To increase protection against theft attempts, an engine immobilizer system known as the FIAT CODE is used.All the keys are equipped with an electronic Transponder device that sends a coded signal to a special control unit (incorporated in the Body Computer): if it recognizes the code sent, it allows the engine to be started.The code used in the dialogue, that takes place via an aerial coaxial to the ignition switch, varies each time the engine is started (rolling code): therefore the code cannot be reproduced even using electronic scanners.The main function of the Code control unit is to recognize the key inserted in the ignition switch: it contains the secret code used in the dialogue with the key transponder; the unit also memorizes all the codes for enabled keys and the code used in the dialogue with the engine management control 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.The dialogue between the two units takes place via the CAN and a two-way recovery serial line (W line) used if the CAN is faulty.The Body Computer makes the information available to the CAN which switches on: the special "CODE failure" warning light in the instrument panelFor more details See descriptions 5580E ANTI-THEFT DEVICE.