A modern car is a complex electronic-mechanical complex. Determining a faulty unit or mechanism in such a complex without the help of special diagnostic equipment requires a lot of labor, and in many cases it is completely impossible.

Therefore, almost all produced vehicles equipped with interfaces for connection to diagnostic devices. The most common elements of such interfaces are the OBD2 connector.

What is OBD2 diagnostic connector

A bit of history

For the first time, manufacturers seriously thought about automating car diagnostics in the 70s. It was then that electronic components engine control. They began to be equipped with self-diagnostic systems and diagnostic connectors... By closing the connector contacts, it is possible to diagnose engine control units malfunction using blink codes. With the introduction of personal computer technology, diagnostic devices have been developed to interface connectors with computers.

The emergence of new manufacturers on the car market, and the growing competition have predetermined the need for unification of diagnostic devices. The first manufacturer to seriously tackle this challenge was General Motors, which introduced the ALDL Assembly Line Diagnostic Link, a universal information exchange protocol in 1980.

In the 86th year, the protocol was slightly improved, increasing the volume and speed of information transfer. Already in 1991, the US state of California introduced a regulation according to which all cars sold here followed the OBD1 protocol. It was an acronym for On-Board Diagnostic, that is, on-board diagnostics. It has made life much easier for vehicle service firms. This protocol has not yet regulated the type of connector, its location, error logs.

In 1996, the updated OBD2 protocol has already spread throughout America. Therefore, manufacturers wishing to master the American market were simply forced to comply with it.

Seeing the clear advantage of the process of unification of auto repair and maintenance, the OBD2 standard was extended to all vehicles with gasoline enginessold in Europe since 2000. In 2004, the compulsory OBD2 standard was extended to diesel cars... At the same time, it was supplemented with the Controller Area Network standards for communication buses.

Interface

It is wrong to believe that the OBD2 interface and the OBD2 connector are the same. The concept of an interface includes:

• directly the connector itself, including all electrical connections;
• a system of commands and protocols for information exchange between control units and software-diagnostic complexes;
• standards for the implementation and location of connectors.

The OBD2 connector does not have to be made in a 16-pin trapezoidal design. On many trucks and commercial vehicles they have a different design, but the main transmission buses in them are also unified.

IN passenger carsin mobiles before 2000, the manufacturer could independently determine the shape of the OBD connector. For example, on some MAZDA vehicles, a non-standardized connector was used until 2003.

The exact location of the connector is also not regulated. The standard indicates: within the reach of the driver. More specifically: no further than 1 meter from the steering wheel.

This is often difficult for inexperienced auto electricians. The most common connector locations are:

• near the driver's left knee under dashboard;
• under the ashtray;
• under one of the plugs on the console or under the dashboard (on some VW models);
• under the parking brake lever (often in early OPELs);
• in the armrest (sometimes at Renault).

The exact location of the diagnostic connector for your car can be found in reference books or just google it.

In the practice of an auto electrician, there are cases when a connector was simply cut off or moved to another place during repairs after accidents or modifications to the body or interior. In this case, its restoration is required, guided by the electrical diagram.

Pinout (connection diagram) of OBD2 connector

Connection diagram of the pins of the standard OBD2 16-pin connector used in most modern passenger cars, shown in the figure:

Pin assignment:

1. bus J1850;
2. installed by the manufacturer;
3. weight of cars;
4. signal ground;
5. CAN bus high level;
6. K-Line bus;
7. installed by the manufacturer;
8. installed by the manufacturer;
9. bus J1850;
10. installed by the manufacturer;
11. installed by the manufacturer;
12. installed by the manufacturer;
13. cAN bus J2284;
14. L-Line bus;
15. plus with battery.

The main ones for diagnostics are CAN and K-L-Line buses. In the process diagnostic work they, by exchanging information using the appropriate protocols, interrogate the vehicle's control units, receiving information about errors in the form of unified codes.

