To increase protection against theft attempts, an engine immobilizer system known as the FIAT CODE is used.The CODE system only allows the engine to be started by means of the engine managementn control unit after a secret code, memorized previously, is received.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 Code system control unit is incorporated in the Body Computer and also includes:- C CAN line for dialogue with the Body Computer and the engine management control unit;- electronic keys contained in a transponder with a secret code;- an aerial that reads the code contained in the transponder;- engine management control unit.The CODE allows the start of the engine management by the engine management control unit by means of a coded dialogue between the Body Computer and the engine management control unit during the stage prior to starting.After the key is turned to the ON position, the engine control unit sends a code request to the Body Computer which only responds after having recognized (via the aerial) a known transponder in the ignition switch.If the secret code in the answer is valid, the engine management control unit continues with the regular engine management activities, allowing the engine to be started up.If the transponder is not recognised, engine start-up is inhibited.Operation of the CODE is guaranteed if any of the other Body Computer functions are not working properly.The function also includes the display of the status by means of the CODE warning light in the instrument panel, connected via the CAN, coming on.The function also includes the display of the status by means of the CODE warning light in the instrument panel, connected via the CAN, coming on. See descriptions 5580E ANTI-THEFT DEVICE