Considering that the "vital activity" of a vehicle directly depends on the correct operation of all its constituent systems, there is nothing surprising in the existence of a certain "think tank" that monitors their state and activity. This center is the electronic control unit (ECU). Malfunctions of this structural part of the car are immediately displayed on the operation of the power supply of the transmission, exhaust system and other "controlled" elements. Now we will try to understand the principle of operation of the electronic control unit, and also consider the main causes of its breakdowns and ways to eliminate them.

1. The principle of operation and features of the electronic control unit

In the field of automotive electronics, this device is a general term that unites any embedded systems, which, in turn, control one or more mechanisms in the subsystems of the car. The types of electronic control units are divided into: electronic engine control unit (most common type), central control unit, combined engine transmission control unit, brake control unit, central control module, main electronic module, suspension control module, body controller, central synchronization module, etc.

Sometimes, all these systems, taken together, are called a car computer, although from a technical point of view, these are several blocks. Quite often, one assembly can include a large number of separate control modules. Thus, individual modern cars combine up to 80 electronic control units, and their embedded software continues its successful development. In this regard, the management of an increased number of complex vehicle ECUs plays a major role in its efficient operation today.

The main type of electronic control units for a car is the engine ECU(it is also often referred to simply as an electronic unit). The use of this device qualitatively optimizes a number of basic vehicle parameters: power, fuel consumption, level of harmful substances in exhaust gases, etc. It is presented in the form of a kind of computing device, the main task of which is to process the information coming from the input sensors, and transmit the corresponding control commands based on it to various engine systems.

From the constructive point of view, such a block consists of a box (hardware) and the software necessary for the operation, the central part of which is the processor. It is here that the data from all the sensors of the power unit comes in, after which they can be processed and further analyzed. In addition to traditional sensor information (such as position and RPM or air flow), additional data have been added about vehicle speed, oxygen level in the exhaust gases, road irregularities, a request to turn on the air conditioner and a bunch of other signals aimed at optimizing the engine's workflow. The number of sensors of modern cars has long exceeded 20.

Installation of software is required to carry out computational operations. A distinctive feature of modern electronic control units is the possibility of reprogramming, which made it possible to move away from the serious restrictions set by the factory program and open up new horizons for the use of engine tuning, for example, installing a turbocharger or equipment for using alternative fuels.

We will not now go into the essence of the activities of each individual ECU, since this will take a very long time, but rather we will focus our attention on the described electronic engine control unit, because, as we have already noted, it is he who is the key to the effective functioning of the power unit, and therefore the whole car.

2. Reasons for ECU failure

Any electronic control unit is an important piece of equipment, and the appearance of malfunctions in it can cause the entire mechanism to malfunction. As a kind of "think tank" of the entire ECU system, it is responsible for all processes occurring in it, so even minor damage to the microprocessor can cause malfunctions in the transmission, emission control system, charging system and many other components of the vehicle's viability. The main signs of failure of the electronic control unit are considered to be refusal to start the engine, constant messages about violations of its operation, which are not cleared in any way, and some other symptoms.

In principle, the appearance of malfunctions in the operation of an ECU is a rather rare phenomenon that, usually, cannot be predicted, and in order to identify and confirm a breakdown, manufacturers and repair companies have to perform the following checks:

- checking the electronics and the possibility of overheating;

Checking parts for corrosion and destruction;

Assessment of the assembly quality of the block itself, conduct fractography.

Fulfillment of all the above conditions at the test stage will prevent damage in the future and significantly increase productivity.

Today, there are a lot of reasons for the failure of this device, and they all depend on the type of electronic unit, its location and key functions. Among the most common of them, they distinguish the lack of contact with the ignition unit, various sensors, an operation controller, a temperature sensor, as well as the impossibility of monitoring the operation of the ABS sensor. In addition, mechanical damage from vibration and shock, or ingress of moisture on the microcircuit, seriously affects the breakdown of the device (water seeping inside, often causes short circuit and corrosion).

