Why do car diagnostics? The ability to comprehensively assess the condition of the car

24.04.2019

Brake system

The main condition for a long and trouble-free operation of the car is the timely elimination of problems as they arise. And if earlier definition malfunctions took a long time and had low accuracy, the use of new technologies made it possible to quickly diagnose and.
What is computerized vehicle diagnostics?

Motorists often do not represent the essence and features of such checks. But here everything is simple. This is a test of electronic components and executive elements of the car that affect the functioning of the on-board system and the car as a whole. With the help of computer diagnostics, malfunctions of nodes are determined for further registration of a special error map and correction of current malfunctions.

IN onboard systems self-diagnostic systems are provided. They carry out continuous testing of the main systems during engine start-up and during operation. power node. Thanks to the information received, the driver learns in a timely manner about current malfunctions and defects in the car.
To check and read the ECU in the car there is a diagnostic connector. Special diagnostic and instrumentation devices are connected to it. The use of products is the ability to accurately diagnose a malfunction and eliminate it.

When to get diagnosed?

Car enthusiasts avoid costs, so diagnosis often comes down to applying "grandfather" methods or ignoring the problem. This approach leads to even more damage and costs in the future. To avoid problems, it is worth responding to the following symptoms of a malfunction:

growth in gasoline consumption diesel fuel) by car;
failure of the accelerator pedal. When pressed, instead of speeding up, it slows down;
the appearance of black and white exhausts;
the occurrence of noise and knocks;
increase in the warm-up time of the power unit (in comparison with previous indicators);
reduction of power loss of the power unit.

The symptoms described above indicate obvious problems with the engine or other components of the car, which are determined by conducting computer diagnostics. Checking will not be superfluous in the following cases:

when buying from a private seller;
when preparing the car for sale on your own. Carrying out diagnostics is a chance to accurately calculate the cost of a car;
in a situation where the machine is operated for a long time without repair;
in cases where the car is used in extreme conditions(travel out of town, long journey, adverse weather conditions, etc.).

Diagnostic methods

Video: How computer diagnostics for cars are used

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Before starting the repair, the master determines which mechanism is faulty. This requirement is relevant for all studied mechanisms, be it an engine or a suspension. Today, diagnosis is carried out in three ways:

with the help of human senses, such as smell, hearing and vision;
inspection of the car, the use of instruments and the measurement of key parameters;
conducting electronic (computer) diagnostics.

In practice, all of the above methods are used. The difference is only in the duration and accuracy of the procedure. The first method is the simplest, but not very accurate. The second is accurate, but involves time. The ideal option is computer diagnostics of the car. Its essence is in scanning the nodes controlled by the microprocessor.

Verification Features

New car models have an ECU (electronic control unit) that captures current errors and notifies the driver about problems with a particular node. All malfunctions are detected using special complexes. The service is carried out:

car engine diagnostics, checking the operation of all sensors, controllers and systems;
diagnostics of the correct operation of the crank group and the ECU.

Auto diagnostic software

As soon as all checks are completed, current faults appear on the monitor screen. Next, the program reconfigures the ECU (if there are violations). If the problem is a fuel system failure, then the program determines the repair option.
In addition to the engine, fuel system and cooling system, other systems are checked - the gearbox and running components of the car. When the probability of missing something is minimal. The specialist accurately determines the malfunction, which saves time on finding the problem and money on repairing serviceable parts.

Diagnostic nuances

Video: Computer diagnostics of the car ELM327 (Part 1)

A popular check is engine diagnostics, for which a scanner and a motor tester are used. First, nodes are scanned - electronic diagnostics. The scanner is a personal computer (or laptop), which is connected via the diagnostic connector and reads error codes. A feature of such a device is assistance in controlling mechanisms and decoding signals sent from microprocessor sensors.
In practice, scanning is not enough to determine the fault. To get accurate results, a motor tester is used - a multi-channel oscilloscope. The task of the device is to measure incoming on-board computer signals, displaying waveforms and other data on the screen. Additional information allows you to draw accurate conclusions about the malfunction and decide what to do next.
The equipment described above is available in two types:

motor-testers of a stationary type - devices designed for multilateral diagnostics vehicle. Such OBD-II systems- only a small part of the gas analyzer system, taking compression parameters, pressure in the fuel system, and so on;
dealer scanners (specialized devices) are digital products with multifunctionality. It is essentially a combination of a small computer, an oscilloscope, and a multimeter. The cost of a specialized device exceeds 2-3 thousand dollars, so you can only find it at a specialized service station.

Despite the accuracy and simplicity, computer diagnostics of a car takes some time. The problem cannot be identified immediately. The average duration of the tests is 20-30 minutes, because the specialists at the service station not only read error codes, but also decipher the ECU readings.

