The idea is not new, but there are many questions. On the one hand, you can remove almost any data, but on the other hand, OBDII is like a patchwork quilt, because... the total number of physical interfaces and protocols will scare anyone. And this is all explained by the fact that by the time the first versions of OBD specifications appeared, most automakers had already managed to develop something of their own. The appearance of the standard, although it brought some order, required the inclusion in the specification of all the interfaces and protocols that existed at that time, well, or almost all of them.

The OBDII connector according to the J1962M standard contains three standard interfaces: MS_CAN, K/L-Line, 1850, plus a battery and two grounds (signal and just ground). This is according to the standard, the remaining 7 out of 16 pins are OEM, that is, each manufacturer uses these pins as he pleases. But standardized outputs often have extended, advanced functions. For example, MS_CAN can be HS_CAN, HS_CAN can be on other pins (not specified by the standard) along with the standard MS_CAN. Pin No. 1 can be: for Ford - SW_CAN, for WAGs - IGN_ON, for KIA - check_engene. Etc. All interfaces were also not stationary in their development: the same K-Line interface was initially unidirectional, now it is bidirectional. The CAN interface’s bandwidth is also growing. In general, the vast majority European cars In the 90s and early 2000s, it was quite possible to diagnose using only K-Line, and most American ones only had SAE1850. Currently, the general vector of development is increasingly wide application CAN, increasing the communication speed. We are increasingly seeing single-wire SW_CAN.

There is an opinion that an English-speaking programmer, sitting on specialized (English-language) forums, delving into the texts of the standards, can, in “maximum 4-5 months,” build a universal engine that can cope with all this diversity. In practice this is not the case. Still, there is a need to sniff every new car., sometimes even the same car, but in different configurations. And it turns out that they claim 800-900 types of supported cars, but in practice 10-20 are actually tested. And this is a system - in the Russian Federation the author knows of at least 3 development teams that followed this thorny path and all with the same disastrous result: you need to sniff/customize every car model, but there are no resources/funds for this. And the reason for this is this: a standard is a standard, and each manufacturer, sometimes forced, and sometimes deliberately, introduces something of its own into its implementation, not described by the standard. In addition, not all data is present on the connector by default. There is data, the appearance of which needs to be initiated (to give a command to one or another unit of the car to transmit the necessary data).

