Abstract: The invention provides a device for protection against unauthorized use of a motor vehicle, in which usage authorization information is transmitted electromagnetically, at preset time intervals, by a transmitter in a predetermined vehicle usage area. A usage control device aboard a vehicle keeps an operational critical vehicle assembly or assemblies that are operationally essential in operational readiness after a usage signal is received for only a predetermined subsequent period of time, and blocks further operation if further usage signals are not received within the predetermined time period.