Audi A3

since 1997 of release

Repair and car operation

Audi A3
+ Maintenance instruction
+ Current leaving and service
+ Engine
+ Systems of cooling, heating
+ the Power supply system and production of the fulfilled gases
- Engine electric equipment
   - System of electronic control by ignition and injection
      Self-diagnostics of systems of electronic control of the second generation of OBD II
      Ignition system
      Checks of system of ignition and injection
      Spark plugs
   + charge and start Systems
+ Manual box of gear shifting
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Elektroskhema


Self-diagnostics of systems of electronic control of the second generation of OBD II


The description of elements of system of electronic control is provided by ignition and injection in the section of the Power supply system and production of the fulfilled gases.

(In case of the equipment of your OBD II car on шильде under a cowl there should be a record "OBD II compliant" and there should be a 16-contact socket. As a rule OBD II are equipped models, since 1996 of release).

1. The structure of OBD system includes some diagnostic devices making monitoring of separate parameters of systems of decrease in toxicity and fixing revealed refusals in memory of the onboard processor in the form of individual codes of malfunctions. The system makes also check of sensors and actuation mechanisms, supervises vehicle service cycles, provides storing possibility even failures quickly arising in the course of work and cleaning of the block of memory.
Arrangement of the diagnostic socket
2. All models described in the real Management are equipped with system of onboard diagnostics of the second generation (OBD–II). A basic element of system is the onboard processor more often called by the electronic module of management (ESM), or the module of management of functioning of the power unit (RSM). RSM is a brain of a control system of the engine. Basic data arrive on the module from various information sensors and other electronic components (switches, the relay etc.) . On the basis of the analysis of data arriving from information sensors, and according to put in memory of the processor in base parameters, RSM develops commands for operation of various operating relays and actuation mechanisms, carrying out thereby adjustment of working parameters of the engine, and providing maximum efficiency of its return at the minimum fuel consumption. Data read-out of memory of the OBD-II processor is made by means of the special scanner connected to the 16-contact diagnostic socket of reading of a database (DLC), located under the control panel a heater.


On some models reading written down in memory of system of self-diagnostics of codes of malfunctions can be made by means of a lamp “Check the engine”.

3. On service of components of control systems of engine/decrease in toxicity of the fulfilled gases special guarantee certificates with the prolonged validity period extend. It is not necessary to undertake attempts of independent performance of problem diagnostics of RSM or replacement of components of system, to an exit of terms of these obligations, – address to specialists of representation car repair shops.
Data on diagnostic devices
Use at diagnostics of considered systems of a digital multimeter with a high impedance essentially increases accuracy of made measurements
4. Check of serviceability of functioning of components of systems of injection and decrease in toxicity of the fulfilled gases is made by means of a universal digital measuring instrument (multimeter). Use of a digital measuring instrument preferably 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 in the structure electronic components, such accuracy takes on special significance. The second, the reason that fact is not less important that the internal contour of a digital multimeter, has rather high impedance (internal resistance of the device makes 10 megohms). As the voltmeter is connected to a checked chain in parallel, accuracy of measurement by that is higher, than the smaller current will pass through actually device. This factor is not essential at measurement of rather high values of tension (9 ё 12 In), however there is defining at diagnostics of elements giving out low-voltage signals, such, as, for example, a l-probe where it is a question of measurement of shares of volt.

Parallel supervision of parameters of signals, resistance and tension in all chains of management is possible by means of a splitter included consistently in the socket of the control unit by the engine. Thus on the switched-off, working engine or during car movement, measurement of parameters of signals on splitter plugs from what the conclusion about possible defects is drawn is made.
5. Special diagnostic scanners (Pointer) or testers (Retriever) are applied to diagnostics of electronic systems of the engine, automatic transmission, ABS, SRS with a certain cartridge (if it is provided), a universal cable and the socket. Besides, it is possible to apply the expensive specialized automobile diagnostic computer which has been specially developed for complete diagnostics of the majority of systems of modern cars to this purpose (for example, Launch HiTech firm ADC2000, or ESA560, FSA, Bosch firm BEA), or the ordinary computer with a special cable and the program OBD browser (for example, the Bosch ESI program [tronic] in Russian (, ESItronic@msw–, a fax: +49 (0) 711 2580488), the Motor-tester, Mytester, VagCom and VagTool programs or offered on sites or www.obd–