Thus, in the event of any malfunction, an overvoltage may occur in the electronic unit, which often completely disables the system. Also, specialists of many car services, the environment of possible causes of ECU breakdown, highlight a significant proportion of those that were formed as a result of attempts by motorists to repair the device on their own, or entrusted this matter to dubious professionals.

Special attention, I would like to pay attention to the causes of breakdowns that occur in the electronic engine control unit. These include:

- "lighting" from a car with a running engine;

Inconsistency of polarity when connecting the battery;

Lack of the necessary knowledge and skills when installing alarms and carrying out electrical repairs;

Removing the battery terminal while the engine is running;

Inclusion of the starter with a disconnected power bus;

Ingress of moisture into the electronic control unit;

Short circuit or complete break in the wiring;

Contact with the electrode from welding on the wiring or sensors of the vehicle;

Malfunctions in the high-voltage part of the ignition system: coils, wires, distributor, etc.

However, no matter what type of control unit we are talking about, the main thing to remember is that it consists of many rather complex connections, which means that attempts to independently carry out repair work can provoke serious problems in the operation of this unit. As for representatives of new models of vehicles, when faults appear in the control unit, it is recommended to completely replace the specified device. If the car is still under warranty service, then it would be reasonable to contact the dealership, where the unit will be replaced.

Note! Repair of electronic engine control units of some car models is generally impossible, even if you seek help from the most qualified professionals. However, be that as it may, the initial stage of solving the problem, first of all, is high-quality diagnostics, and then, after consulting with specialists, you can decide the further fate of the failed computer.

3. Repair of the electronic control unit

Repairing an electronic control unit is a rather complicated and time-consuming procedure, which is recommended to be used in extremely rare cases: when a replacement is not possible for some reason, or when it is too expensive for the car owner. Experts do not advise at all to start independent repair actions, since there is a high probability of damage to the electronic "brains", which, in turn, will disable all accompanying vehicle systems.

Given the complexity of the ECU device, it cannot be repaired in a conventional service station, where, after making sure that there is a problem, it will simply be replaced with a new one. For a more significant check of the unit's operability, it is necessary to conduct special testing using special equipment, which is available only in specialized service centers. Before replacing a failed mechanism, you should find out and eliminate the cause of its "death" and although this task may be quite difficult, it will save you from the possibility of a quick re-replacement.

The bulk of the commercially available control units were once in use, and after failure, they were simply restored at the manufacturing plant, which, by the way, is much more profitable than creating a part from scratch. Of course, not all broken mechanisms are subject to a restoration procedure. So, for example, an ECU from a "drowned man" that has been covered with water for a long time, most likely no one will repair it.

Despite the fact that in terms of external parameters (shape, size, the same arrangement of contacts), electronic control units may look exactly the same, their settings will still be seriously different. This is not surprising, because they are all responsible for the operation of the engines of cars of different brands, produced at different times. If you install the wrong ECU model, the vehicle may even go, but none of its systems will work stably. That is, it is necessary that the replaceable electronic unit fully corresponds to the broken one. Therefore, when buying an ECU, you need to know the brand of the vehicle, the year of its manufacture, the engine size and the code indicated by the manufacturer on the block.

Each electronic control unit has a microcircuit "PROM", in which all the settings of the systems of this vehicle are saved. Most often, when replacing an ECU, it is simply rearranged from the old unit to a new one, and in more modern vehicle models, instead of a microcircuit, they use flash memory or EEROM- a rewritable storage device.

When installing the unit, the main task is to connect the device to the wiring of the machine, using the appropriate connectors for this. The difficulty in this matter mainly lies in the inconvenience of the location of the ECU, which makes it difficult to get to it. However, before attempting any wiring, it is important to remember to disconnect the battery terminal.

Many electronic control units, after connecting the wires, taking into account the parameters of the vehicle, require additional adjustment. In each case, this process is individual and should be described in the vehicle's service manual. Only specialists from authorized service centers can perform the reprogramming procedure, also called "chip tuning".

Before contacting them for help (handing over the ECU for repair or tuning), you should have some data about your car. First of all, based on the registration certificate or technical passport of the vehicle, determine its brand, model, year of manufacture, name (letters in front of the number), engine size, type of transmission (manual or automatic). Next, remove the device and write down the manufacturer's name and catalog numbers from its label. All this information will need to be communicated to the service center employees who will deal with the elimination of the problem that has arisen.

