The Passenger Comparatment Protection system (CODE or immobiliser) prevents the engine being started by unauthorised persons by inhibiting the operation of the engine control unit through recognition of a mechanical key at the time of start-up.The vehicle electronic key contains a coded insert and a transponder for individual safety recognition.When the mechanical key is inserted in the ignition switch and turned ON, the steering is released, the instrument panel is activated, the electrical users are available and the Passenger Compartment Protection system identifies the key by mean of the transponder it containsIf the transponder secret code corresponds to one of those accepted by the vehicle (up to 8 available keys), the CODE system enables engine start-up.All the codes for the enabled keys and the code used in the dialogue with the engine management control unit are contained in the unit:when the key is turned to the ON position for the first time, if the key is correctly recognized, this code is transferred to the engine management control unit which remains indelibly linked to the Code unit and therefore to the Body Computer.If the transponder is not recognised, the Passenger Compartment Protection (CODE) warning light lights up on the instrument panel and the Passenger Compartment Protection System fault message appears on the panel display. Engine start-up is inhibited.For further details of Description and Operation Op. 5580E ANTI-THEFT DEVICE