The universal K-L-line adapter ( (see an illustration in the bottom of page), serves for coordination of signals of RS-232 port and ISO-9141 (K-line) and ALDL interfaces. The various cables necessary for diagnostics of concrete make of the car can be connected to sockets of the adapter. The switches established in the adapter and elements of indication allow to choose necessary operating modes and approximately to estimate work of target lines. So, the luminescence of a green light-emitting diode with L–line marking, testifies to connection of the line L with the car case. The luminescence of a red light-emitting diode with marking of K-line indicates high potential which blinking of indicators is present during this moment on K.Pri's lines of the established communication with the car can be imperceptible for an eye because of high speed of an exchange. Connection to the computer is made directly to the 25-contact COM port or with the help “RS–232 25 cable Kont. – 9 Kont.” in a 9-contact CATFISH port.

Some scanners, besides usual operations of diagnostics, allow, at connection with the personal computer, to unpack being stored in memory of the control unit schematic diagrams of electric equipment (if are put), to program anticreeping system, to observe signals in car chains in real time.

For diagnostics of your car you can download the free version of a browser of OBD II from our site
6. Cчитывание written down in memory of system of self-diagnostics of codes of malfunctions, on some cars, can be made also on the indicator “check the engine” on a control panel.
7. Firm ToolRama, Inc devices can be also applied to diagnostics, for example. (3500 NW Boca Raton Blvd., Boca Raton, Florida, 33431, USA 1 877 866 5726-561 750 4511-561 338 8447 FAX):

tester of R000 or the P000 scanner with cartridge Т043 or Т053,
universal cable of N000,
black or white N003 socket;
N002A multiplexer;
N004 connector.
8. The scanner only reads out the malfunctions brought memory and clears memory of malfunctions. Besides the scanner supports only the ISO protocol. The tester in addition can make active and show the current data and supports the SAE and ISO protocols.

All cartridges for a tester can be used and in the scanner. Thus functions will be limited only to reading and memory cleaning.
9. For the majority of cars of release since 1996 supporting the SAE/ISO 9141 OBD II protocol OBD II cartridge carrying out the following functions can be used:

· Reading and removal of codes of malfunctions of OBD II. Reflection of results of tests of the sensor of oxygen.
· Continuous control of systems of ignition, injection and components.

· Reflection of the list of the current data and the fixed unstable refusals:

Absolute pressure in the inlet pipeline;
Tension of the sensor of oxygen;
Temperature of cooling liquid of the engine;
Settlement loading of the engine;
Speed of the car;
Quality of fuel;
Consumption of air (on weight);
Ignition advancing;
Provision of a butterfly valve;
Temperature of soaked-up air.

In addition to codes of malfunctions of "P0", the device also reflects expanded codes of "P1" for the models Acura, Audi, BMW, Chrysler, Dodge, FORD, Geo, GM, Honda, Hyundai, Infinity, Kia, Lexus, Lincoln, Mercury, Mazda, Mercedes, Mitsubishi, Nissan, Porsche, Saturn, SEAT, Skoda, Subaru, Suzuki, Toyota, Volvo, VW.
10. Features of the specialized automobile diagnostic ADC2000 device:

· The built-in 4-channel oscilloscope with standard preset for 19 sensors.
· The analyzer of system of ignition for check primary and secondary chains (with tension to 100кВ) on systems with the distributor or separate coils of ignition – with control of time of burning, peak value of tension, a corner of an advancing of ignition, a current, and turns.