Stages of work on computer diagnostics of a car

Computer diagnostics car engine

Computer diagnostics includes testing of vehicle electronics and units responsible for the operation of the main components of the vehicle - engine, suspension, cruise control, transmission, navigation, dashboard and so on. The work takes place in several stages:

Vehicle components are checked using the available diagnostic tools, basic data is taken from the vehicle components, and errors are read. At this stage, the service station employee must correctly decipher the scanner readings and draw preliminary conclusions about the malfunction;
At the second stage, additional analog testing is done. The electrical part of the car is checked - wires, batteries, contact connections, generator. The master determines whether the system is healthy or not. Otherwise, the rest of the data won't matter;
Vehicle parameters are checked online. The name of the option is "Data Stream". Information on the flow - a chance to check the signals from the executive bodies and other elements. In this mode, the main parameters are visible on the screen of the testing device - fuel injection, sensors, XX mode, and so on;
The analysis of the data obtained during the verification process is carried out. As already mentioned, the scanner produces the main waveforms, which should be compared with typical ones for each of the cars. Usually a qualified craftsman has all this information at hand;
Errors recorded in the controller memory are erased. This is followed by a re-initialization. In some cases, it is necessary to perform repeated work on initialization (if the main parameters were knocked down).

Conclusion

Computer diagnostics of the car - the ability to identify a malfunction (at an early stage) and eliminate it. Savings in this business often lead to the failure of expensive components and, as a result, high costs.

Technical awareness is like a traveler's compass. This is the same Glonass, GPS. Without knowing the basics of the subject, you will not move a single step. How and where to go? These are the questions that have to be addressed almost constantly. Any car requires knowledge and experience. Not everyone wants to use them. It's all about the possibilities. The critical situation, however, does not pardon anyone. The road is the road. It may happen that there is nothing to hope for. You have to take your head and hands. It is not superfluous to equip them with something. In advance!

Introduction to the topic

Car diagnostics is not an easy process. Accessible, but requires training. In addition to desire and opportunity, and even a penchant for technology, a certain theoretical and practical support is needed. Namely:

knowledge in the motor system (nodes, functions, common causes of failures, minor repairs);
the concept of electrical equipment (equipment, purpose of each device, elimination of simple malfunctions);
ability to work with a computer, programs, databases;
an idea of diagnostic equipment that partially replaces a computer in its absence (control probes, multimeters, oscilloscopes, scanners);
knowledge of the specifics of different cars domestic and foreign production(comparative characteristics, selection of special equipment).

Also, you need experience. From the primitive soldering of contacts in the wiring to the feeling and understanding of the engine in all its subtleties. At every moment of work. Over time, intuition appears. It contains the philosophy of an intelligent person. His exposed nerve and salvation. All this is the basis of diagnosis. Without their assimilation, it is not worth getting down to business. You can't!

The essence of the subject

Translated from Greek, this word means to recognize, to be capable of deep vision.

Medicine interprets it as an analysis that reveals the essence of the disease.

Technical diagnostics does the same. Only not with a man, but with a machine.
By car in this case.

The principles of the approach to the procedure are the same for all equipment, whether it be a carburetor, an injector or a diesel engine.

What is included in the concept of "diagnosis":

Information about the state of the propulsion system (ICE) and the car as a whole.
Troubleshooting methods.

ICE state parameters:

engine power (l / s, W);
turns crankshaft(in a minute);
ignition (degree of advancing);
the position of the carburetor damper in accordance with the speed (for diesel engines and injectors, the state of the fuel pump);
detonation on each cylinder (synchronous with a spark on candles);
temperature (air inlet to fuel system, coolant in the cylinder block);
oil pressure (in the block and on the on-board controller sensor);
identification of errors in the electronic control unit (ECU) and their correction;
online exchange mode (receiving via the Internet additional information and capabilities from other diagnostic programs);
graphical display of parameters on a computer monitor;
voltage in the electronics network (V);
battery charge:
operability of the main electromechanical components: starter, generator, automatic transmission, interior heater fans and engine cooling radiator (for diesel engines and injectors - electric drives of fuel pumps);
ABS, ACC, Traction Control, 4WS systems, etc. etc.

Each of the parameters is constantly compared with the standard laid down by the car manufacturer. Any deviation is fixed and eliminated automatically using a specific diagnostic program. In problematic cases, mechanical intervention is possible. That is repair.

