Since year 1995 audi-vw car use engine immobiliser. The vag group immobiliser system consists of an immobiliser ecu which controls the recognition of keys and the engine management ecu system. Immo is activated when the ignition key is removed and, together with the engine control unit, largely prevents unauthorized starting of the engine. The system uses a transmitter and receiver unit in the ignition key (transponder). Whenever an attempt is made to start the engine, it transmits a new code to the car's electronics. The immobilizing is only cancelled if the key sends an authorization code.