312000794 - 5580E ANTI-THEFT DEVICE

SPECIFICATIONS

The vehicles are equipped with an electronic system known as the FIAT CODE II to produce the engine immobilizer function.The FIAT CODE system (via the Body Computer) only allows the engine to be started by means of the Engine Management Node (NCM) after a secret code, memorized previously in the NCM, is received.

System details

The second generation Code system is incorporated in the Body Computer Node (NBC).

COMPOSITION

The FIAT CODE consists of 5 basic elements:

  • CAN line for dialogue with the NBC and the NCM;
  • Body Computer Node (NBC);
  • electronic keys contained in a transponder with a secret code;
  • an aerial that reads the code contained in the key transponders;
  • Engine Management Node (NCM).

OPERATION

Introduction

The FIAT CODE allows the start of engine management by the NCM by means of a coded dialogue between the NBC and NCM during the stage that precedes starting.After the key is turned to the ON position, the NCM sends a code request to the NBC which only responds after having recognized (via the aerial) a known electronic key in the ignition switch. If the secret code provided is valid, the NCM continues with the regular engine management activities, allowing the engine to be started up.The NCM can only memorize the secret code through a special procedure.

Interaction of the fiat code with the key

Each key contains a transponder with a SECRET CODE.As soon as the key is turned to MAR, the transponder converses with the NBC which, having recognized it as one of the enabled ones, continues with the NCM recognition strategy.If the identification code is not recognized, the procedure is aborted and the engine cannot be started.The SECRET CODE is recognized by means of a challenge-response algorithm with an encrypted code exchange.The code recognition time is less than 160 ms per attempt.The FIAT CODE attempts to acquire the transponder signal for up to 1.3 seconds.

Dialogue between engine management node and fiat code

The dialogue between the FIAT CODE (NBC) and the NCM control units takes place via the C-CAN.Every exchange of information between the FIAT CODE and the NCM is guided by the NCM (the NBC never interrogates the NCM but only responds after a request).After KEY-ON, the flow of code exchange operations between the NBC and the NCM depends on the status (blank or memorised) of the NCM.If the NCM is pristine, the procedure involves sending the SECRET CODE request to the NBC: in this way the NCM learns the secret code and stores it in its memory.This procedure is known as CODE RECORDING.If the NCM has already been programmed, the procedure involves checking that the codes stored in the Engine Management Control Unit memory and the one memorized in the NBC correspond.This procedure is known as CODE VERIFY.
1. Key-ON2. NCM initialization3. NCM status memorized OK, pristine OKA. CODE VERIFY7. is the code valid?8. engine operation is allowed9. engine operation is not allowedB. CODE RECORDING4. is the recording completed correctly?5. engine operation is allowed6. engine operation is not allowedCode recordingThe CODE RECORDING procedure is the memorizing of the fix code in the Engine Management Control Unit Node.Only after the NBC has memorized the identification codes and the secret codes, is the NBC ready to satisfy the request to transmit a code to a blank NCM.After a key on, the Engine Management Node initializes its software and requests the secret codes if it is blank.If the NBC is not blank, it responds by sending the secret codes, but only after having recognized an authorized key. If the key is not authorized (unrecognized) or there is no key, the NBC does not respond.If the NBC is pristine and there is no transponder in the key and a request is sent for secret codes from the NCM, the NBC does not respond.Code verifyThis is the standard procedure that is repeated during the life of the vehicle each time the user insesrts the key in the ignition and turns it ON. this procedure enables the starting of the engine if the key inserted is enabled.If it is not completed, the Code Verify procedure continues even when the user turns the key to the starting position.After the key is in the ON position, the NBC recognizes whether the transponder in the key is one of those that is enabled. At the same time, with the key in the MAR or AVV position, the NCM initializes its software to check whether the secret codes have been memorized. If the answer is yes, it sends a request to the NBC.In response to this request, the NBC only sends the secret encrypted codes to the Engine Management Node if the transponder is recognized as enabled.If the result of the transponder recognition is negative (incorrect transponder, no transponder in the key, etc.), the NBC will send a negative authorization response to the Engine Management Node.If the NBC is blank and the NCM sends a request for secret codes, the NBC, after having recognized the presence of a recognized transponder, responds by sending a positive authorization reply.

Protection codes

The protection codes used by the NBC and NCM are listed below.UNIVERSAL CODE: this is the code that an unprogrammed NBC sends to the NCM when it detects the presence of a transponder in the key.The vehicle protection warning light comes on at a frequency of 1.6 Hz and duty cycle of 50%.The warning light flashes to indicate that the system is properly connected but the vehicle is not protected by a code.
1. Vehicle protection system fault warning light - Fiat CODE (amber)SECRET CODES: These codes are stored in the transponders contained in the keys when the transponders are programmed and in the NBC when the keys are programmed at the end of line.ELECTRONIC CODE (PIN): This is printed on the CODE CARD, which is given to the vehicle owner. It takes the form of a 5-figure decimal code (0 is not permitted).It is used to access the NBC memory in protected mode in order to reprogramme or programme new remote control keys and/or perform specific diagnostic functions.IDENTIFIER: This is resident in the transponder and different for each transponder.It is stored in the NBC during the programming procedure. The NBC manages a table of enabled identifiers and another table of disabled identifiers.