In some cases, the diagnostic device cannot communicate with the control units. This is most often associated with a CAN bus malfunction: short circuit or open circuit. Often the CAN bus is closed by faults in control units, for example, ABS. This problem can be solved by disabling individual units.

If the OBD connection is lost, first check whether the native radio is installed on the car. Sometimes a non-standard car radio shorts the K-Line bus.

For greater accuracy, you must turn off the radio tape recorder.

The pins, the purpose of which is determined by the manufacturer, are usually directly connected diagnostic signals specific control units (ABS, airbags sRS security, bodywork, etc.)

Connection via adapters

In the event that a non-standard connector is installed on the car (production of a car before 2000 or freight or commercial vehicles), you can use special adapters or make them yourself.

On the Internet, you can find a circuit for reconnecting the connector pins similar to that shown in the figure:

If the car is in constant operation or for professional work as an auto electrician, it is easier to purchase an adapter (adapter kit).

For the AUTOCOM diagnostic scanner, they look like:

The minimum standard set for passenger cars includes eight adapters. One connector of the adapter is connected to the OBD connector of the car, the other - to the OBD diagnostic cable or directly to the BLUETOOTH ELM 327 scanner.

Not in all cases the use of adapters provides vehicle diagnostics. Some cars do not provide OBD pairing, despite the fact that they can be connected to the OBD connector. This applies more to older cars.

General algorithm for car diagnostics

For diagnostics, you will need an autoscanner, an information display device (laptop, smartphone) and the corresponding software.

The procedure for carrying out diagnostic work:

1. The OBD cable is connected to the diagnostic connector of the car and the autoscanner. When connected, the signal LED on the scanner should light up, indicating that +12 Volt is applied to the scanner. If the +12 Volt pin on the connector is not connected, diagnosis is not possible. You should look for the reason for the lack of voltage at the 16th pin of the diagnostic connector. A possible cause could be a defective fuse. The scanner (if it is not an independent device) connects to the laptop. The computer is loaded with software for diagnostic work.
2. The interface program selects the brand of car, engine, year of manufacture.
3. The ignition is turned on, the end of the auto-diagnostic work of the car is expected (while the lights on the dashboard are blinking).
4. A static error scan is started. During the diagnostic process, the diagnostic process will be indicated on the scanner by blinking LEDs. If this does not happen, most likely the diagnosis will be unsuccessful.
5. At the end of the scan, the program displays error codes. In many programs, they are accompanied by russified decryption, sometimes you should not completely trust them.
6. All error codes should be recorded before deleting them. They can leave, after a while they appear again. This often happens in the ABS system.
7. Delete (or rather rub) errors. This option is available in all scanners. After this operation, inactive errors will be deleted.
8. Switch off ignition. After a couple of minutes, turn on the ignition again. Start the engine, let it run for five minutes, it is better to make a test drive of five hundred meters with the obligatory product of turns to the right and left and braking, reversing, turning on light signals and other options for maximum interrogation of all systems.
9. Re-scan. Compare the newly "stuffed" errors with the previous ones. Remaining errors will remain active and must be resolved.
10. Mute the car.
11. Re-decrypt errors using special programs or the Internet.
12. Switch on the ignition, start the engine, run dynamic engine diagnostics. Most scanners allow in dynamic mode (on a running engine, changing the position of the accelerator pedals, brakes, other controls) to measure the parameters of injection, ignition angle, and others. This information more fully describes the operation of the vehicle. Deciphering the resulting diagrams requires the skills of an auto electrician and a minder.

Video - the process of checking the car through the OBD 2 diagnostic connector using Launch X431:

How to decode error codes

Most OBD error codes are unified, that is, the same decoding corresponds to a specific error code.

The general structure of the error code is:

In some vehicles, the error record has a specific form. It is safer to download error codes on the internet. But to do this for all errors in most cases will be superfluous. You can use special programs such as AUTODATA 4.45 or similar. In addition to decoding, they indicate possible reasons, however, succinctly, and in English.