Troubleshooting methods. Two are mainly used:

Visual - what can be found "by eye":
— mechanical damage or deterioration of electrical wiring and pipelines of cooling systems, exhaust, hydraulic brakes and steering (for injection and diesel engines- fuel supply pipes from the pump to the spark plugs);
- oxidation of the contacts of the battery, starter, fuses, relays, etc .;
- “looseness” of individual functional units of the internal combustion engine and suspension (generator, starter mounts, as well as play in the steering rack and wheel struts);
- the condition of the air, fuel and oil filters.
Instrumental. Assumes the use of:
- the simplest devices (control probe, multimeter);
— electronic computers (motor-tester, scanner, computer).

Computer diagnostics

The most effective methods use sophisticated computer technology.

What does this method give? First of all, it allows you to control the entire internal combustion engine. Diagnostic accuracy is exceptional. Errors that may occur as a result are automatically eliminated using special programs.

Types of work:

stationary - with the device connected directly to the vehicle ECU (PC, scanner);
remote - via Bluetooth or Wi-Fi (tablet, smartphone).

Computer data processing is carried out by introducing "software" (programs) into the processor of the device, aimed at:

complex diagnostics (engine, outboard and steering system, brakes);

How to carry it out? Typically, drivers use the services of a car service. Is not the only option. With a certain preparation, it is possible to diagnose a car with your own hands.

Procedure description:

basic equipment set:
- computer;
- adapter "K-Line" with a cable on the Olb2 and Usb connectors (for a fixed connection) or an Elm327 adapter with bluetooth (remote research);
— diagnostic programs and drivers;
installation of the necessary "software" and "chip" (driver) on the computer platform;
"Firmware" (adaptation) of the ECU (provides communication between the controller and the computer and the transfer of all available car parameters to it.

Determining the status of the desired systems is done by gradually scanning each node. Defects that cannot be eliminated by the intervention of electronic correctors are eliminated during minor, medium or major repairs.

Conclusion

There is nothing impossible in the world. The term "computer diagnostics" scares away a lot of people. Mostly newbies. But this is at first. Everything in life happens sometime for the first time. This happens to cars all the time. And he is the life of a driver. His fate. Mastering the basics of understanding your technique is the best insurance against trouble. Go ahead. The road will be mastered by the walking one!

Andrey Goncharov, Expert of the Engine Repair section

Every motorist knows that the quality of the ride depends on the technical condition of the vehicle. By paying attention to the car and repairing it as needed, the owner reduces the risk of sudden breakdowns. Thus, timely prevention and troubleshooting can increase the reliability and safety of the car.

Unlike cars that existed decades ago, modern vehicles are much more complex. The abundance of functionality, including electronic, increases the risk of breakdown in a particular node. Many functions in a car are indispensable for driving, and their failure can cause problems for the driver and passengers.

In order to identify a problem in the car, it is necessary to use special equipment. Otherwise, the procedure will take a lot of time, and the driver will not be able to reliably identify all the breakdowns.

Almost every motorist gave his car for computer diagnostics. This service is performed by a professional who uses the appropriate technique. During computer diagnostics, all aspects of the technical condition of the car are checked. It allows you to identify existing and prevent possible breakdowns. Timely diagnostics informs the car owner about problems that he can fix, making driving safer.

Modern cars need quality and detailed diagnostics. That is why the computer procedure is important - without it, it makes no sense to start repairs. The times when you could inspect the car yourself in the garage are gone - today's cars have sophisticated equipment. With the help of computer diagnostics, you can check nodes, some of which did not even exist several decades ago. These include climate control, air suspension, Cruise control, anti-lock system And so on.

What is computer diagnostics and why is it needed

Computer diagnostics is a procedure necessary to quickly and accurately answer three questions about a car:

What technical condition is it in?
Are there ways to improve its performance;
What actions need to be taken to correct existing problems and achieve the desired state.

Computer diagnostics of a car reads error codes. During the procedure, a special scanner for car diagnostics, a computer adapted for this work, stands and readers are used. The wizard interprets the information it receives to determine what faults the diagnostic hardware is reporting. Based on the data received, the driver can make decisions to correct existing and prevent new problems. Thus, computer diagnostics has two purposes, both of which are important in the operation of the car.

Identification of breakdowns and the causes that led to them

The procedure for identifying problems in the car and establishing the reasons for which they occurred has always been a difficult and lengthy procedure. In addition, she did not have a guarantee - the diagnosis was not always successful the first time, and its accuracy left much to be desired. Use of computers in automotive diagnostics made the process much easier, more accurate and faster.

In fact, computer diagnostics is a test of each vehicle system. The list includes engine components, suspension, transmission, body electronics and other elements of the car.

After the procedure is completed, the screen of the diagnostic device shows all information about vehicle malfunctions and the reasons that led to them. The specialist deciphers the readings and sends them to the owner of the car. This allows you to assess the technical condition of the vehicle and eliminate problems that interfere with full-fledged reliable operation.