And this is where OBDII bus interpreters come into the picture. This is a microcontroller with a set of interfaces that comply with the J1962M standard, which translates the entire variety of data on different interfaces of diagnostic connectors into a language more convenient for applications, for example, for diagnostic applications. In other words, the entire variety of protocols is now decrypted by the application, no matter what it is running on - on a Windows computer or on a tablet/smartphone. The first mass-produced OBDII interpreter with an open protocol was ELM327. This is an 8-bit microcontroller MicroChip PIC18F2580. Let the reader not be surprised by the fact that this microcontroller is a mass-produced device general use. The firmware is just proprietary and real cost“PIC18F2580+FirmWare” is an impressive $19-24. That is, a scanner made on an “honest” ELM327 chip cannot cost less than 50 evergreen presidents. Why is there such a variety of scanners/adapters on the market with prices starting from 1000 rubles, you ask? And our Chinese friends did their best! How they cloned this chip, etched the crystal layer by layer or sniffed it day and night - we’ll leave it behind the scenes. But the fact remains: clones have appeared on the market (for reference: an 8-bit MicroChip controller now costs less than a dollar in wholesale purchases). Another thing is how correctly these clones work. There is an opinion that “as long as people buy cheap adapters, auto electricians will not be left without work.” That is, a person buys an adapter with the thought of “reloading or adjusting something,” but the result he gets is different, well, that is, not the one he expected. Well, for example, suddenly the multimedia system starts blinking with all its lights, or an error pops up, or even a box in emergency mode passes. And it’s good if there are no serious consequences - in most cases, a specialist with professional equipment will cure iron horse. But it also happens differently. Several factors can be mixed up here: the wrong adapter (clone), the wrong software, the wrong combination of adapter + software, and “crooked” hands can also play a role. I note that an adapter on an honest chip from a manufacturer with the right software will not lead to disastrous results, at least the author is not aware of such cases.
What can you do with such an adapter? Well, probably the most common case is to put it in the glove compartment “just in case.” Look and reset the error as soon as it appears. Reset the odometer before selling the car, or vice versa, “wind up” if you are a hired driver. Enable any option in the car that is disabled by default, but official dealer this service is paid. Updating firmware and reconfiguring electronic units will still be left to specialists, but most adapters allow this too. Some will simply like to have more information about the operating parameters of the engine and other systems in the form of beautiful graphics on a tablet or smartphone. For some reason, taxi drivers who have an Android tablet installed in front of them are often found on the road. dashboard and completely covers it, so: this tablet is most likely connected to such an adapter via Bluetooth or Wi-Fi. There is more whole line applications, this is the use of such an adapter in conjunction with a telematics device (tracker) or alarm system. Connecting to the diagnostic connector using such an adapter allows you to easily obtain the data necessary for monitoring. In most cases, this method costs the developer less, and the installation itself is simpler, because the need to install various sensors disappears; everything (or almost everything) can be removed from OBDII.
Another thing is that the capabilities of the chip are currently no longer sufficient for use in modern cars mobile phones Somewhere in the mid-2000s, communication speeds on the CAN bus increased, and SW_CAN appeared. But the most important thing: the length (number of characters) in code words has increased. And if in hardware it is possible, through a relay or a banal toggle switch, to stick crutches to the ELM327 that will allow you to work with MS and HS and even with SW CAN releases, then for long code words computing power PIC18F2580 with its 4 MIPS is clearly not enough. By the way, latest version ELM327 (V1.4) dates back to 2009. And this chip can only be used without “crutches” for cars manufactured before the mid-2000s. So what to do? Strangely enough, there is a way out, and more than one.
CAN-LOG, also an interpreter, but not a full set of OBDII interfaces, but two CAN buses. It turns out that this is enough to remove all necessary information. True, not all cars have both CAN buses connected to diagnostic connector. This means you will have to connect under the instrument panel. And this is not always acceptable for reasons of maintaining the warranty, although there is an option for wirelessly retrieving information from the bus, but this is even more expensive, and the reliability of the collected data is not 100%. Can be used as ready-made device, connecting it via UART or RS232, or just a chip, integrating it onto a device board with a small number of discrete components. The cost of the device is, of course, higher than the cost of an authentic ELM327, but this is compensated by a huge list of supported cars and functions. Moreover, the list of supported cars includes not only cars, but also trucks, construction, road and agricultural equipment. CAN-LOG works slightly differently than the ELM327 and its clones. When connecting to the car tires, you must select and set the program number, corresponding to the vehicle. And this is convenient, because... the developer does not need to delve into all the variety of protocols. (In the ELM327, car selection and chip fine-tuning are left to the application).
There are other solutions that allow you to easily and elegantly remove data from the diagnostic connector. Well, the question of whether it is possible to tame the standard diagnostic connector and how, each developer will decide for himself. For a fleet of cars of the same brand, you can try to write your own software, unless of course the manufacturer closes the protocols. And if the telematics device will be installed on different models, then it makes more sense to use one of the OBDII interpreters.

The diagnostic connector is a standardized SAE J1962 trapezoidal connector with sixteen contacts arranged in two rows).

According to the standard, the OBD2 connector must be located inside the car (most often located in the area of ​​the steering column). The location of the OBD-1 connector is not strictly regulated and it can even be located in engine compartment.

Using the connector you can determine which OBD2 protocols are supported in your car. Each protocol uses specific connector pins. This information will be useful to you when choosing an adapter.

Pinout (pin assignment) of OBD2 connector

1	OEM (manufacturer's protocol).
2	Bus + (Bus positive Line). SAE-J1850 PWM, SAE-1850 VPW.
3	-
4	Chassis Ground.
5	Signal Ground.
6	CAN-High speed line CAN bus Highspeed (ISO 15765-4, SAE-J2284).
7	K-Line (ISO 9141-2 and ISO 14230).
8	-
9	Line CAN-Low, low-speed CAN Lowspeed bus.
10	Bus - (Bus negative Line). SAE-J1850 PWM, SAE-1850 VPW.
11	-
12	-
13	-
14	CAN-Low line high speed tire CAN Highspeed (ISO 15765-4, SAE-J2284).
15	L-Line (ISO 9141-2 and ISO 14230).
16	Power supply +12V from the battery (Battery Power).

