vehicle side for the cyclical transmission of query signals to the electronic key is provided especially in a vehicle door.  Due to this it is therefore difficult to transmit a locking signal substantially limited to the interior without unintentionally locking or deactivating electronic keys located outside the vehicle.