A modern car is partly a computer on wheels, or to be more precise, a computer that controls the movement of the wheels. Most of the mechanical parts of the car have long been supplanted, and if they remain, then they are completely and completely controlled by the "electronic brain". Of course, it is much easier to drive a computerized car, and the designers think about the safety of such cars first of all.

However, no matter how perfect the design of electronic control units (ECU) is, they can still fail. The situation is not the most pleasant, and due to the complexity of the device, there is no need to talk about self-repair (although there are such craftsmen). In today's article we will talk about what kind of malfunctions can happen to the ECU, how they can be caused and how to diagnose them correctly.

1. Reasons for ECU failure: what should you be prepared for?

First of all, an electronic control unit for a car, or simply, is a very complex and important computer equipment. In the event of a malfunction of this device, incorrect operation of all other automotive systems may appear. In some cases, the car may stop working altogether, including the failure of the transmission, chargers and control sensors.

Electronic blocks are different and can control different devices. At the same time, all systems still actively interact with each other and transmit important information for adjusting all functions. The most basic of these is the car engine ECU. Despite its constructive simplicity, it performs a lot of complex tasks:

1. Control of fuel injection into the combustion chamber of the vehicle.

2. Throttle valve adjustment (both while driving and while the engine is idling).

3. Ignition system operation control.

4. Exhaust gas composition control.

5. Valve timing control.

6. Coolant temperature control.

Speaking specifically about the engine ECU, all the data it receives can also be taken into account when the anti-lock braking system is working, and when the passive safety system is working, and in the anti-theft system.

The reasons for the failure of the ECU can be very diverse. In any case, this does not bode well for the car owner, since this device cannot be repaired. Even at service stations, they simply change it to a new one. But, be that as it may, it is necessary to understand in great detail what can cause a breakdown. Thanks to this knowledge, you will be able to ensure the maximum possible protection of your device from such troubles in the future.

As noted by auto electricians, most often the ECU fails due to overvoltage in the electrical network of the car. The latter, in turn, can occur due to a short circuit of one of the solenoids. However, this is not the only possible reason:

1. Damage to the device can occur due to any mechanical impact. It can be an accidental shock or very strong vibrations that can cause the appearance of microcracks in the ECU boards and the soldering points of the main contacts.

2. Overheating of the block, which most often occurs due to a sharp temperature drop. For example, when you are trying to start the car at high revs in severe frost, squeezing the maximum out of the capabilities of the car and all its systems.

3. Corrosion, which can occur due to changes in air humidity, as well as due to the ingress of water into the engine compartment of the car.

4. Moisture penetration directly into the control unit itself due to depressurization of the device.

5. Intervention by strangers in the device of electronic systems, as a result of which a violation of their integrity could occur.

If you wanted to "light a cigarette" from the car without first turning off the engine.

If the terminals were removed from the car battery without first turning off the engine.

If the terminals were swapped while connecting the battery.

If the starter was turned on, but the power bus was not connected to it.

However, whatever the cause of the ECU malfunction, any repair work can be carried out only after a full professional diagnosis has been carried out. In general, the nature of the device malfunction will tell you about malfunctions in other systems. After all, if they are also not eliminated, then the new control unit will burn out in the same way as the old one. That is why, in the event of an ECU burnout, it is very important to establish the true cause of the breakdown and immediately eliminate it.

But how can you determine that the control unit has really failed, and not some other system? This can be understood by a number of the very first signs that may appear in such a situation:

1. The presence of obvious physical damage. For example, burned out contacts or conductors.

2. Inoperative control signals for the ignition system or the gasoline pump, the idle mechanism and other mechanisms that are under the control of the unit.

3. Lack of indicators from different sensors monitoring systems.

4. Lack of communication with the diagnostic device.

2. How to check the ECU: practical advice for motorists who do not want to go to the workshop.

Fortunately, even if you have neither the money nor the desire to go to the service station, and the ECU does not want to give any signs of life, there is a sure way to determine what is the cause of the breakdown. Perhaps this is due to the presence of a built-in self-diagnosis system on each vehicle control unit. It allows you to determine the possible cause of a breakdown without the use of special diagnostic equipment.