It is easier, more reliable and more informative to enter in a search engine, for example, "error P1504 Opel Verctra 1998 1.9 B", that is, indicate in abbreviated form all information about the car and the error code. The search result will be fragmentary information on various forums and other sites. You should not immediately blindly follow all the recommendations. But, like the opinion of the audience on a famous program, many of them will be believable. In addition, you can get video and graphic information, sometimes extremely useful.

Pinout OBD-2 (On-Board Diagnostic)- a term that denotes a standard for diagnosing and monitoring the activity of a car engine, some parts of the chassis and other auxiliary devices.

The history of OBD-II began in the middle of the 20th century, when the government of the United States of America unexpectedly discovered that the automotive industry, which they so vehemently support, ultimately causes great damage to the environment, in general, and to humans in particular. Legislation appeared, but no one followed them. However, when the energy crisis came, careless producers had to take at least some measures to save themselves and their consumers. It was against this background that the concept began to develop rapidly, suggesting the standardization of such a device as an OBD-II diagnostic connector.

In fact, the OBD-II pinout is several components of the standardized rules and requirements that automakers must comply with in order for all engine control systems to meet the requirements of federal regulations regarding exhaust gases and smooth functioning of the machine.

The main components of this system, which provide standardization or, in other words, "pinout" of 16-pin OBD-2 connectors for diagnostic operations, are:
Contact 1 (defined by the manufacturer);
Contact 2 - J 1850 bus;
Contact 3 (defined by the manufacturer);
Pin 4 - chassis ground;
Pin 5 is signal ground.
Pin 6 - CAN (direct) J2284;
Contact 7 - ISO 9141 - 2 (K - line);
Pin 8 and 9 (determined by the manufacturer);
Pin 10 - J1850 bus;
Contact 11, 12, 13 (determined by the manufacturer).
Pin 14 - CAN (invested) J2284;
Pin 15 - ISO 9141 - 2 (L - line);
Terminal 16 - battery voltage.

The main function of the OBD-II diagnostic connector is to provide communication between the scanner and control units. An OBD-II connector such as the SAE J1962 DLC should be located approximately in the center of the vehicle, 3 to 18 centimeters from the steering wheel. At the same time, manufacturers have the right to select many contacts themselves. It is very important that the OBD-2 connector (the pinout assumes this) includes grounding and power, allowing the autoscanner to work successfully without connecting any additional power sources.

CAN, J1850 and ISO 9141-2 - these are standards developed by international organizations, and each pin of the OBD-II connector must necessarily comply with one of these documents. For example, the pinout of the OBD-2 connector determines that cars ford brands are connected by pins 2 and 10, and GM cars - only through pin 2. You, in turn, can determine the compatibility of your car using the OBD-2 diagnostic connector.
If the system detects a problem in the composition of the exhaust gases, the inscription will appear Check Engine (call to check the engine) and the light comes on. And you shouldn't panic, your life is safe, and nothing will explode. The OBD-2 connector indicator only warns that the amount of harmful emissions exceeds the norm. You can check how the OBD-II system indicator works by turning on the ignition: when all the indicators on the dashboard light up, the MIL indicator will also light up.
Today, millions of cars are moving on the roads, the owners of which use the OBD-II diagnostic connector, and the attitude towards it is only positive. After all, OBD-2 pinout allows us to breathe cleaner air, as well as without the expensive help of highly qualified specialists with an OBD-II connector to determine the malfunctions of the car with maximum accuracy.

A modern car is saturated with various electronic systems, one of which is the on-board equipment diagnostic system. When building such a system, it uses the obd2 connector, standardized in 1996 and most often used to connect a scanner. It can also be used to analyze such current parameters as voltage, temperature, speed and the like, including directly during the current operation of the car.

Obd2 appearance

According to the requirements of regulatory documents, the obd2 connector socket is located in the passenger compartment next to the steering wheel (distance not less than 18 cm). The electrical characteristics of the connector are sufficient for organizing information exchange using a digital industrial cAN bus (maximum amount nodes - 32, maximum cable length - 35 m).