Pins 3, 8, 11, 12, 13 are not defined by the standard.

Determining the OBD2 protocol used in the car

The standard regulates 5 protocols, but most often only one is used. The table will help you determine the protocol based on the contacts involved in the connector.

Protocol	con. 2	con. 6	con. 7	con. 10	con. 14	con. 15
ISO 9141-2			+			+
ISO 14230 Keyword Protocol 2000			+			+
ISO 15765-4 CAN (Controller Area Network)		+			+
SAE J1850 PWM	+			+
SAE J1850 VPW	+

In the PWM and VPW protocols there is no 7 (K-Line) pin, in ISO there is no 2 and/or 10 pin.

You can also see the pinout 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 that work through the diagnostic connector. Sometimes users have questions about the pinout of diagnostic blocks for certain car brands. For your convenience, we offer ready-made adapters for working with various diagnostic plugs on cars. However, if you forgot to purchase an adapter for your car, or you needed to make it in an emergency, or connect the adapter directly, then in this article you will find information about the pinout of OBD 2 standard blocks, as well as Russian and foreign-made cars.

Pinout of the OBD 2 block (the most common option in foreign cars since 2002, and is also installed in all VAZ cars after 2002):

Contact designations:

7-K diagnostic line

4/5 - GND protruding pins

16 - adapter power supply +12V

Pinout of the VAZ block before 2004:

Contact designations:

M - k-line diagnostics

H or G - adapter power supply +12V

When connecting an 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 routed, and when using the G contact, the fuel 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 - mass

10 - L-diagnostic line (may not be routed, as a rule not used)

11 - K-line diagnostics

Pinout of the block 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 block in your car, as well as the pinout of diagnostic blocks for cars of other brands. Then you can familiarize yourself with them through a systematic catalog of diagnostic adapters. Download pinout of car brake pads.

The pinout of the OBD 2 connector will allow the car owner to correctly connect the contacts of the block for diagnostics vehicle. A scanner or personal computer (PC) is connected to this plug to check the car.

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Description and features of OBD 2

The standard OBD 2 vehicle diagnostic system includes the X1234 code structure.

Each character here has its own meaning:

1. X - the element is the only letter and allows you to find out the type of car malfunction. May not work correctly power unit, transmission, sensors, controllers, electronic modules, etc.
2. 1 - general OBD class code. Depending on the car, it is sometimes an additional manufacturer code.
3. 2 - using the symbol, the car owner will be able to clarify the location of the problem. For example, this could be the ignition system, battery power supply ( battery), additional power lines, etc.
4. 3 and 4 - determine serial number malfunctions.

The main feature of the block is the presence of a power output from the vehicle's electrical network, which makes it possible to use scanners that do not have built-in power lines. Initially, diagnostic protocols were used to obtain data about the occurrence of problems in the operation of systems. Pads in modern cars allow consumers to receive more information about errors. This is ensured by the connection of diagnostic scanners and devices with electronic modules in the car.

Depending on the adapter manufacturer, the device may belong, for example, to the following international classes:

• SAE J1850;
• SAE J1962;
• ISO 9141-2.

The World of Matizov channel spoke in detail about the purpose of diagnostic pads and their use.

Where is OBD 2 located?

The location of the OBD 2 block is always indicated in the service manual, so it is better to clarify this point in the documentation.

The different positions of the diagnostic plug in a car are due to the fact that vehicle manufacturers do not use a single standard regarding the installation of pads. If the device is classified as J1962, it must be installed within a radius of 18 cm from the steering column. Manufacturers actually do not follow this rule.