But let's make a small digression and talk about some of the features of the car engine control unit. This electronic device is a mini-computer capable of performing assigned tasks in real time. At the same time, all specialized tasks can be divided into three categories:

1. Processing and analysis of signals that come to the unit from all sensors.

2. Calculation of the required impact, which is necessary to control all vehicle systems.

3. Control over the operation of executive mechanisms, that is, those to which a signal is supplied from the control unit.

However, in order to be able to check the state of the engine control unit, first of all, it is necessary to perform a number of manipulations in order to connect to it. To do this, you will need either a special tester, which, for obvious reasons, not everyone has, or a laptop with a special program pre-installed on it. What kind of program should it be? It is designed to read diagnostic data from the control unit. You can install it either from the Internet or from a disc purchased at the car market.

However, it is worth considering that different models of control units can be installed on different car models. Based on this, it is necessary to select a diagnostic program for the laptop and, of course, the test method itself. We will tell you how to diagnose the model. ECU Bosch M7.9.7. This ECU model is quite common both on VAZ cars and on foreign cars.

As for the diagnostic program, in this case we will use KWP-D. Immediately, we note that, in addition to the program itself to perform diagnostics, you will definitely need a special adapter capable of supporting the KWP2000 protocol. From its connection, the diagnostic process itself begins:

1. We insert one end of the adapter into the port of the electronic control unit, and the other into the USB port of your laptop.

2. We turn the key in the car ignition and run the diagnostic program on the laptop.

3. Immediately after starting, a message should appear on the laptop display confirming the successful start of error checking in the operation of the electronic control unit.

5. Pay attention to the section called DTC, since it is in this section that all the faults that the engine will issue will be displayed. Errors will appear in the form of special codes, which can be deciphered by going to a special section called “Codes”.

6. If not a single error appears in the DTC section, then you can rejoice - the car's engine is in perfect condition.

However, it is also not worth ignoring other partition tables, since they also contain very important information that can explain ECU malfunctions. Among them:

UACC section- it displays all the data characterizing the state of the car battery. If everything is in order with this device, then its indicators should be in the region from 14 to 14.5 V. If the indicator obtained as a result of the test is below the specified value, you should carefully check all the electrical circuits that leave the battery.

THR section- the parameters of the throttle position will be displayed here. If the car is idling and there are no problems with this element, this section will display a value of 0%. If it is higher, contact a specialist for help.

QT section Is the control of fuel consumption. Since the car is idling, an indicator should appear in the table, which is in the range from 0.6 to 0.0 liters per hour.

LUMS_W section- the condition of the crankshaft during rotations. During normal operation, its value should not exceed 4 revolutions per second. If the number of revolutions is greater, it means that uneven ignition occurs in the engine cylinders. In addition, the problem may be hidden in high-voltage wires or candles.

3. What is needed to check the ECU, or how do professionals cope with this task?

Without special equipment, it is simply impossible to carry out a full check of the vehicle engine control unit. But thanks to its presence, the diagnostic process becomes a very simple task. The only problem is to get this special equipment, which, in fact, will do all the work for you.

So, what might a driver need to diagnose an electronic control unit? First of all, it is oscilloscope... With its help, you can get data on the operation of absolutely all vehicle systems. In this case, all received data will be displayed either graphically or numerically.

After removing the numbers obtained from your car, you will need to compare them with the standard indicators. Based on this, you will be able to determine in which system there is a malfunction, and you will be able to fix it. The only disadvantage of the oscilloscope is its cost, which is far from affordable for everyone.

But in addition to the oscilloscope, a special motor tester. Its main function is to determine indicators that come from all electronic systems of an automobile engine. For example, it allows you to determine the drop in revolutions when the cylinders are turned off, as well as the presence of vacuum in the intake manifold. But it costs no less than an oscilloscope.

