System components

To increase protection against attempted theft, the cars have been fitted with an electronic engine immobiliser system known as a Fiat Code system. The engine can be started only if the code is recognised. The Fiat Code system (immobiliser) consists of:

• Fiat Code control unit;
• electronic keys (three or four according to the car model). These contain a device that emits an electronic code;
• special aerial on the ignition key;
• engine control unit with a serial line communicating with the Fiat Code control unit;
• Code Card with a secret code for the emergency start-up procedure;
• Code warning light.

Functions of the Fiat Code control unit are as follows:

• to recognise the action of inserting a key in the ignition and turning it;
• to emit an electromagnetic field to power up and activate the key TRANSPONDER (code emitter);
• to receive the secret code emitted by the key;
• to store up to 8 keys with the same number of electronic codes;
• to manage code checking/processing;
• to manage serial, two-way unifilar communication with the engine management unit;
• to manage activation of a special warning light;
• to recognise connection with the tester station and set the serial line to test mode on some versions.

The Fiat Code system enables engine management unit operation by means of an exchange of codes. When the ignition is ON (+15), the engine control unit sends a code request to the Fiat Code unit. This responds and sends a secret code only after recognising (by means of its aerial) insertion of a known electronic key into the ignition.

Once the code has been identified, the engine control unit switches to engine start-up enablement mode. The engine control unit can only store the secret code by means of a specific procedure.

SYSTEM COMPONENTS

Engine management control unit

The engine control unit is the basic component of the Fiat Code system because it contains the Master Code.

According to the model/version, the engine control unit consists of the following versions:

• injection-ignition electronic control unit for petrol versions with integral injection and ignition system.