To increase the protection against theft attempts, an electronic immobiliser system known as the ALFA ROMEO CODE system is adopted.The keys are equipped with an electronic transponder which transmits a coded signal to a special electronic control unit in the Body Computer. This allows the engine to be started if the code is recognised.The code used in the communication, which takes place via aerial, changes each time the car is started up (rolling code). The code cannot therefore be reproduced, even with electronic scanners.The main function of the Code control unit is to identify the code in the ignition key. The control unit contains a secret code which is used to communicate with the key Transponder. The body computer contains all enabled key codes in its memory, together with the code used in the communication between the body computer and the engine management unit. When the key is turned to MAR for for the first time, if the key is identified correctly, the code is transferred to the engine management unit and is then indelibly linked to the body computer.The two units communicate via a two-way serial line.The function also allows status to be displayed via activation of a warning light (ALFA ROMEO CODE warning light) in the instrument panel and connected via the CAN network.For more details Characteristic of working principle 5580E ANTI-THEFT DEVICE.