DESCRIPTION OF THE COMPONENTS

Body computer

The main functions of the NBC are:

  • recognizing the introduction and rotation of a key in the ignition (MAR);
  • conversing with the key transponder by means of the immobilizer aerial;
  • storing up to 8 identification codes;
  • memorizing the secret code;
  • managing a list of 4 permanently disabled identifiers;
  • managing the CAN line towards the Engine Management Node;
  • managing the activation of the warning light on the panel via communication with the instrument panel;
  • carrying out the autodiagnosis for the CODE system functions.
Supply of fiat code as sparesIf the FIAT CODE function has to be replaced, the entire Body Computer must be replaced.To replace the Body Computer, request it from the Parts Dept., providing the vehicle chassis number.

Aerial

CompositionThe aerial assembly comprises an toroid type aerial with a connector built into the aerial body and has an ohmic value of 34 Ohm ± 5%.The wiring connected to the NBC is incorporated in the front cable loomOperationThe aerial is supplied with power by the NBC to energize the key transponder.Since the aerial needs to be as close as possible to the transponder (on account of electro-magnetic immunity, the small dimensions and limited range of the transponder) it is fastened axially to the ignition switch.
1. CODE aerial2. Ignition switch

Ignition key

OperationThe mechanical key contains a cipher transponder in the grip.The moment the key is inserted in the ignition and turned to the ON position, the transponder is energized by the aerial and responds by emitting the rolling, encrypted secret code.If the code is recognized as valid, the NBC sends the NCM, on request, a coded signal allowing the engine to be started.Up to 8 keys can be programmed in the NBC.
The keys are supplied already memorised by the production plant. All the codes are also stored in a database managed by the Parts Dept. When the new vehicle is delivered to the customer, the service network does not need to carry out any memorisation procedure. If the keys are mislaid or additional keys are required, make the request to the Fiat Parts Dept.
Transponder in the key

The transponder in the key has the following stored in its memory:

  • SECRET CODE;
  • IDENTIFIER, which is different for each transponder produced;
  • PROGRAMMING DATA for the secret code.
The identification code differs from transponder to transponder to guarantee that no two transponders have the same identification code even if there is a request for a duplicate in the Network.Reprogramming keysReprogramming the keys involves storing the keys enabled upon vehicle start-up in the NBC.Both the new keys to be programmed and those already programmed are inserted into the ignition to be recognized by the NBC: this memorizes the keys presented during the procedure in the enabled identification codes tables and transfers those no longer presented to the disabled identification codes table.Disabled keys tableIf an enabled key is no longer available (mislaid, stolen or no longer working), the subsequent key programming procedure (in which the key is no longer presented) disables its operation.The NBC manages a table in the EEPROM that can contain data on 16 disabled keys: the identifiers of enabled keys not presented during the reprogramming procedure are transferred to this table.If the disabled keys table is full, any new key will replace the first entered in the table.This table also allows keys used on the vehicle to be traced.Key reprogramming procedureThe key reprogramming procedure is performed/guided by the EXAMINER Diagnostic Equipment: this procedure is activated by means of access protected by the vehicle PIN. Continue following the instructions for the diagnostic equipment.
It is possible to program up to 8 enabled keys.
Deleting a lost key from the memoryAt any time it is possible to delete a lost key from the memory using the EXAMINER Diagnostic Equpment. The identifier of this key is transferred to the disabled identifier table and will no longer be recognised.

Code card

This Code Card contains:

  • the emergency code (electronic code) that allows the vehicle to be started using the EXAMINER and which is also used to programme the keys and remote controls using the EXAMINER;
  • the key mechanical code identifies the mechanical profile of the key and must be specified on the order to receive the key already cut.
1. Electronic code2. Mechanical codeThe electronic emergency code is also used for system diagnosis and for other operations using Examiner. Many of these operations (e.g. key programming) can be carried out only once this code has been entered.Before any operation, it is therefore necessary to ask the Customer for their Code Card.The electronic code is used in the case of emergency starting.
The Code Card must not be left in the vehicle in case it is stolen.

"vehicle protection" warning light

The vehicle protection warning light is located in the instrument panel and is controlled by a message from the NBC on the B-CAN.Vehicle protection warning light flashing modeThe NBC controls the switching-on of the vehicle protection warning light in the panel, via the CAN, flashing in order to signal programming errors for the Body Computer or the NCM.In this case the diagnostic equipment must be connected and the instructions followed.

FAULT DIAGNOSIS

The FIAT CODE function allows self-diagnosis to be carried out for system components.The NBC is capable of identifying and memorizing the presence of the following malfunctions in its EEPROM:

Transponder:

  • defective or missing, or secret code incorrect
  • deleted/disabled
  • unknown/not memorized

Transponder aerial:

  • electrical connection defective (circuit open, short circuit to earth or to battery)

Active diagnostics

By means of commands sent from the Diagnostic instrument, it is possible:

  • request the current system status
  • control the activation/deactivation of the CODE warning light at the NQS.

Recovery procedure using the accelerator pedal

If the Fiat CODE system does not manage to deactivate the engine immobilizer function the "VEHICLE PROTECTION (1) and "EOBD ENGINE MANAGEMENT SYSTEM FAILURE" (2) warning lights in the instrument panel will remain on and the engine will not start.
The emergency starting procedure must therefore be used to start the engine.It is advisable to read the entire procedure carefully first: if you make a mistake, turn the ignition key OFF and repeat the operations from the beginning.

Proceed as follows:

  • read the 5 digit electronic code from the CODE card;
  • turn the ignition key to the ON position;
  • fully depress the accelerator pedal and keep it pressed: the warning light (2) in the instrument should come on for about 8 seconds and then go out;
  • release the acceler
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