Identification of vehicle capabilities

Many machines - especially budget ones - have incorrect settings that were set at the factory. Thus, the software interferes with the realization of the vehicle's capabilities, and in some cases makes it difficult to operate. Most of these problems can be fixed. Computer diagnostics will be the first step in troubleshooting.

How does computer diagnostics work?

Detecting vehicle problems using electronic equipment occurs in two stages. First of all, the master performing computer diagnostics discusses the technical condition of the machine with its owner. The latter, in turn, expresses all complaints and wishes regarding.

The second stage is a series of procedures that the master performs. A test drive of the vehicle takes place, during which the master draws attention to the performance of one or another part of the car, which raises suspicions about a breakdown.

Next, the computer diagnostics of the car begins directly. First, the specialist fixes the problem. For this to electrical unit The machine is connected to a scanner that reads and analyzes information about the technical condition of the car. It checks all sensors, modules and systems of the machine, creating an overall picture. The data is displayed on the scanner display - usually in the form of graphs. The specialist deciphers the information that the scanner gives out, and then looks for best way repair or prevent damage. Modern scanners for computer diagnostics also allow you to make adjustments to the car settings, but such devices are expensive. The scanning procedure itself takes approximately 30 minutes.

Then there is the elimination or prevention of a malfunction in the vehicle system. Specialist selects best method for repairs, after which he contacts the owner of the car.

Advantages of computer diagnostics

Electronic analysis of the technical condition of the car is necessary for most cars for a number of reasons. In addition, computer diagnostics has several significant benefits before normal.

Fast and accurate fault detection

The procedure for computer scanning of car systems takes about half an hour. Diagnostics of a separate machine node is able to analyze its condition in a few minutes. As a result, the owner receives an accurate and detailed information about the problem. Data from more complex devices must be decrypted - an experienced master can handle this. Based on the information received, you can draw up a repair plan.

In addition, during computer diagnostics, it becomes possible to change the settings of various electronic systems of the car. Using the device, you can set the number of revolutions idle move, optimize the car for a particular configuration, replace software and much more.

Computer diagnostics will be especially useful when buying a used car. It will allow you to learn in detail about the condition of all components of the machine and identify breakdowns that the seller may be silent about.

Prevention of possible breakdowns

Diagnostics allows you to find out not only about existing breakdowns, but also about problems that may happen soon. So the car owner can save on major repairs by repairing one or another system in advance, and most importantly, reduce the risk emergency, which can take you by surprise on the road.

Selecting the type of diagnostics

In addition to general electronic analysis, the driver can choose diagnostics:

engine;
transmissions;
pendants;
Electronic equipment of the machine;
Auxiliary running systems(stabilization, anti-lock and others).

Thus, the car owner does not need to go through the full procedure. If it complains about a particular node, then a faster and more accessible analysis can be performed.

Procedure availability

Computer diagnostics, despite its wide capabilities and indispensable assistance in the operation of the machine, is accessible to any driver. The procedure has a reasonable cost and is carried out by masters in any city.

When is computer diagnostics needed?

Electronic analysis of the technical condition of the car is not mandatory procedure. However, in some situations, diagnostics are the best, and sometimes the only way to resolve machine issues.

The car shows signs of breakdown.

In the case when a code of one or another error appears on the dashboard of the car or the operational properties, it is recommended to undergo computer diagnostics of the node, the problem of which is reported by the system or suggested by the driver himself. Timely analysis of the technical condition of the car will prevent further development certain malfunctions, preventing their manifestation while driving. In addition, the elimination of breakdowns at an early stage will be cheaper.

Long trip planned

In order to prevent a possible breakdown from catching the driver by surprise, it is recommended to undergo preventive computer diagnostics before a long trip. During the analysis, the car owner can find out which elements it is desirable to replace before a long journey, as well as identify problems that have not yet made themselves felt and prevent their development. IN long trip, especially in an unfamiliar place, the search for a car service may take too much time or not be successful at all.

Active implementation electronic circuits into the device of the car gradually developed into the creation of a single system electronic control engine (ECM) under control. In parallel with this, not only, but also other components and assemblies of a modern car were equipped with electronic control modules. For example, the control electronics controls the brakes, airbags, transmission, individual chassis components, etc.

For control and monitoring in the device various systems there are numerous sensors that actively interact with the modules. Thanks to the presence of such modules, it is possible to quickly identify various faults and failures, that is, computer diagnostics of the car engine and other components are performed. Next, we will talk about what computer engine diagnostics gives, how you can check the operation of the motor and other units, and also where and how best to carry out this procedure.

