Computer diagnostics of a car - how and why is it carried out?

Car diagnostics - what is it and what is it used for?

It is no secret that all new and modern cars are literally stuffed with various types of electronics that directly monitor and control the technical processes of the car and help to move safely on this vehicle. All this technological progress, which does not stand still, leads to the fact that all these systems need to be comprehensively checked and tested in case of failure or incorrect operation of other electronic devices using professional scanners and computers, thereby conducting computer diagnostics . This article will focus on diagnosing a car using a computer, but many still ask questions, let’s take a closer look at how to carry out diagnostics and why they are carried out.

Let's get started, what is computer diagnostics? - this is not a tricky process in connection with which data is read from the electronic unit of a particular system, such as error codes that arose during operation, which, during decoding, reveal a malfunction of a particular unit or sensor. After repair and elimination of the breakdown, error codes are cleared from the memory of the vehicle unit. All these procedures can be performed by professional diagnostic scanners and simple PC-based diagnostic adapters. Current scanning systems, in conjunction with their software, are already able to read all the parameters of all sensors in real time, and therefore monitor all technical processes occurring in the car, be it the rotation of the crankshaft or the quality of the prepared air-fuel mixture in the engine, they also display the work and other systems, gearbox, ABS and other systems.

During professional computer diagnostics, electronic engine control units are often reconfigured, thereby performing optimization, for example, for the desired vehicle configuration. The adjustment may concern adjusting the idle speed, down or up, or adjusting the parameters of the lambda probe, thereby changing the composition of the prepared mixture. And using additional modules and plug-ins, it is possible to reprogram the car’s electronics, update the interface and maps of navigation systems.

How is computer diagnostics of a car carried out?

• They connect a diagnostic scanner with advanced software to the vehicle systems through the OBD2 diagnostic connector, the diagnostic scanner reads and displays fault codes using its software.
• Having received fault codes, the diagnostic scanner can decipher the received ones, displaying them in a readable form, based on the data received, experts make a verdict about the malfunction and incorrect operation of one or another component of the car.

Are there any special features for trucks?

Computer diagnostics of trucks is no more complicated than that of cars, but it is usually more extensive. Although there are no fundamental differences. The procedure includes studying:

• electronic units;
• fuel system;
• transmissions;
• operation of the engine and actuators;
• pneumatic system;
• condition of auto electrics.

Some identified errors are corrected immediately after detection. Others require the truck to be repaired.

When should computer diagnostics be performed?

Usually, in the event of any malfunction, a “check” warning light lights up on the instrument panel, indicating errors in the system, but it is worth noting that when the car begins to work unstably and malfunctions are observed visually in certain components, but there are no error messages, then everything costs exactly diagnose the car. Diagnostics can also reveal adjustments in the mileage of a given vehicle, so before purchasing a used car it is worth conducting comprehensive computer diagnostics . Experts recommend carrying out auto diagnostics of all systems at least once a year, thereby identifying the malfunction in advance and eliminating it before expensive repairs are needed, a kind of preventative measure for car disease and identification and treatment in the early stages.

Computer engine diagnostics

It should be performed in cases where engine warming up has become very long, has begun to consume too much fuel, unstable operation of the internal combustion engine or poor starting, power characteristics have noticeably decreased, extraneous noise in the engine, black or white smoke from the exhaust pipe is observed during operation, unstable idle rpm During the diagnostic check, the following systems are tested:

1. Power supply must be in accordance with the standard
2. Fuel injection system monitoring
3. The pressure of the combustion chamber is measured - compression and others.

Computer diagnostics of automatic transmission

It should be performed only in cases where a particular gear is not engaged, extraneous noise is heard, jerks are observed when switching, an oil leak is observed, fuel consumption has increased, or slipping when switching. Based on the automatic transmission fault codes and the temperature of the working fluid sensors, a verdict is made on the further operation of the automatic transmission.

Computer diagnostics of electronic and electrical systems of a car

This implies in-depth testing of all electronic components:

1. Cruise control systems help you move at a given speed without driver intervention.
2. Air conditioning and climate control systems
3. Navigation systems
4. Parking systems - parking radars, etc.

Comparing computer diagnostics of a car and simple traditional diagnostics, so to speak, the computer one identifies faults much faster and at a lower cost for subsequent elimination, while the traditional one begins to satisfy.
Today's cars contain microchips with the help of which all control over the operation of the car is performed, and these microchips can be controlled using a computer and appropriate software. Much depends on a qualified approach to diagnosing a car, that is, an ordinary person who does not have the appropriate knowledge is not able to correctly evaluate all the readings and process the data, so it is better to entrust this to professionals. Continue

What to check at a service station

When the car is taken to a service center, the best solution would be to ask the technicians to carry out a comprehensive diagnosis. The cost of the service varies from a thousand to several thousand rubles depending on the make and model of the car.

The full diagnostic procedure usually includes:

• Check on a lift;
• Engine diagnostics;
• Suspension inspection;
• Assessing the condition of the steering;
• Checking the paintwork;
• Diagnostics via computer.

