The CODE (or immobilizer) system prevents the starting of the
engine, preventing the operation of the engine control unit, by
recognising the mechanical key at the time of starting.At each start-up, when the ignition is turned
on, the body computer node (which integrates the Fiat CODE system),
sends to the engine control unit a recognition code to de-activate the
block on functions. The recognition code, crypted and varying from
among over four thousand million possible combinations, is only
sent if in turn the system's control unit has recognised, via an
aerial which is wrapped around the ignition switch, the code transmitted
by the key.When the electrical devices are switched
on, the CODE system identifies the key via the transponder contained
in the key: if the transponder's secret code corresponds to one
of those accepted by the car (up to 8 available keys), the CODE
system enables engine starting.If there is a fault on the CODE system and
the recognition of the transponder key has had a negative result,
the CODE warning light (or message on the display) remains on.However, an emergency manoeuvre can be carried
out, which allows the engine to be started after introduction of
the ELECTRONIC CODE present on the CODE CARD in the customer's possession.The code is entered by a sequence of presses
of the accelerator pedal ('gas pedal' procedure).