Read in this article

Computer diagnostics of a car: what is it

To begin with, one of the most difficult tasks during the diagnosis of any motor is rightly considered precise definition breakdowns. On vehicles without an ECM, specialists have to focus on certain signs and symptoms of a particular malfunction, as well as perform whole line time-consuming diagnostic procedures, which are often accompanied by partial disassembly of the engine, removal of attachments, etc.

Now let's answer the question of what computer engine diagnostics shows. So, computer diagnostics of a car is a modern way to check those elements and assemblies that interact with the ECM. Moreover, malfunctions that occur in one node or mechanism can affect the operation of another, which is also often fixed during the test or allows you to more accurately localize the malfunction that has occurred.

Computer diagnostics allows specialists to evaluate important parameters during engine operation, and then compare the data obtained with those indicators that are considered normal. During engine diagnostics, the electronic control system itself, the ignition system, the cooling system, etc. are checked. At the same time, the quality of cylinder filling is assessed fuel-air mixture, composition of the mixture and a number of other parameters.

Such a check is carried out in stages, after which a summary error report is displayed. These errors are further deciphered, after which a decision is made to replace or repair certain components, parts and other structural elements. In other words, the introduction of electronic systems into the vehicle device allows you to dynamically control the operation and record errors in the ECU memory if they occur. Specified errors are stored in memory electronic modules in the form of codes. If the ECU fixes an error, a "check" may light up on the dashboard, indicating a malfunction.

It turns out that car diagnostics with a scanner or using a computer allows you to identify failures in operation of the internal combustion engine until a more serious malfunction occurs, as well as to accurately identify existing problems. This verification capability greatly simplifies the troubleshooting process and saves time. Computer diagnostics of the machine provides important information that displays general state parts, mechanisms, components and assemblies of the internal combustion engine, as well as the sensors themselves and control units of electronic systems. Otherwise, it is possible to comprehensively assess the technical condition of the engine and other vehicle components.

Computer diagnostics of the engine: do-it-yourself, on-site service or check at the service station

It is quite obvious that computer diagnostics will require special equipment. On vehicles with an ECM, there is a so-called diagnostic connector, into which a scanner, computer or laptop is connected. Please note that some cars may also require special adapters. You also need to have installed software that allows you to interact with the electronic systems of the car, as well as certain skills and knowledge to work with programs and equipment.

In order to understand where to do computer diagnostics of the engine and how to perform this task correctly, you can use one of the available methods:

contact specialized centers that have all necessary equipment to carry out inspections;
order a service called on-site computer diagnostics of the engine;
check your car yourself;

In the first case, you only need to deliver the car to the territory service center and pay for the service. The pluses include the fact that at many large stations masters work with great experience, and it is usually possible to repair the damage and make necessary repairs right on the spot. The disadvantages include the cost of computer diagnostics of the engine, which can be in full about 15-20 USD. and more.

On-site diagnostics of the car may be needed if it is problematic to deliver the car to the service station for any reason or a used car is selected. It should be borne in mind that this service can be provided both qualitatively and professionally, and provided by people with little experience.

If on-site car diagnostics are offered by large service stations How additional service then there shouldn't be any problems. Specialists themselves will come to the place where the car is located, connect a scanner or a laptop with the right programs, thanks to which the machine will be in-depth checked, decoded and / or reset engine errors, etc. The extra charge for departure is naturally added to the basic cost of diagnostics. As for small entrepreneurs, in this case, the specified diagnostics can be both complete and carried out taking into account the minimum set of equipment and knowledge. It is this development of events that should be feared. In other words, you need to pay for the departure and the service, while the diagnosis can be superficial and no different from the one that the car owner is able to do with his own hands, taking into account the minimum financial costs.

We are talking about connecting a smartphone or tablet based on Android / IOS or Windows through an adapter to the diagnostic socket. The difference will be only in the price of the service, which for one trip can be equated to market value specified adapter. For this reason, it is more profitable to purchase an OBD2 diagnostic scanner adapter, install the necessary software on a smartphone / tablet and check the car yourself. By cons this method It should be attributed to the fact that more programs for interacting with adapters have a rather limited functionality. The advantage is that you can check the car anywhere and anytime, and it is also convenient to identify a malfunction that is not always present, but occurs with some frequency.

What is the result

In view of the foregoing, it becomes clear that a modern car has many subsystems that are interconnected and form a single electronic system. This system not only manages, but also controls the correct operation of components, mechanisms and assemblies, taking into account a large number of parameters.

