194000193 - 5580E ANTI-THEFT DEVICE
FIAT CODE SYSTEM
The vehicles are equipped with an electronic system known as the FIAT CODE to produce the engine immobilizer function.The FIAT CODE system only allows the engine to be started by means of the NCM after a secret code, memorized previously in the NCM, is received.The second generation Code system is incorporated in the Body Computer Node (NBC). The FIAT CODE consists of 5 essential elements (in addition to the Body Computer which act as a control unit):- CAN line for dialogue between the NBC and the NCM- two-way serial line for recovery (W line);- two TEG devices (electronic key) containing a transponder with a secret code;- an (NTR) aerial that reads the code contained in the TEGs;- the NCM.Operation
The FIAT CODE allows the start of the engine management by the NCM by means of a coded dialogue between the NBC and NCM during the stage that precedes start up.After key on - i.e. TEG correctly inserted in the TEG Reader and turned to the ON position - the NCM sends a code request to the NBC, which responds only after it has identified (via its aerial) the presence of a known TEG.If the secret code in the answer 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 by means of a particular self-programming procedure described later on.Operation of the FIAT CODE is guaranteed if any of the other NBC functions are not working properly.After recognizing an enabled transponder, the FIAT CODE switches off any alarm system.Interaction between the fiat code and the electronic key (teg)
Every TEG contains a transponder with an IDENTIFICATION CODE and a SECRET CODE.As soon as the TEG is inserted, the transponder is energized and sends the identification code to the NTR which, having recognized it as one of the enabled ones, continues with the cryptographic transponder recognition strategy.If the identification code is not recognized, the procedure is aborted and the engine cannot be started.The cryptographic transponder 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 NTR attempts the transponder acquisition for up to 1 second.Communication between the engine control node and the fiat code
The dialogue between the NBC and the NCM is activated on the C-CAN in normal operating conditions. Every exchange of information between the NBC 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 engine control unit.If the NCM is blank, the procedure involves sending a fix-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 (the TEG must always be present in the TEG Reader).If the NCM is not memorized, the procedure involves a double exchange of secret codes between the NCM and the NBC.
Code recording
The CODE RECORDING procedure is the memorizing of the fix code in the engine control unit.Only after the NBC has memorized the identification codes, the secret code and the fix code, is the NBC ready to satisfy the request to transmit a code to a pristine NCM.After power on, the engine control unit initialises its software and requests a fix code if it is blank.If the NBC is not blank, it responds by sending the fix code, but only after having recognized an authorized TEG. If the TEG is not authorized (key unrecognized) or there is no TEG inserted, the NBC does not respond.If the FIAT CODE is blank and there is not a transponder in the TEG Reader, a FIX code request is sentf from the NCM to the NBC and the latter does not respond.Code verify
This standard procedure is repeated throughout the vehicle lifetime whenever the user inserts the TEG in the Reader and turns it to the ON position (KEY ON): this procedure enables the starting of the engine if the TEG is enabled.The code verify procedure continues even when the user places the TEG in the START position (CRANKING).When the TEG is inserted in the reader (NTR), the NBC recognizes whether the TEG transponder is one of the ones enabled (up to 8 TEGs available). If it is recognized, the steering is released and the TEG is enabled to rotate to the ON and START positions for engine starting.At the same time as the KEY ON, the NCM sends a starting authorization request to the NBC.In response to this request, the NBC only sends a response, encrypted by the Minikrypt, to the engine control unit if the transponder is recognized as enabled.If the NBC receives further verification requests, it only needs to re-read the transponder in the aerial before responding to the NCM if visible signs of tampering are present (see later).If the result of the transponder recognition is negative (incorrect transponder, no readable transponder, etc.), the NBC will send the code (incorrect transponder or missing transponder) to the engine management control unit and the vehicle protection system failure warning light in the instrument panel will come on.If the FIAT CODE is blank and the NCM sends a FIX code request, the FIAT CODE, after having recognized a transponder, will respond by refusing starting authorization.Method of using c-can or recovery line w
Communication between the NBC and NCM takes place along the C-CAN line by default: if the C-CAN line is faulty, the recovery strategy is as follows:- the NCM changes to recovery status on the W serial line and requests the code from the NBC: if the outcome is positive, start-up is permitted;- in the event of problems on the W line, the NCM transfers to recovery status by means of the Diagnostic instrument at the end of the retransmission attempts.The recovery strategy is mainly managed by the NCM, which acts as a master unit during communication: the NBC, acting as the slave unit, must always be ready to respond to code requests from the C-CAN network and also from the W serial line.Communication via the c-can network
Communication via the Body Computer and the NCM takes place via the following two CAN messages:- IMMO CODE REQUEST (immo code request)- IMMO CODE RESPONSE (immo code response).The IMMO CODE REQUEST is sent by the NCM and received by the NBC.The IMMO CODE RESPONSE is sent by the NBC and received by the NCM.Communication via the w line