· A two-channel multimeter with digital and graphic data presentation on tension (150В), frequency (1100кГц), to a current (150А).
· The built-in scanner for the main systems on cars: VAG, MB, BMW, Volvo, Toyota/Lexus, Mitsubishi, Nissan, Honda, Mazda, GM, Ford, Chrysler, Daewoo, Hyundai, Kia, Samsung, and also on cars supporting the OBD-II protocol.
· Cartridges are not required – you can execute updating of programs of the device, having downloaded necessary updatings from the Internet.
· The software for communication with the personal computer.
11. Information on use of these devices contains in enclosed documents. About devices you can get acquainted with details on sites,
12. For carrying out diagnostics we recommend to you to address for the qualified help of experts HUNDRED.

ISO 9141–2 (Chrysler, European and majority of Asian models) Contacts 4, 5, 7, 15, 16

conclusion No.
Connection with the case
The case – an alarm conclusion
Line K, ISO 9141
Line L, ISO 9141
Battery plus through a safety lock. Energized, at any position of the lock of ignition

Reading of codes of malfunctions

Information contents of categories of a code

Type of P 0 3 8 0 from left to right:

1 category (at the left)

P power unit
B body
With chassis

2 category code Source

0 standard SAE
1 the expanded – set by the producer

3 category System

0 system as a whole
1 podmeshivaniye of air (air/fuel induction)

fuel injection
3 system of ignition or ignition admissions
4 additional control of release (auxillary emission control)
5 speed of the car and management х.х.
6 entrance and target signals of the control unit
7 transmission

4,5 categories

Serial number of malfunction of a component or chain (00–99)

1. At detection of the malfunction repeating in a row on two trips, RSM gives out command for inclusion of the control lamp built in in an instrument guard “Check the engine”, called also the indicator of refusals. The lamp will continue to burn until memory of system of self-diagnostics will not be cleared of the codes of the revealed malfunctions brought in it (address to Specifications). If the lamp blinks, – the malfunction, capable to bring to damage of the catalytic converter is registered. It is necessary to lower speed while the lamp will not go out or it is not necessary to burn constantly. Reading of codes of malfunctions in OBD-II system can be made in the various ways. The main way is reading by means of described above the devices connected to the 16-contact DLC socket of OBD-II system. Other ways are possible not on all models. On some models the blinking code (defined by the producer and distinct from SAE standard codes) can be считан the digital voltmeter or a light-emitting diode. Reading of a code by a lamp “Is possible check the engine”.
2. Without starting the engine, include ignition, – a control lamp “Check the engine” should light up, otherwise it is necessary to replace it. Having checked serviceability of a condition of a lamp, again switch off ignition.

If memory of system is pure, the control lamp will not join.

Engine start automatically interrupts access to diagnostics system.
Cleaning of memory of OBD-II
3. When entering a code of malfunction in memory of RSM on an instrument guard of the car the control lamp “Lights up check the engine”. The code remains written down in memory of the module.
4. For cleaning of memory of ESM connect to system the scanner and choose in its menu the CLEARING COEDS function (Removal of codes). Further follow the instructions highlighted on the device, or at once for 30 seconds take from the nest in the assembly block EFI safety lock. Alternatively cleaning of memory of system can be made by a way of removal of a fusible insert (the main safety lock of system of onboard power supply), (it is possible to disconnect also simply from the battery a positive wire).

It is not desirable to make cleaning of memory of OBD by a detachment of a negative wire from the battery as it will lead to deleting of adjusting parameters of the engine and violation of stability of its turns for short time after primary start.
If the stereosystem established on the car is equipped with a security code before disconnecting the battery make sure that have the correct combination for audiosystem input in action!
Battery shutdown also leads to removal of settings of the receiver on favourite radio stations. Attention: In order to avoid ESM damage its shutdown and connection should be made only at the switched-off ignition!

5. Track, that memory of system was cleared before installation on the engine of new components of systems of decrease in toxicity of the fulfilled gases. If before system start after replacement of the failed information sensor not to make cleaning of memory of refusals, RSM will bring in it a new code of malfunction. Cleaning of memory allows the processor to make change-over on new parameters. Thus in the first 50 ё 20 minutes after primary start of the engine can take place some violation of stability of its turns.