For this reason, computer diagnostics of a car is a kind of diagnostic and preventive measure, which allows you to assess the condition of the car, timely notice the failure or breakdown of certain elements. As a result regular check able to protect the engine and other units from further serious damage, which tend to progress, remaining unnoticed at the initial stage. In other words, it is important to reveal hidden and minor defects to the point where they lead to more expensive and complex repairs.

It is optimal to pass the indicated diagnostics at each maintenance, as well as in the event of any deviations in the operation of the engine or other systems (for example, steering, brake system), sunbathing emergency light bulbs on the dashboard, etc. Also, computer diagnostics must be carried out if you plan to buy a used car, an expensive repair is planned based on any indirect signs that are not finally confirmed by error scanning.

What is OBD?

Let's start from the very beginning. To connect diagnostic equipment to the car, you need a special connector that all cars now have, and which is sometimes called simply OBD-II. In fact, OBD-II is not a connector, but a whole system. on-board diagnostics. And despite the fact that it firmly entered our lives only 20 years ago, its history begins back in the 50s of the last century.

In the middle of the twentieth century, the American government suddenly came to the conclusion that the rapidly growing number of cars somehow had a bad effect on the environment. The government began to pretend that it wants to improve this situation at the legislative level. Automakers, in turn, began to pretend that they are complying with invented laws.

Extremely diverse diagnostic systems appeared, the task of which was limited to monitoring emissions into the atmosphere (and since there was no sophisticated equipment, the maximum that could be more or less adequately monitored was fuel consumption). No one (sometimes even the manufacturers themselves) could use such systems normally. And when, by the mid-70s, the Air Resources Board (ARB) and the protection agency environment(Environment Protection Agency, EPA) began to realize that nothing good could be achieved, they began to strongly recommend the introduction of new systems.

They would not just blink a light, “if something went wrong,” but would allow you to quickly check the car for performance. environmental standards. The first manufacturer to respond was General Motors, who developed his ALDL interface. Of course, we have not yet talked about any world standard, and about the American one too. In 1986, ALDL was modernized, but things never reached the desired scale. And only in 1991, the California Air Resources Board (California Department of Air Control) obliged all American automakers to equip their cars with diagnostic OBD-I system(On-Board Diagnostic), developed in 1989.

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Degradation of service: why do service stations diagnose cars using the “poke” method?

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What could be monitored using OBD-I? By itself, priority was to monitor the composition of the exhaust gases. You could follow the work electronic system ignition, oxygen sensors and systems EGR recirculation. In the event of a malfunction, the MIL (malfunction indicator lamp) lighted up. No more accurate information could be obtained, although over time the light bulb was taught to blink with a certain sequence, which made it possible to identify at least a faulty system. But this soon became not enough.

In January 1996, the presence new version OBD-II became mandatory for all cars sold in America. The main difference of this diagnostic system From OBD-I, it became possible to control the power system, and it could also be checked on the car using a plug-in scanner. This was what the police did. They didn't give a damn about anything but toxicity - after all, this whole system was originally developed to control exhaust gases. It was assumed that the diagnostic system on the new car had to work for five years or one hundred thousand kilometers. But this is not the end of the OBD-II story.

In 2001, all cars sold in Europe had to have an EOBD (European Union On-Board Diagnostic) system, now with a CAN bus (which will be discussed in more detail some other time). In 2003, the Japanese introduced a mandatory JOBD (Japan On-Board Diagnostic), and in 2004, EOBD became mandatory for all diesel vehicles in Europe.

This is very (even too) Short story OBDII. I deliberately did not complicate it, you are hardly interested in reading about the recessive and dominant bits of the Controller Area Network specification? So I think that's enough to get started. Let's take a better look at OBDII connector"live".

Meeting place can not be Changed

I have already said that through diagnostic connector Californian cops, if desired, should have easily connected to the system itself. To simplify the task, it was decided to install the connector no further than 60 cm from the steering wheel (although, say, the Chinese often ignore this requirement, and sometimes Renault engineers indulge in the same). And if earlier the connector could be found even under the hood, now it is always within the reach of the driver. What is a connector?

In general, it is called DLC - Diagnostic Link Connector. It is quite obvious that the block itself also began to meet the same standard. The connector has 16 pins, eight in two rows. The standard also defines the purpose of the pins in the block. For example, pin number 16 (the rightmost in the bottom row) should be connected to the "plus" of the battery, and the fourth should be ground. And yet, six contacts are at the disposal of the manufacturer - something can be located there at his request.

Often you can hear the word “protocol” from diagnosticians. In this case, this is the standard for data transfer between individual blocks of the diagnostic system. Here we are already dangerously approaching computer science, but nothing can be done: computer diagnostics. You'll have to endure a little more.

