printable version

Diagnosis of the engine management system

System of onboard self-diagnostics (OBD)

Described in this manual model equipped with second-generation on-board diagnostics (OBD II).

Data read OBD II system is made using a special scanner, for example, Consult-II, connected to the 16-pin diagnostic connector (DLC) via a cable with a special cable adapter. Using the same scanner is carried out and cleaning the processor memory. Running the DTC procedures for reading and cleaning ECM memory is wise to instruct the service station specialists.

Data on diagnostic devices

Check of serviceability of functioning of components of systems of injection and decrease in toxicity of exhaust produced by means of a universal digital meter (DMM). Using a digital meter is preferred for several reasons. First, on analogue devices it is difficult enough (at times - impossible) to determine the result of readings with an accuracy of hundredths and thousandths of, while at inspection of the contours including in the structure electronic components, such accuracy takes on special significance. The second, no less important reason is the fact that the internal contour of a digital multimeter, has high enough impedance. As the voltmeter is connected to a checked chain in parallel, accuracy of measurement is higher, the less current will flow through the device itself. This factor is not significant when measuring relatively high voltages (9 ÷ 12), but becomes the determining the diagnosis of issuing low voltage components, such as, for example, lambda probe, which refers to the measurement of a volt.

Parallel monitoring of signal parameters, resistance and voltage in all control circuits possible using a splitter connected in series to the engine control unit connector. Thus on the switched off or the engine is running, or while driving, the signal parameters are measured at the terminals of the hub, from which a conclusion about possible defects.

For the diagnosis of electronic systems can be used special diagnostic scanners or testers with a certain cartridge (if provided), a universal cable and connector. In addition, for this purpose, you can use a specialized automotive diagnostic computer specially developed for full diagnostics of the majority of systems of modern cars (for example, ADC2000 firms Launch HiTech). Also, for this purpose can apply scanners and specialized diagnostic analyzers, eg, FDS 2000, Bosch FSA 560, KTS500 (0684400500) or a conventional personal computer with a special adapter cable (for example, set 1 687 001 439) and the installed program browser OBD II.

Some scanners, besides usual operations of diagnostics, allow, when connecting to a personal computer to print data stored in the control unit electrical circuit diagrams (if incorporated), anti-theft system to program, monitor signals in the circuits of the vehicle in real time.

Organize contacts the DLC