The device location may be as follows:

1. In a special slot in the lower casing of the instrument cluster. It can be seen in the center console in the driver's left knee area.
2. Under the ashtray, which is usually located in the center of the console and instrument cluster. The connector is often installed in this place by French car manufacturers - Peugeot, Citroen, Renault.
3. Under the plastic plugs located on the bottom of the instrument cluster. In this place, the pads are usually installed by the VAG manufacturer - Audi, Volkswagen, etc. cars.
4. On the rear of the center console, in the area where the glove compartment housing is installed. This location is typical for some VAZ cars.
5. In the handle area hand brake, under the plastic of the center console. This situation is typical for Opel cars.
6. At the bottom of the armrest niche.
7. In the engine compartment, next to the engine shield. This is where the connector is installed by Korean and Japanese manufacturers.

If the car has a significant mileage, then the installation location may be different. Sometimes when electrical faults or damage to the circuits, car owners remove the connector.

User Ivan Matieshin, using the example of a Lada Granta car, showed where the OBD 2 diagnostic output is installed.

Types of connectors

In modern vehicles, two types of diagnostic sockets can be used - classes A or B. Both connectors are equipped with 16-pin outputs, eight contacts in each row. The contact elements are numbered from left to right, respectively, components numbered 1–8 are located at the top, and 9–16 at the bottom. The outer part of the body of the diagnostic block is made in the form of a trapezoid and is characterized by rounded shapes, which makes it possible to connect an adapter.

The main difference between different types The connectors are located in guide grooves located in the center.

Photo gallery

Photos of potential locations of diagnostic connectors:

Location of the connector in the glove compartment of the car Diagnostic output under the center console of the car Location of the block under the ashtray in the cabin

OBD 2 pinout

Connection diagram of contact elements to the diagnostic block:

1. Backup contact. Depending on the manufacturer, any signal can be output to it. He is appointed by the car developer.
2. Pin K. Used to send different parameters to the control unit. In many cars it is designated as the J1850 tire.
3. A backup contact assigned by the vehicle manufacturer.
4. "Ground" of the diagnostic block connected to the vehicle body.
5. Ground of the diagnostic adapter signal.
6. Contact element for direct connection of the J2284 digital CAN interface.
7. Contact for connecting channel K in accordance with international standard ISO 9141-2.
8. Reserve contact element, assigned by the vehicle manufacturer.
9. Spare contact.
10. Pin required for connection to J1850 class bus.
11. The purpose of this contact is determined by the machine manufacturer.
12. Appointed by the car developer.
13. Reserve pin assigned by the manufacturer.
14. Additional contact element for connecting the digital CAN interface J2284.
15. Pin for channel L, designed for connection in accordance with ISO 9141-2 standard.
16. A positive contact for connecting the car's electrical system voltage, rated for 12 volts.

As an example of a factory pinout of a block, you can use the Hyundai Sonata. In these models, the first contact of the connector is intended to receive signals from the control module anti-lock braking system. Pin number 13 is used to read pulses from the ECU ( electronic unit controls), as well as airbag controllers.

Pinout types may vary depending on the protocol class:

1. If the car uses the ISO9141-2 standard, then this protocol is activated by using pin 7. Pins numbered two and ten are not used and are inactive. To send information, contact elements 4, 5, 7 and 16 are used. Depending on the car, contact 15 can be used for this task.
2. If the car implements the SAE J1850 type VPW protocol, then the second, fourth, fifth and sixteenth pins are used in the connector. Such pads are usually equipped in vehicles from General Motors European and American production.
3. It is possible to use the J1850 protocol in PWM mode. This application involves the additional use of the tenth pin. A similar type of connector is installed on Ford cars. Regardless of the type of output, the seventh pin is not used.

The MotorState channel spoke in detail about OBD pinout 2 diagnostic connectors for cars.

Diagnostics via OBD 2

The verification procedure is carried out as follows:

1. Depending on the vehicle, the diagnostic process can be carried out with the ignition off or on. This moment This needs to be clarified in the service manual. Before starting, the ignition procedure in the car is turned off or on.
2. The program is launched on the computer to check.
3. Connecting diagnostic equipment to the connector. If this is a scanner, then the block with the wire from it needs to be inserted into the plug. When using a PC, one end of the adapter is installed in the USB output of the computer, and the other is connected to the connector.
4. You need to wait until the program detects the block after synchronization. If this does not happen, you should manually go to the control menu and select the option to search for new devices.
5. The diagnostic procedure starts on the computer. Depending on the software, the user may have the option to choose the right tool checks. Some programs support separate engine diagnostics, transmission unit, electrical networks and other nodes.
6. After completing the test procedure, fault codes will appear on the PC screen. These errors must be deciphered in order to accurately determine the type of failure. In accordance with the data received, the vehicle is repaired.

