To increase protection against theft attempts, an electronic
immobilizer system known as the 'FIAT CODE' system has been 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.