7.4.3. Device and purpose of the antenna block of an immobilizer («Smartra»)

Fig. 7.78. Priyemootvetchik

At ignition inclusion the frame aerial gives out energy on a priyemootvetchik which accumulates energy in the condenser.

As soon as energy delivery from the frame aerial stops, the priyemootvetchik issues confidential data, using the saved-up energy.

In a priyemootvetchik the advanced algorithm of coding is used. When programming key special data of the car which register in memory of a priyemootvetchik are entered into a priyemootvetchik. Record disposable owing to what it is impossible to add or change contents of memory of a priyemootvetchik.

Fig. 7.79. Antenna immobilizer block

The Smartra block provides communication with the priyemootvetchik which has been built in the ignition key. Communication is carried out on a radio frequency of 125 kHz. The Smartra block is established on the ignition switch near a frame send-receive radio antenna.

The radio-frequency signal accepted by the frame aerial will be transformed by the Smartra block to messages of serial communication. The messages accepted from the control unit by the engine, will be transformed to a radio-frequency signal which via the aerial is transferred and a key priyemootvetchik.

The Smartra block does not make check of correctness of recognition of a priyemootvetchik and calculation of algorithm of coding. It is only advanced interface which will transform a flow of radio-frequency data from a priyemootvetchik to a series of messages on the control unit the engine, and on the contrary.

Fig. 7.80. Control unit engine

The control unit the engine checks the ignition key on special algorithm of coding which is at the same time programmed in a priyemootvetchik and the control unit by the engine. Start of the engine is possible only at coincidence of results of action of algorithms. Data of priyemootvetchik of all operating keys of the car are stored in memory of the control unit by the engine.

Fig. 7.81. I will corrode data lines

Diagnostic codes are read out by accession to the voltmeter or Hi-Scan2 device socket.

Fig. 7.82. Diagnostic device

The device has the ICM functions («Smartra»), ESM (the control unit the engine), diagnostics and key replacements.

If the control unit determines by the engine malfunction of the Smartra block or a priyemootvetchik, it will involve function of emergency start of the engine in immobilizer system. Emergency start is possible only if into memory of the control unit the engine earlier entered the password of the user (4 figures). The password gets out the owner of the car and is entered at service station. For emergency start the control unit will be unblocked by the engine on 30 with only provided that the control unit the engine and the password of the user are in a condition "is programmed" and the entered password of the user is correct. The engine can be started only during this time, on then start becomes impossible.

At issue of the wrong password of the user the control unit the engine rejects request for start within one hour. Duration of this deviation cannot be reduced by shutdown of the storage battery or any other actions. After battery connection the timer reckons from scratch.

Function of emergency start can be activated also by means of the ignition key. Thus the password of the user stands out on the control unit the engine by special sequence of inclusions and ignition switching off. The control unit will be unblocked by the engine on 30 with only provided that the control unit and the password of the user are in a condition "is programmed" and the entered password of the user the correct. The engine can be started only during this time, then start becomes impossible. After input of the new password the timer reckons the 30-second period from scratch.

After ignition switching off the control unit is blocked by the engine after 8 pages. The following start needs repeated input of the password of the user.

The system of diagnostics supervises:

– communication between the control unit the engine and the Smartra block;

– operation of the Smartra block and priyemootvetchik;

– being stored in memory of the control unit the engine the data relating to work of an immobilizer.

Errors of an immobilizer are divided into three groups, each of which includes four typical mistakes (malfunction of schemes, a range schemes / deviation of characteristics, low level of a signal / high level). This classification of mistakes is presented on the provided table.

The faulty control unit the engine is replaced with the "pure" or "neutral" block. Thus all keys are necessary for programming in the new block. The keys not programmed in the new block will not operate (see procedure of programming of keys). As to change programming of priyemootvetchik it is impossible, special data of the car should remain without change.

At replacement of the Smartra block of any special procedures it is not required. Instead of the old Smartra block the new is established. In this device it is not stored any data connected with a priyemootvetchik.

The control unit is given by the engine in a "neutral" condition by means of the verifying device.

The car key is inserted into the lock of ignition, and at ignition inclusion its data register. The control unit the engine requests special data of the car from the verifying device. Messages of communication are defined as «a neutral mode». After successful reception of data of the control unit by the engine passes to a neutral condition.

The control unit the engine remains blocked and does not provide a mode of emergency start and function «double inclusion of ignition».

Programming of keys is made as well as for the "pure" control unit by the engine. Owing to impossibility of change of programming of priyemootvetchik special data of the car should remain without change. For change of data it is necessary to have new naturals a pure priyemootvetchik.