OBD-II developers provide five different protocols. To put it very, very simplified, it's five various ways data transmission. For example, the SAE J 1850 protocol is used mainly by Americans, the data transfer rate for it is 41.6 Kb / s. But ISO 9141-2 is not common in the USA, the transfer rate here is 10.4 Kb / s. However, we do not need to know all this.

For now, just remember:

diagnostic block OBD-II is the same everywhere, the pinout is the same, and which connectors will be used to connect the scanner depends on the protocol used by the manufacturer.

Well, now let's try to diagnose the car - specialists from the Speed Laboratory company will help us with this. Along the way, let's see what a real diagnosis is.

What can diagnostics do?

Let's start with the fact that connecting a cheap multi-brand scanner and counting one or two errors is not even close to diagnostics. And it would be a big mistake to believe that the diagnosis is made by the scanner, and not by the person. In fact, they work in pairs, and if one of them is significantly dumber than the other, nothing good comes of it. I hate numbered lists, but I use one to more clearly show what should be included correct computer diagnostics:

Collection of anamnesis.
Reading existing and stored errors.
Viewing the data stream (Live Data).
Data logging "in motion".
Interrogation and comparison.
Actuator tests.
The use of instrumental diagnostic methods.

Too many unknowns? We will calmly reach each of the points.

There are also post-diagnostic works: adaptation, activation additional features… But about it in one of the following publications. For now, let's focus on troubleshooting and go through all the steps.

Collection of anamnesis

Before starting work, a good diagnostician will definitely ask the owner what is wrong with the car, how the malfunction manifests itself, under what conditions, with what frequency, what preceded the malfunction ... In a word, he will behave like an experienced doctor, and not from a free clinic, but from a good medical center.

Our experimental MINI is absolutely healthy, so there is nothing to ask in this case. However, sometimes it makes sense to carry out diagnostics as preventive measure without waiting for check engine will start to shine constantly or wink periodically from the instrument panel.

Reading existing and stored errors

So, we connect a scanner and a laptop with software from BMW (we won’t remind you how BMW and MINI are connected, everyone is literate here). Of course, through the diagnostic connector. By the way, Mini does not want to normally pass diagnostics on one battery, so we connect external source nutrition. But this is a feature of the car, the exception, not the rule. Now we are waiting for the establishment of communication with the car. We look at the picture on the laptop screen.

First of all, we can see general information about the car - from the current mileage to the engine number and gearbox. By the way, if you buy a used car, then often diagnostics will help determine its true mileage, which will also be visible, for example, in automatic transmission.

Or even more interesting: if you open the repair history, you will see at what mileage the last intervention was carried out (maybe someone threw off errors, adapted some mechanism, or did something else). And if there is a mileage of 100 thousand, and only 70 on the odometer, then someone wants to deceive you. It is far from always that such an opportunity is 100%, and the “rollers” of runs are often inventive and not lazy - sometimes they clean up runs everywhere, although this is rare.

But we digress. We quickly scan for errors and in the "Error Accumulator" section we still find such entries that indicate errors in the electric power steering!

I emphasize once again: if the “check” is not lit on the machine and any obvious faults doesn't mean they don't exist. The electronics may not work correctly without notifying you without connecting the scanner.

Therefore, computer diagnostics, especially if you have expensive car co complex electronics, must be carried out regularly so that many breakdowns are preventively eliminated until they result in something serious.

But back to our MINI. We open the EUR error record and look at the so-called Freeze Frame (frozen frame) - it describes under what conditions this error appeared. In our case, this happened once with a run of 120 thousand kilometers, at a speed of 117.5 km / h, the battery voltage was 16.86 V.

The data in the Freeze Frame helps to understand why the error occurred. Not always, of course, but any related information about speed, mileage, voltage, etc. may be important. This is all provided that the specialist knows how to think.

It happens, after all, that home-grown "diagnostics" simply see which part in the car is "buggy", and immediately offer to change it in the assembly, because, they say, only the Holy Spirit knows the cause of the error, it is impossible to unravel it. This is all from great greed and lack of professionalism. And we're moving on...

Viewing Live Data

Live Data is the data that can be obtained in real time. There are simple data - for example, engine speed or coolant temperature.

And there are those that are generally impossible to find out without a scanner. For example, the voltage of the pedal position sensors (we are talking about the electronic gas pedal). There are two of them, we look at the readings: 2.91 V on one and 1.37 V on the second. Now we press the pedal and look at the values: 3.59 V and 1.58 V. Actually, this is Live Data - what happens to the mechanism in real time.

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The data stream can also be viewed on the go. It can be very useful to see how the on-board electronics of the car react to various manipulations, and what Live Data shows at the same time.