This list is not complete, but thanks to these basic procedures, the client will find out whether the car has been in an accident, and whether it has internal technical problems not related to the accident.

Service station technicians, using special equipment, will find out whether the car has a real mileage, the condition of its engine, suspension elements and much more. Based on the results of the inspection, a list of necessary work will be compiled to bring the car into ideal technical condition. If you purchase, you will know how much money to budget for subsequent work.

Other methods for examining the performance of the power unit

Self-diagnosis of engine malfunctions allows you to determine their cause. By promptly identifying the problem area of ​​the car with your own hands, you can solve two problems at once. Firstly, to avoid the material costs of performing a similar service by mechanics in specialized workshops. And, secondly, get rid of the need to carry out unplanned major repairs, which also lead to significant financial losses.

Despite the growing popularity of the Internet and the availability of computer diagnostics of a car engine, the equipment’s high cost can scare away the average person who does not have a significant bank account or other material means. Such car enthusiasts resort to traditional methods of determining problems in power units, based on mechanical research:

• visual diagnostics of gasoline engines is not much different from a similar process for diesel units. The main requirement that affects the quality of the final result is a thorough knowledge of the motor design, the location and appearance of all parts and mechanisms provided by the manufacturer. A fairly experienced driver is able to approximately determine which element of the power plant is causing the malfunction. Having disassembled and carefully examined the problem unit, they discover a faulty fragment;
• Acoustic inspection consists of identifying a breakdown by extraneous sounds emitted by a functioning engine. Noises uncharacteristic of a working unit indicate malfunctions in the gas distribution mechanism or failed parts of the cylinder-piston group.

Unfortunately, it is not always possible to immediately detect the cause of a malfunction. For particularly serious cases, comprehensive engine diagnostics are provided, which can reveal even a hidden internal defect. It consists of a thorough examination of all systems and mechanisms of the car engine with your own hands.

However, if the cause of the breakdown is in the electronic system and is detected by computer scanning at the first stage of the study, further research is not necessary. The diagnostics of gasoline engines can be considered complete at this point, since the result has been achieved.

In what cases is diagnostics not needed?

There are few situations when a used car does not need to be checked by a service center. If the car is being sold by a relative, good friend, or the vehicle is being sold by an official dealer, in these cases the car does not need to be checked. In all other situations, do not neglect a trip to the service center or ordering on-site diagnostics.

An on-site inspection is an alternative to a trip to a service station. Technicians with equipment will come to the car and conduct an inspection where it is convenient for the client. The cost of an on-site examination starts from 2,600 rubles; its result will be a complete understanding of the technical condition of the vehicle.

Before proceeding to inspection and diagnostics of equipment, check the vehicle history using the Autocode service. Information on more than 12 databases will be collected in a few minutes. For 349 rubles you can find out everything about the car (mileage, deposits, restrictions and much more), and decide in advance whether to look at the car or refuse to buy.

What is diagnostic equipment used for?

Using diagnostic devices, the technologist receives detailed information about the vehicle itself and its systems. He can find out the software version of devices that control the operation of the engine and other electrical devices of the car. Testers show the vehicle's VIN, engine type and classes of various control systems.

In addition, diagnostic devices analyze the state of the operating system and provide information about this in the form of tables and graphs. Using the tester, you can find out the exact temperature of technical fluids, the speed of rotation of the crankshaft, the effective value of the voltage in the electrical network, the weight of the air masses inside the engine, the position of the fuel valve, and the composition of the flammable liquid entering the cylinders. The tester collects data from all system sensors.

The collected data can tell an experienced diagnostician a lot. By comparing and analyzing the information received, the specialist identifies those faults that are not available for standard self-diagnosis functions.

For example, the fuel supply system is being checked. The tester shows that the throttle is halfway down, but the gas pedal is not pressed. What could this mean? The detected discrepancy indicates a malfunction of the damper position sensors or mechanical damage.

Another important function of diagnostic instruments is reading data from the controller’s memory. The electronic control unit has the function of independently collecting and storing data on the operation of various vehicle systems. It also records the location and nature of any faults that occur. Diagnostic tools read this information and display it in the form of codes.

A uniform error coding standard is used throughout the world.

For example, the P0125 code indicates that the engine coolant temperature is insufficient. “P” is a letter indicating the location of the fault (engine). The symbol “0” indicates that the error is included in the table of established standards. Non-standard defects are indicated by the numbers “1” or “3”. “12” - determines the location of the malfunction of additional components (oxygen sensor). The last number indicates that the oxygen sensor is not doing its job.

Another important concept that you need to know when working with diagnostic equipment is the status flag. This word indicates additional information about the detected malfunction. The status flag shows the current state of the error. It informs about the degree of activity of the defect and its effect on increasing toxicity. Different controllers have different sets of status flags. They can additionally inform about the number of times a malfunction occurred and the time that has passed since the controller was rebooted.

