7.2.1. General information
Tires of data and system of onboard self-diagnostics (OBD)
All control units, their sensors and actuation mechanisms (except ABS blocks, adjustment of an inclination of headlights and an additional heater of diesel models) are united in the uniform system consisting of two tires of data transmission: P-tire (tire of data of the power unit) and I-tire (tire of these devices). Both tires are connected to a combination of devices (MIU) and data of any control unit are available to all other blocks. On models without the TC or ESP systems data on car speed (from the ABS block) move directly to MIU and also are available to all systems of the car. On other models data on the speed of the car arrive either from the TC/ABS block, or from the ESP block, connected to the P-tire.
Organization of the tire of data
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Contacts of the DLC socket No. 3
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4 — Connection with the case |
7 — the Line K of diagnostic data (ISO 9141-2) |
The models described in the present manual are equipped with system of onboard diagnostics of the second generation (OBD II) for access to which the block of electronic control by the dashboard (DICE) connected to the I-tire is used.
Data read-out of the OBD II system is made by means of the special scanner connected to the 16-contact diagnostic socket (DLC). By means of the same scanner also processor memory cleaning is carried out. Performing procedures of reading of the DTC codes and cleaning of memory of ECM will be reasonable to charge to experts HUNDRED.
The diagnostic socket used for contact with the scanner is organized according to ISO 9141-2.
Data on diagnostic units
Check of serviceability of functioning of components of systems of injection and decrease in toxicity of OG is made by means of the universal digital measuring instrument (multimeter). Use of the digital measuring instrument is preferable for several reasons. First, on analog devices it is rather difficult (sometimes - it is impossible), to define result of the indication to within the 100-th and thousand shares while at inspection of the contours including electronic components in the structure, such accuracy is of particular importance. The second, not less important, the fact that the internal contour of a digital multimeter, has rather high impedance is the reason. As the voltmeter is connected to the checked chain in parallel, the accuracy of measurement of subjects is higher, than smaller current will pass through actually device. This factor is not essential at measurement of rather high values of tension (9 - 12 V), however becomes defining at diagnostics of the elements giving low-voltage signals, such as, for example, lambda probe where it is about measurement of shares of volt.
Parallel observation of parameters of signals, resistance and tension in all chains of management is possible by means of the splitter included consistently in the socket of the control unit of the engine. At the same time on the switched-off or working engine, or during the movement of the car, measurement of parameters of signals on splitter plugs is performed from what the conclusion about possible defects is drawn.
Special diagnostic scanners or testers with a certain cartridge (if it is provided), a universal cable and the socket can be used to diagnostics of electronic systems of the car. Besides, it is possible to use the specialized automobile diagnostic computer which is specially developed for full diagnostics of the majority of systems of modern cars to this purpose (for example, ADC2000 of Launch HiTech). Also, it is possible to use scanners and specialized diagnostic analyzers to this purpose, for example, FDS 2000, Bosch FSA 560 (www.bosch.de), KTS500 (0 684 400 500) or the ordinary personal computer with the special adapter, a cable (for example, a set 1 687 001 439) and the installed program the OBD II browser.
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The free version of the OBD II browser can also be "downloaded" from the website of authors of the present manual http://arus.spb.ru. |
Some scanners, besides usual operations of diagnostics, allow to print out, at connection with the personal computer, the schematic diagrams of electric equipment which are stored in memory of the control unit (if those are put), to program anticreeping system, to observe signals in car chains in real time.