Polling and matching

This is the work of the diagnostician, not the equipment. After the machine is tested by all accessible ways, the readings taken are to be comprehended and compared. Was the voltage normal? What about resistance? What about the temperature? Well, and so on.

Actuator test

It is carried out to check their performance. Usually - just to make sure that the node works as expected. We go to the menu section "Activation of the part" (yes, the Russification here is somewhat strange) and start, for example, the electric fan of the cooling system. Works. What can it be useful for? Let's say the engine is overheating. If the fan had not turned on forcibly, the cause of overheating would have been revealed.

Using Additional Measuring Instruments

It happens that diagnostics cannot show which of the elements of the system has failed. Take, for example, the same electronic pedal gas." Let's say the voltage is abnormal. The scanner will show this, we have already seen this. But what is the reason for the voltage drop?

Here, only measuring the resistance of the rheostat with an ohmmeter and visually inspecting the tracks for damage or worn contacts will help. Or another example. Diagnostics shows errors on the crankshaft and camshaft position sensors. Most likely, this indicates a shift in the timing phases, that is, a chain stretch. How phase shifted? Only an oscilloscope can help with this. Still, replacing the timing chain is an extremely expensive job, especially on some kind of V 8. It’s better to know for sure here.

One oscilloscope is also sometimes not enough. For example, this can also include pressure testing of the intake with a smoke machine, and a test of the performance of injectors "with a return", and control of the same diesel injectors on a special injector stand, and much more…

Articles / Practice

More powerful than according to the passport: we test Š koda Octavia RS on the stand

More, more! Before turning off the ESP and putting the arrow in the red zone of the tachometer, let's at least study our patient a little - the Octavia engine. Believe me, there are many amazing things here. The two-liter engine of the EA888 family ...

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You can still apply, although few people use it due to the lack of equipment. After all, measuring on the stand allows you not only to see the numbers of power and torque, but also to look at the nature of the curve of both and simultaneously take data on boost pressure, AFR, exhaust gas temperature, torque distribution along the axles and wheels, and much more. But this is exotic in Russia.

Therefore, we note this item separately: a real diagnostician does not disdain to get his clothes dirty, because at the stage of instrumental diagnostics, you will have to open the hood, get into the wiring, dismantle problem sensors or components and check their condition visually and for correct functioning, ring the wiring, connect an oscilloscope, multimeter and other necessary appliances. Computer diagnostics involves the use of not only one scanner (and in real life there should be more scanners - more on this in a separate article), but also other diagnostic tools.

Logging

It is used in a case that would definitely baffle me: if the error has a floating character. Just the situation when the service usually says: “well, now everything is working, but as soon as it happens again, come.” Indeed, such a malfunction can be difficult to determine. But there is a way out.

A special scanner is connected to the diagnostic connector (usually a mini-scanner that is simply inserted into the OBDII connector and does not hang, does not dangle, works autonomously, does not interfere with the driver. In general, it does not require any participation of an ordinary user - a car service client) and the client is sent ride according to your needs.

The scanner, meanwhile, is working hard, writing a log, and at the time of the manifestation of the problem, it additionally registers the error itself and the conditions for its manifestation. The method is convenient, and most importantly, practically indispensable in the presence of complex "floating" errors. And another advantage is that the specialist does not have to sit in real time and monitor everything that is happening in the car. Sometimes it is simply impossible, and if possible, it is very difficult. It is much more convenient then just to pick up all the records and sit thoughtfully over the logs.

And in the end I will tell…

All of the above is just the tip of the iceberg. We will gradually raise the entire block, but not immediately.

For example, we did not say anything about codes, although this topic is very interesting. Many have probably heard something like this: “I have a code P0123. What does it mean?". Yes, you can see. This is the position sensor output high. throttle valve"A". In short, all errors are divided into groups. P - engine and transmission, B - body, C - chassis.

There are divisions inside too. It’s not necessary to list everything for a long time, but at least for example: P01XX - mixture control system, P03XX - ignition system and misfire control system, but from P07XX to P09XX - transmission. Subsystems are indicated instead of XX. For example, P0112 - low level intake air temperature sensor, and P0749 is an error solenoid valve pressure adjustment. There are hundreds of codes, but an ignorant person will not get anything sensible from this information.

In general, of course, the question is important: suppose you have made a diagnosis somewhere, but what to do next? In this case, you can once again check the qualifications of specialists. It is almost always possible to understand the origins of the appearance of a particular error. So if you hear advice to change parts one by one until the car runs fine, get your feet out of such a service. You can understand them: changing parts sold at a premium is much easier than studying to be a diagnostician and poking around in little things that will not bring a lot of money.