Diagnostics of a control system of the engine. BMW the 7th E38 series (from 1994 to 2002 release)
BMW 7_aya the E38 series from 1994 to 2002
1. Introduction
2. Governing bodies and methods of operation
3. Settings and routine maintenance of the car
4. Engine
5. Cooling systems of the engine, heating, ventilation and air conditioning
6. A power supply system and production of the fulfilled gases
7. Systems of electric equipment of the engine
7.1. Systems of ignition, preheat and engine management
7.1.1. Main data and security measures
7.1.2. Search of malfunctions - the general information and preliminary checks
7.1.3. Diagnostics of a control system of the engine
7.1.4. Replacement of candles and coils of ignition
7.1.5. Replacement of rotors of distributors of ignition
7.1.6. Replacement of candles of an incandescence
7.1.7. Removal and ECM installation
7.1.8. Replacement of sensors of a control system of the engine
7.2. Systems of a charge and start
8. Manual box of gear shifting and coupling
9. Automatic transmission
10. Cardan and power shafts, reducer, differential and stupichny assemblies
11. Brake system
12. Suspension bracket and steering
13. Body
14. Onboard electric equipment
15. Schemes of electric equipment


7.1.3. Diagnostics of a control system of the engine

System of onboard self-diagnostics (OBD)

Models are equipped with system of onboard diagnostics of the second generation (OBD II).

Data read-out of the OBD II system is made by means of the special scanner, for example, of Consult-II connected to the 16-contact diagnostic socket (DLC) by means of a cable of a special cable with an adapter. 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.

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, 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, 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), 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, cable (for example, set 1 687 001 439) and the installed program the OBD II browser.

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, 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.

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7.1.2. Search of malfunctions - the general information and preliminary checks
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7.1.4. Replacement of candles and coils of ignition