If the system changes to recovery mode due to a malfunction in the CAN network, information must be exchanged between the NCM and NBC via the W serial line.This code exchange is only carried out for the CODE VERIFY procedure: it is not therefore possible to run a CODE RECORDING procedure via the W line.Information must be exchanged via the serial line in exactly the same way as via the C-CAN network: The NCM control unit is the communication master unit while the NBC control unit responds to requests received by the NCM.Both messages - IMMO CODE REQUEST and IMMO CODE RESPONSE - are carried on the serial line.CHECKING THE W LINE ELECTRICAL CONNECTIONBecause communication only takes place on the W line in recovery mode, an ERROR status would not not be recognised until the system was used i.e. because the customer would not be able to move the vehicle.A strategy for checking the W serial line has therefore been added so that the line can be diagnosed.About 1 second after the key on a code is sent on the W line to the NBC.If the NBC does not repeat it correctly, the fault will be signalled at the instrument panel for the activation of the passenger compartment protection system failure warning light (CODE) which will flash three times.Protection codes
The FIAT CODE function is performed via the exchange of secret codes between system subunits (TEG, NTR, NBC, engine management control unit).- UNIVERSAL CODE: this is the code that an unprogrammed NBC sends to the NCM when it detects the presence of a transponder in the TEG. 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.- IMMO CODE: This is the basic code that provides the secret code and the fix code. An automatically generated immo code is allocated to each vehicle. The IMMO CODE is used to generate all the other secret codes used by the FIAT CODE function.- SECRET CODE: This code is resident in the transponder. It is stored in the transponders contained in the TEG when the transponders are programmed and in the NBC when the keys are programmed at the end of line.- FIX CODE: This is stored in the NBC during end of line programming.- ELECTRONIC CODE (PIN): This is obtained from the fix code and 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 reprogram or program new remote control units (TEGs) and/or perform specific diagnostic functions.- IDENTIFIER: This is resident in the transponder and different for each transponder. It is stored in the FIAT CODE during the programming procedure. The NBC manages a table of enabled identifiers and another table of disabled identifiers.Fiat code function in the nbc/ntr
The FIAT CODE is a function of the NBC/NTR.The main FIAT CODE functions are:- to place the alarm in a deactivated state after recognizing an enabled TEG (NBC);- to energize the aerial to read the TEG transponder (NTR);- to send the random code to the transponder (NTR);- to receive the encrypted code transmitted by the TEG (NTR);- to store the secret code (NBC/NTR);- to manage a list of up to a maximum of 8 enabled identification codes (NTR);- to manage a list of 4 permanently disabled identifiers (NTR);- to manage the C-CAN line towards the engine control unit (NBC);- to control activation of the warning light on the panel via communication with the NQS (NBC);- to carry out autodiagnosis (NBC/NTR).Aerial
The aerial is located in the TEG Reader from where it is also managed.Since the aerial needs to be as close as possible to the transponder (on account of electro-magnetic immunity, the limited range of the transponder and small dimensions) it is fastened to the front part of the TEG-Reader.Transponder (in the teg)
A cryptographic transponder is located inside the TEG.Operation
At the time of the +15, the transponder is energised by the aerial and responds by emitting a rolling, encrypted secret code.If the code is recognized as valid, the NBC sends the engine control unit, on request, a coded signal allowing the engine to be started.Up to 8 electronic keys (TEGs) can be stored in the NBC. | The TEGs are supplied already memorised by the production plant. All the codes are also stored in a database managed by Parts. When the new vehicle is delivered to the customer, the service network does not need to carry out any memorisation procedure. If the TEGs are lost or extra TEGs are required, order from Parts in accordance with the procedures described below and in the REPAIR PROCEDURES section. |
Specifications
The transponder in the TEG has the information required for a coded dialogue with the TEG Reader encoded in its memory.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.Programming the teg
The memorisation procedure is divided into two stages in sequence:- the transponder in the TEG is stored in the NTR;- The NBC manages memorisation of the fix code in the engine control unit.This second stage is implemented automatically when the first is completed successfully after key on.The transponders are sent to the TEG manufacturer programmed with the identifier (different for each transponder).The manufacturer generates an immo code, computes the relevant codes (secret code, fix code) and programmes the secret code and the programming date in the transponders.Once programmed, it prints a bar code on a disposable label that contains the immo code, the TEG identifiers, the programming date, the emergency key mechanical code (door opening).The secret code contained in the TEGs is used the encrypted algorhithm for recognition of the TEG.Programming a new body computer
If the Body Computer is replaced, the NBC must be programmed with the secret code and fix code of the vehicle on which it will be installed.The database is accessed using the chassis number to obtain the vehicle immo code. This is used to supply the secret code and fix code, which are programmed in the NBC.Once the NBC has been installed in the vehicle, the TEG identifiers are stored (see reprogramming).An NBC programming operation can only be performed with a blank NBC by the FIAT parts dept.Reprogramming the teg
TEG reprogramming involves storing the TEGs enabled upon vehicle start-up in the NTR.New TEGs to be programmed and TEGs already programmed will be entered in the NTR so that they can be recognised by the TEG Reader, which stores those presented during the procedure in the enabled identifier table and transfers those not presented from the table to the disabled identifier table.Disabled teg table
If an enabled TEG is no longer available (lost, stolen or no longer operational), its operation must be disabled during the subsequent programming procedure (necessary to memorise a new replacement TEG for example).The TEG Reader manages a table in the EEPROM that can contain data on 4 disabled TEGs: the identifiers of enabled TEGs not presented during the reprogramming procedure are transferred to this table.If the disabled TEG table is full, any new TEG will replace the first entered in the table.This table also allows t| ... DATA ERROR - CROPPED TEXT | Ошибка данных - Текст обрезан ... |
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