Anti-theft device as an immobiliser on a motor vehicle

摘要

The invention relates to an anti-theft device as an immobiliser on a motor vehicle having a vehicle key (21) in which a transponder (23) is integrated and having an ignition lock (22) in the vicinity of which there is a transmission coil (26) with connected read-out and evaluation electronics (27). In a control unit, the transponder code which is received from the read-out electronics (27) when the ignition switch is actuated is compared with a stored code for identification. In the event of the codes being identical, a component (30) whose operation is blocked when the vehicle is parked is enabled again. According to the invention, a new vehicle key with an associated transponder code for the vehicle is made capable of being used by means of an initialisation process in that an initialisation code is entered via a manually activated control element (9, 10) for inputting digital information. When identity between the initialisation code which has been input and an initialisation code which has been previously stored in a memory is established, the storage of the new transponder code in the memory is enabled. As a result, it is possible to replace a defective key or to authorise further keys for the use with the vehicle.