Freeze Frame mode. This is a mode for fixing system parameters at the moment when the fault was active. The tester provides this information in the form of a list that helps identify additional error conditions. We find out the speed of the car, the crankshaft speed, and the ambient temperature at the moment when the defect appeared. This helps to quickly find the cause of the malfunction.

Diagnostic equipment is also used by specialists to check the executive components and devices of the system. When diagnosing, it is often necessary to check the activity of the system’s executive units. The tester does this using commands to turn devices on and off.

For example, the condition of the injectors is checked only in operating mode (when there is pressure in the fuel system). To do this, you need to periodically turn the fuel pump on and off. The tester does this automatically by monitoring the fuel pump relay.

Diagnostic tools can easily “study” any relay or sensor in the system, injectors, ignition unit, and even the canister purge valve.

A modern car cannot do without special diagnostic procedures. Autodiagnostics allows you to find almost any fault in a short time. In this case, there is no mechanical intervention in the working components and systems of the machine, which greatly facilitates the work.

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Self-check of a car engine with an injection system

In most modern power units, fuel enters the fuel system through special elements that spray it, called injectors. This feed is considered more progressive than in carburetor cars. However, errors in work sometimes arise in it. Since its further combustion depends on the quality of fuel atomization, it is extremely important to prevent failures in the mechanisms that supply fuel.

Personal diagnostics of injection engines is carried out to identify faults in the injection system. Timely elimination of problems discovered during the study can prevent more significant troubles that threaten unplanned financial losses caused by the need for major repairs.

Ideally, a set of works to determine the performance of injection engines consists of several stages:

1. computer examination;
2. checking the functionality of the injection system;
3. visual examination of the mechanical elements of the power plant.

For an injection engine, self-diagnosis is carried out using special equipment. Its detailed list requires separate consideration.

Diagnostic equipment for checking an injection engine

Inspecting the condition of a car's injection system with your own hands is quite accessible to almost every driver. However, it is necessary to first prepare the following devices and accessories:

1. Fuel pressure indicators are controlled by a pressure gauge. This allows you to promptly identify problems in the operation of fuel equipment;
2. The diagnostic cable connects the power unit to the computer. Smart electronics can determine the cause of errors in operation. In some modern car models, the manufacturer provides engine self-diagnosis. In such cases, faults are detected by the on-board computer;
3. the state of the compression level indicators in the cylinders is monitored by a special device called a compression meter;
4. An LED probe is used to determine the polarity on the injectors and the ignition module. Checking the integrity and functionality of electrical systems is carried out with a multimeter.

It should be noted that in most cases, self-diagnosis of an injection power unit is limited to computer scanning of its electronic components. However, a full range of measures to identify faults requires a thorough approach.

The main stages of checking the performance of the injector

The need to inspect an injection engine arises when errors appear in the stable operation of the engine or in cases where the car refuses to start for no apparent reason. Self-diagnosis involves sequentially performing the following manipulations:

• First, the functionality of all sensors is checked. To do this, do-it-yourself computer scanning of the car’s electronic systems is used;
• then the performance of the ignition system is assessed. The test is carried out using an LED probe;
• At the next stage, the quality and reliability of contact connections is assessed. A fairly experienced driver who knows his car thoroughly is able to identify deviations after a visual inspection. A more detailed study is carried out using a special device called a micrometer;
• Next, the functionality of the candles is checked;
• The performance of a gasoline pump is determined by its performance. To assess the performance of the fuel pump, the fuel pressure in the system is measured;
• disturbances and malfunctions in the operation of the injection engine are indicated by changes in the level of compression in the cylinders. This indicator is measured using a compression meter.

Main stages of verification

Computer diagnostics is carried out as follows:

— existing errors are read

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Using special testing tools, specialists diagnose digital media data and fault codes. Obtaining them makes it possible to give a detailed description of the breakdown. In this case, it is very important to be able to work with a scanner, since the master must know how to “decipher” the received data. - analog test
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It essentially complements the first stage. Specialists carry out diagnostics of electrical circuits of vehicles (battery, generator, cords, contacts, etc.). All this is checked to ensure that the electrical equipment is in good working order. If the electrics turn out to be faulty, then obtaining any digital information will be meaningless. — analysis of the information received and the result
. It must be said that modern equipment for vehicle diagnostics is very accurate. It can even determine if a tire storage service has not been ordered previously. All information is based on the condition of the tire. After all the data is received, the final result is summarized. Deciphering the codes allows you to very quickly find any malfunction or, on the contrary, make sure that everything is in order with the electrical equipment. A simple car enthusiast is not able to do all of the above himself, since this requires special knowledge and skills in handling equipment. After diagnosing and correcting all faults, specialists can only reconnect to the computer and delete the codes that were previously recorded. After restarting the system, it will continue to operate, and old errors will not be taken into account. Experience indicates that this service greatly facilitates troubleshooting. For a motorist, such a service has at least two positive aspects. He can have complete confidence that his machine is working properly. But even if there are breakdowns, they will be fixed very quickly.

19.09.2017