Connector design

The obd2 connector from a mechanical point of view implements a two-component unbalanced design and contains 16 pins, which are located in two rows. The numbering of contacts in the socket is made from left to right, with the upper row numbered from 1 to 8, and the bottom row from 9 to 16. The plug and socket housings are made of plastic; to increase operational reliability, a thin separator plate is provided in the socket between the rows of contacts.

To automatically set the correct polarity when connecting, the plug and socket housings are trapezoidal in cross section with rounded corners.

The connector pins form two groups according to their purpose. The first of them is standardized, the contacts of the second group can be used by each manufacturer to solve their problems.

Numbering and pin assignment of obd2 connector

Pinout obd2 connector with an indication of the purpose of individual contacts is given in the table.

Self-production of the connecting cable

Need self-made or repair of the connecting cable can occur when the diagnostic tool is connected to the vehicle's on-board computer network. For this, the data given in the table are used. The wires of the cable are connected to the contacts of the plug and socket by soldering in compliance with the usual rules in such cases. After soldering, the contact can be additionally protected with a short cambric.

OBD technology (On-Board Diagnostic - self-diagnosis of on-board equipment) was born in the 50s. last century. The initiator was the US government. Various committees were set up to improve the environment, but no positive results were achieved. And only in 1977 the situation began to change. There was an energy crisis and a decline in production, and this required decisive action from producers to save themselves. The Air Resources Board (ARB) and the Environment Protection Agency (EPA) had to be taken seriously. Against this background, the concept of OBD diagnostics developed.

Many people have the opinion: OBD 2 is a 16-pin connector. If the car is from America, no questions. But with Europe it is a little more complicated. A number of European manufacturers (Ford, VAG, Opel) have been using such a connector since 1995 (recall that there was no EOBD protocol in Europe at that time). Diagnostics of these vehicles is carried out exclusively according to the factory exchange protocols. But there were also such "Europeans" who quite realistically supported the OBD 2 protocol already since 1996, for example, many models of Volvo, SAAB, Jaguar, Porsche. But about the unification of the communication protocol, or, the language in which the control unit and the scanner "speak", it is possible to speak only at the application level. The communication standard was not made uniform. Any of the four common protocols are allowed - SAE J1850 PWM, SAE J 1850 VPW, ISO 9141-2, ISO 14230-4. Recently, another one has been added to these protocols - this is ISO 15765-4, which provides data exchange using the CAN bus.

It should be noted that the presence of a similar connector is not a 100% sign of compatibility with OBD 2. Cars equipped with this system must have a mark on one of the plates in engine compartment or in the accompanying documentation. The most commonly used protocol can be identified by the presence of certain pins on the diagnostic connector. If all pins are present on this connector, refer to the technical documentation for the specific vehicle.

Using EOBD and OBD 2 standards, the diagnostic process electronic systems car is unified, now you can use the same scanner without special adapters to test cars of all brands.

OBD 2 requirements provide:

Standard diagnostic connector

- standard location of the diagnostic connector;

Standard communication protocol between the scanner and the vehicle onboard system diagnostics;

Saving in the ECU memory a frame of parameter values \u200b\u200bwhen an error code appears ("frozen" frame);

Monitoring by on-board diagnostics of components, the failure of which may lead to an increase in toxic emissions into the environment;

Access both specialized and universal scanners to error codes, parameters, "frozen" frames, testing procedures, etc .;

A unified list of terms, abbreviations, definitions used for elements of the electronic systems of the car and error codes.

In accordance with the requirements of OBD 2, the on-board diagnostic system must detect deterioration in the performance of the aftertreatment of toxic emissions. For example, the Check Engine malfunction indicator turns on when the content of CO or CH in toxic emissions at the output of the catalytic converter increases by more than 1.5 times compared to the permissible values. The same procedures apply to other equipment, the failure of which could lead to an increase in toxic emissions.

