Audi A3

Since 1997 of release

Repair and car operation

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

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


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

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

1. System OBD structure includes some the diagnostic devices making monitoring of separate parametres of systems of decrease of 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 gauges and actuation mechanisms, supervises vehicle service cycles, provides storing possibility even failures quickly arising in the course of work and clearing of the block of memory.
Arrangement of a diagnostic socket
2. All models described in the present Management are equipped by system of onboard diagnostics of the second generation (OBD–II). A system Basic element is the onboard processor, more often named the electronic module of management (ЕСМ), or the module of management of functioning of the power unit (РСМ). РСМ is a brain of a control system of the engine. The initial data arrives on the module from various information gauges and other electronic components (switches, the relay etc.) . On the basis of the analysis of the data arriving from information gauges, and according to put in memory of the processor in base parametres, РСМ develops commands on operation of various operating relays and actuation mechanisms, carrying out thereby updating of working parametres of the engine, and providing peak efficiency of its return at the minimum expense of fuel. Data read-out of memory of processor OBD-II is made by means of the special scanner connected to a 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 up the engine”.

3. On service of components of control systems by the engine/decrease of toxicity of the fulfilled gases special guarantee certificates with the prolonged period of validity extend. It is not necessary to undertake attempts of independent performance of problem diagnostics РСМ or replacement of components of system, to an exit of terms of the given obligations, – address to experts of representation car repair shops.
Data on diagnostic devices
Use at diagnostics of considered systems of a digital multimeter with a high impedance essentially raises 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 the several reasons. First, on analogue devices it is difficult enough (at times, 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 high enough impedance (internal resistance of the device makes 10 мОм). As the voltmeter is connected to a checked chain in parallel, accuracy of measurement by that above, than the smaller current will pass through actually device. The given factor is not essential at measurement concerning high values of pressure (9 ё 12), 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 parametres of signals, resistance and pressure in all chains of management is possible by means of a splitter included consistently in a socket of the block of engine management. Thus on the switched off, working engine or during car movement, measurement of parametres of signals on splitter plugs from what the conclusion about possible defects becomes is made.
5. For diagnostics of electronic systems of the engine, automatic transmission, ABS, SRS special diagnostic scanners (Pointer) or testers (Retriever) with a certain cartridge (if it is provided), a universal cable and a socket are applied. Besides, it is possible to apply the expensive specialised automobile diagnostic computer specially developed for full diagnostics of the majority of systems of modern cars to this purpose (for example, ADC2000 firms Launch HiTech, or ESA560, FSA, BEA firms Bosch), or the usual computer with a special cable and the program browser OBD (for example, program Bosch ESI [tronic] in Russian (, ESItronic@msw–, a fax: +49(0) 711 2580488), programs Motor–tester, Mytester, VagCom and VagTool or offered on sites or www.obdы

Universal adapter K-L-line ( (see an illustration in the bottom of page), serves for the coordination of signals of port RS-232 and interfaces ISO-9141 (K–line) and ALDL. The various cables necessary for diagnostics of concrete mark of the car can be connected To adapter sockets. The switches established in the adapter and indication elements allow to choose necessary operating modes and approximately to estimate work of target lines. So, the luminescence of a green light-emitting diode with marks L–line, testifies to connection of line L with the car case. The luminescence of a red light-emitting diode with marks K–line specifies in high potential which blinking of indicators is present during this moment on K.Pri's line 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 in 25-contact COM-port or with the help “Cable RS–232 25 конт. – 9 конт.” In a 9-contact CATFISH-PORT.

Some scanners, besides usual operations of diagnostics, allow, at connection with the personal computer, to unpack stored in memory of the block of management basic schemes of an electric equipment (if are put), to program anticreeping system, to observe signals in car chains in real time.

II for diagnostics of your car you can download the free version of browser OBD 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 up the engine” on a control panel.
7. Firm ToolRama devices can be applied to diagnostics, Inc also, for example. (3500 NW Boca Raton Blvd., Boca Raton, Florida, 33431, USA 1 877 866 5726 – 561 750 4511 – 561 338 8447 FAX):

Tester R000 or scanner P000 with cartridge Т043 or Т053,
Universal cable N000,
Black or white socket N003;
Multiplexer N002A;
Connector N004.
8. The scanner only reads out the malfunctions brought memory and clears memory of malfunctions. Besides the scanner supports only report ISO. The tester in addition can make active and show the current data and supports reports SAE and ISO.

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

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

Reflection of the list of the current given and fixed unstable refusals:

Absolute pressure in the inlet pipeline;
Pressure of the gauge of oxygen;
Temperature of a cooling liquid of the engine;
Settlement loading of the engine;
Speed of the car;
Quality of fuel;
Air expense (on weight);
Ignition advancing;
Position throttle заслонки;
Temperature of soaked up air.

In addition to codes of malfunctions "P0", the device also reflects the expanded codes "P1" for 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 specialised automobile diagnostic device ADC2000:

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

the Two-channel multimeter with digital and graphic data presentation on pressure (150В), frequency (1100кГц), a current (150А).
the Built in scanner for the basic 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 report OBD–II.
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. The information on use of these devices contains in applied documents. About devices you can get acquainted with details on sites,
12. For diagnostics carrying out we recommend to you to address for the qualified help of experts HUNDRED.

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

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

Reading of codes of malfunctions

The information maintenance of categories of a code

Kind P 0 3 8 0 at the left-to the right:

1 category (at the left)

P The power unit
B Body
WITH The chassis

2 category a code Source

0 Standard SAE
1 Expanded – set by the manufacturer

3 category System

0 System as a whole
1 подмешивания air (air/fuel induction)

Fuel injection
3 System of ignition or ignition admissions
4 The additional control of release (auxillary emission control)
5 Speed of the car and management х.х.
6 Entrance and target signals of the block of management
7 Transmission

4,5 categories

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

1. At revealing of the malfunction repeating successively on two trips, РСМ gives out a command on inclusion of the control lamp built in in an instrument guard “Check up the engine”, named 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 lead to damage каталитического the 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 system OBD-II can be made in the various ways. The basic way is reading by means of described above the devices connected to 16-contact socket DLC of system OBD-II. Other ways are possible not on all models. On some models the blinking code (defined by the manufacturer and distinct from codes of standard SAE) can be считан the digital voltmeter or a light-emitting diode. Reading of a code by a lamp “is possible Check up the engine”.
2. Without starting the engine, include ignition, – a control lamp “Check up the engine” should light up, otherwise it is necessary to replace it. Having checked up 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.
Clearing of memory OBD–II
3. At entering of a code of malfunction in memory РСМ on an instrument guard of the car the control lamp “lights up Check up the engine”. The code remains written down in memory of the module.
4. For clearing of memory ЕСМ connect to system the scanner and choose in its menu function CLEARING COEDS (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 safety lock EFI. Alternatively clearing of memory of system can be made by removal of a fusible insert (the main safety lock of system of onboard power supplies), (it is possible to disconnect simply also from the battery a positive wire).

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

5. Track, that memory of system has been cleared before installation on the engine of new components of systems of decrease in toxicity of the fulfilled gases. If before start of system after replacement of the failed information gauge not to make clearing of memory of refusals, РСМ will bring in it a new code of malfunction. Memory clearing allows the processor to make change-over on new parametres. Thus in the first 50 ё 20 minutes after primary start of the engine can take place some infringement of stability of its turns.

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