Abstract: In a method of protecting against unauthorized use of a vehicle having a communication structure for exchange of data between a receiving unit, a use protection and control unit and at least one operationally essential system control, a master station broadcasts a signal defining use restrictions applicable to the vehicle, and the use protection and control unit aboard the vehicle checks for violation of the use restrictions, and disables the at least one operationally essential system control if a violation is detected.

Abstract: An electronic vehicle key has a radio receiver for receiving radio call information which is transmitted by a control center, and a key communication device for communicating with a vehicle communication device in an associated vehicle, signals transmitted by the key communication device to the vehicle communication device serving to activate or deactivate an immobilizer on the vehicle. According to the invention, a key controller, which administers a mobility account, is provided in the electronic vehicle key; and radio call information is transmitted by a control center is registered as a “credit” in the mobility account. Relevant events are processed as “debits” in the mobility account, and deactivation or activation of the immobilizer on the vehicle is dependent on the account value of the mobility account.

Abstract: An electronic vehicle key has a radio receiver for receiving radio call information which is transmitted by a control center, and a key communication device for communicating with a vehicle communication device in an associated vehicle, signals transmitted by the key communication device to the vehicle communication device serving to activate or deactivate an immobilizer on the vehicle. According to the invention, a key controller, which administers a mobility account, is provided in the electronic vehicle key; and radio call information is transmitted by a control center is registered as a “credit” in the mobility account. Relevant events are processed as “debits” in the mobility account, and deactivation or activation of the immobilizer on the vehicle is dependent on the account value of the mobility account.

Abstract: The invention relates to a method for protecting against unauthorized use of a vehicle which has bidirectional communication with a master station, whereby it is possible not only to transmit exclusively a position message of the vehicle to the master station or to transmit exclusively enabling signals to the vehicle from the master station, but also to make the communication appropriate to requirements. The necessary transmission of information is substantially reduced in that the enabling signal is broadcast only when requested by the vehicle. On the other hand, it is still not possible for the enabling to be carried out at the vehicle end only.