On-Board Diagnostics (OBD) System
1. The models described in this Manual are equipped with the European On-Board Diagnostics (EOBD) system.
2. Reading OBD system data and clearing the processor memory is performed using special diagnostic equipment connected to the diagnostic connector (DLC) - see illustration. It would be reasonable to entrust the procedures of reading/erasing DTC codes and clearing the ECM memory to service station specialists. The diagnostic K-line is used only for diagnosing the engine management system and DSG transmission (see illustration 1.1). Diagnostics of other control units is carried out via the CAN bus.
4.2. Connecting the diagnostic device
Information about diagnostic devices
3. Checking the proper functioning of the injection system components and reducing exhaust toxicity is carried out using a universal digital meter (multimeter). Using a digital meter is preferable for several reasons. Firstly, it is quite difficult to use analog devices (sometimes - impossible), determine the reading result with an accuracy of up to hundredths and thousandths, while when examining circuits that include electronic components, such accuracy takes on special significance. The second, no less important, reason is the fact that the internal circuit of the digital multimeter has a fairly high impedance. Since the voltmeter is connected to the circuit being tested in parallel, the accuracy of the measurement is higher, the less current passes through the device itself. This factor is not significant when measuring relatively high voltage values (9:12 V), but it becomes decisive when diagnosing elements that produce low-voltage signals, such as, for example, a lambda probe, where we are talking about measuring fractions of a volt.
4. Parallel monitoring of signal parameters, resistances and voltages in all control circuits is possible using a splitter connected in series to the engine control unit connector. In this case, with the engine turned off or running, or while the vehicle is moving, the parameters of the signals at the terminals of the splitter are measured, from which a conclusion is made about possible defects.
5. For diagnostics of electronic systems, it is recommended to use the VAS5051 B diagnostic complex, or the VAS5052 or VAS5053 diagnostic tester. In addition, for this purpose, you can use a specialized automotive diagnostic computer, specially designed for complete diagnostics of most systems of modern cars (for example, ADC2000 from Launch HiTech). For this purpose, you can also use scanners and specialized diagnostic analyzers, such as FDS 2000, Bosch FSA 560, or a regular personal computer with a special adapter, cable, and installed OBD II browser program.
6. Some scanners, in addition to the usual diagnostic operations, allow, when connected to a personal computer, to print out the basic diagrams of electrical equipment stored in the memory of the control unit (if any are included), program the anti-theft system, monitor signals in the car circuits in real time.