Video “How to diagnose a car using OBD 2?”

The SUPER ALI channel showed the process of testing vehicle systems using a special scanner connected to the OBD 2 connector.

OBD technology (On-Board Diagnostic - self-diagnosis of on-board equipment) originated back in the 50s. last century. The initiator was the US government. Various committees were created to improve the environment, but no positive results were achieved. It was only in 1977 that the situation began to change. An energy crisis and a decline in production set in, and this required manufacturers to take decisive action to save themselves. The Air Resources Board (ARB) and the Environmental 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, there are no questions. But with Europe it’s a little more complicated. Row European manufacturers(Ford, VAG, Opel) have been using this connector since 1995 (remember that at that time there was no EOBD protocol in Europe). Diagnostics of these cars is carried out exclusively according to factory exchange protocols. But there were also “Europeans” who quite realistically supported OBD protocol 2 already since 1996, for example many Volvo models, SAAB , Jaguar , Porsche . But the unification of the communication protocol, or the language in which the control unit and scanner “speak,” can only be discussed at the application level. The communication standard was not made uniform. It is allowed to use any of the four common protocols - SAE J1850 PWM, SAE J 1850 VPW, ISO 9141-2, ISO 14230-4. Recently, one more protocol has been added to these protocols - 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 diagnostic connector. If all pins are present on this connector, please contact technical documentation for a specific car.

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

The OBD 2 standard requirements include:

Standard diagnostic connector

- standard placement of the diagnostic connector;

Standard protocol for data exchange between the scanner and the vehicle on-board system diagnostics;

Saving a frame of parameter values ​​in the ECU memory when an error code appears (“frozen” frame);

Monitoring by on-board diagnostic tools of components, the failure of which could lead to an increase in toxic emissions in environment;

Access to 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 vehicle electronic systems and error codes.

In accordance with OBD 2 requirements, the on-board diagnostic system must detect deterioration in the performance of toxic emission after-treatment devices. For example, the indicator faults Check Engine turns on when the CO or CH content in toxic emissions at the outlet increases catalytic converter more than 1.5 times compared to acceptable values. The same procedures apply to other equipment whose malfunction may result in increased toxic emissions.

Engine ECU Software modern car multi-level. The first level is the software of 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 the event of a failure of control systems. The third level is on-board self-diagnosis and registration of faults in the main electrical and electronic components and units of the vehicle. The fourth level is diagnostics and self-testing in those engine control systems, a malfunction of which can lead to an increase in emissions 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, hereinafter referred to as the DE subroutine). The DE subroutine, using special monitors (emission monitor EMM), controls up to seven various systems vehicles, malfunction of which can lead to increased toxic emissions. Other sensors and actuators, not included in these seven systems, are controlled by the eighth monitor (comprehensive component monitor - CCM). The DE subroutine runs in the background, i.e., while on-board computer not busy performing basic functions - management functions. All eight mentioned mini-programs - monitors - constantly monitor the equipment without human intervention.

Each monitor can perform testing only once during a trip, that is, during the “ignition key on - engine running - key off” cycle, if certain conditions are met. The criteria for starting testing can be: time after starting the engine, engine speed, vehicle speed, position throttle valve etc.

Many tests are performed with the engine warm. Manufacturers set this condition differently, 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 establishes the order and sequence of tests:

Canceled Tests - The DE routine performs some secondary tests (tests by software second level) only if the primary (first level tests) have been passed, otherwise the test is not performed, i.e. the test is canceled.

Conflicting tests - sometimes the same sensors and components must be used different tests. The DE subroutine does not allow two tests to be carried out simultaneously, delaying the next test until the end of the previous one.

Delayed tests - tests and monitors have different priorities, the DE routine will delay the test execution with more low priority until it executes a higher priority test.