Engine ECU software modern car multilevel. The first level is software control functions, for example, the implementation of fuel injection. The second level is the software for the electronic backup function of the main control signals in case of failure of the control systems. The third level is on-board self-diagnosis and registration of faults in the main electrical and electronic components and blocks of the vehicle. The fourth level is diagnostics and self-testing in those engine control systems, the malfunction of which can lead to an increase in emissions of harmful substances into the environment. Diagnostics and self-testing in OBD 2 systems is carried out by a fourth level subroutine called Diagnostic Executive (Diagnostic Executive - the diagnostic executive, hereinafter referred to as the DE subroutine). The DE subroutine, using special monitors (emission monitor EMM), monitors up to seven different vehicle systems, the malfunction of which can lead to an increase in emissions. The rest of the sensors and actuators, not included in these seven systems, are controlled by the eighth monitor (comprehensive component monitor - CCM). The DE subroutine is executed in the background, that is, at a time when the on-board computer is not busy performing the main functions - control functions. All eight mentioned mini-programs - monitors constantly monitor the equipment without human intervention.

Each monitor can only perform the drive test once, that is, during the "ignition on - engine running - key off" cycle when certain conditions are met. The criterion at the start of testing can be: time after starting the engine, engine speed, vehicle speed, position throttle etc.

Many tests are performed with a warm engine. Manufacturers set this condition in different ways, for example, for ford cars this means that the engine temperature is above 70 ° C (158 ° F) and has increased by at least 20 ° C (36 ° F) during the trip.

The DE subroutine sets the order and sequence of tests:

Canceled tests - DE subroutine performs some secondary tests (second level software tests) only if the primary tests (first level tests) have passed, otherwise the test does not run, i.e. the test is canceled.

Conflicting tests - Sometimes the same sensors and components must be used by different tests. The DE subroutine does not allow two tests to be run at the same time, delaying the next test until the end of the previous one.

Delayed Tests - Tests and monitors have different priority, the DE routine will delay the execution of a test with a lower priority until it executes a test with a higher priority.

You can also see the pinout of the diagnostic connectors

renault diagnostic connector

opel diagnostic connector

kIA diagnostic connector

Currently, the overwhelming number of foreign cars, as well as cars domestic production have OBD2 diagnostic connector. Through this connector you can connect diagnostic equipment to diagnose your car, as well as connect on-board computers and other devices working through the diagnostic block. Sometimes users have a question about the pinout of diagnostic pads for certain car brands. For your convenience, we offer ready-made adapters for working with various diagnostic pads of cars. However, if you forgot to purchase an adapter for your car, or you needed to make it in emergency conditions, or connect the adapter directly, then in this article you will find information on the pinout of OBD 2 standard pads, as well as Russian and imported cars.

Pinout of the OBD 2 pads (the most common option in foreign cars since 2002, as well as installed in all VAZ cars after 2002):

Contact designations:

7-K-line diagnostics

4/5 - GND protruding pins

16 - adapter power supply + 12V

Pinout of the VAZ pads before 2004:

Contact designations:

M - k-line diagnostics

H or G - adapter power supply + 12V

When connecting the adapter without a block directly to the wires, it is better to take power from the cigarette lighter, since the contact shown in figure H, depending on the model, may not be divorced, and when using the G contact, the gas pump gives very large impulses that can damage the adapter.

(In 99% of cases, you can use the indicated contacts, since damage to the adapters from the fuel pump practically does not occur.)

Connector GAZ (Gazelle) UAZ

Contact designations:

2 - Power adapter + 12V

12 - weight

10 - L-line diagnostics (may not be divorced, usually not used)

11 - K-line diagnostics

Pinout pads Daewoo nexia n100, Matiz, Chevrolet lanos, ZAZ Chans:

Connector M - K - line for diagnostics

Connector A - Ground

Connector H - + 12V (voltage in this connector may not be available on some car models)

Connector G - + 12V from the ignition switch (there may be no voltage when the ignition is on and the engine is not running on some car models

If you are interested in the location of the diagnostic pads in your car, as well as the pinout of diagnostic pads for cars of other brands. Then you can familiarize yourself with them through the systematized catalog of diagnostic adapters. Download pinout of car pads.