Since the ECU does not fail so often, and it is still better to entrust the troubleshooting of this unit to specialists, the purchase of such expensive devices is not always a rational decision. Moreover, you yourself will not always be able to correctly read information from their display. Therefore, in case of any signs of a malfunction of the ECU, we recommend that you seek help from specialists. After all, with your manipulations, you can do more harm than good to your car.

Today we'll talk about how to replace the engine control unit on a VAZ 2110-2112 car and where this electronics part is generally located. For those who are not in the know, "brains" are the main element in the ECM, which is responsible for the entire cycle of fuel supply to the combustion chamber and controls all the processes of the engine.

Location of the control unit on the VAZ 2110-2112

So, the "brains" are located directly under the dashboard, namely in its lower part. To get to them, it is necessary to remove the plastic panel from the passenger side, which is shown in the photo below, using a Phillips screwdriver for this:

And in the depths of this whole heap of wires and relays with fuses, you can find the controller itself, which is screwed horizontally on the bar:

Now, below we will consider the procedure for removing and installing the controller.

Dismantling and replacing the ECU on VAZ 2110, 2111 and 2112 cars

So, the first step is to disconnect the minus terminal from the battery. Now, it's worth noting that you need the following tool to do this simple job:

1. Socket head 10
2. Ratchet handle
3. Phillips screwdriver

When we got to the engine control unit, it is necessary to disconnect the plug with the wiring harness from it, after opening the metal latch:

Now you need to unscrew the two nuts securing the "brains", as shown in the photo below:

When these two nuts are unscrewed, it is necessary to slightly move the bar to the right to release it from its engagement:

Then you can carefully remove the ECU:

It is worth noting that if the controller fails, the new one must be installed the same as before - from the factory. The price of new controllers can range from 4,500 to 10,000 rubles, depending on the type and year of production of the car. Installation is carried out in reverse order.

An integral part of modern cars is considered electronic engine control unit... It is designed to receive information from a set of sensors and its subsequent processing. The processed information receives a certain algorithm, with the help of which there is a control effect on various motor systems.

Electronic engine control unit (ECU) - how does it work?

The use of this device effectively optimizes such parameters as power, fuel consumption, torque, content of harmful substances in exhaust gases, and others. The design of the electronic unit includes two main types of support. With the help of hardware, various electronic components are included in the work, led by a microprocessor.

The information from the sensor is converted into digital signals. For this, a special converter is used. The software includes functional and control computing modules. They process the received signals and send them to control the executive devices. In addition, output signals are generated that can be corrected up to a complete stop.

If necessary, the electrical control unit can be reprogrammed. This happens with significant changes in the engine design, for example, when carrying out tuning. A special bus is used for data exchange, with the help of which all control units are combined into a single system.

Repair of engine control units - how to handle it yourself?

An electronic diesel engine control system is installed on almost all modern engines of this type with various fuel injection systems. Such electronic control is intended mainly to regulate and optimize their work. This ensures efficient operation of the entire fuel system, turbocharging, intake and exhaust systems, as well as cooling and exhaust gas recirculation systems.

All electronic control consists of the main unit, input sensors, as well as the actuators of the engine systems. Often, many motorists may be faced with the need to resolve such an issue as repairing an electronic engine control unit. The possibility of carrying out such repairs independently is considered relevant.

From the outset, it is important to find out exactly the name of the block, in the event that the required output parameters are not available. Mainly the device is used ECU, translated as "electronic control unit". With its help, work is carried out in accordance with the input signals of the sensors, which create output signals that control the actuators.

Causes of breakdowns and repair of the engine control unit

Repair of electronic engine control units may be necessary in the absence of uninterruptible power supply. In this case, it is easy to assume an internal malfunction that requires mandatory repair. The reasons may be:

• lack of data exchange with the scanner and the message of incorrect parameters;
• the control lamp "Check" does not light up when the ignition is on;
• for one of the faulty elements, an error message is issued.

In addition, the engine may not work correctly, with deviations, but information about this is not issued.

Timely repair of engine control units will help to avoid many serious problems. In modern cars, so many systems are closed on this device that in the event of any malfunction of the unit, the operation of the entire mechanism or its individual components and assemblies can completely stop. So, we find the culprit of this discussion, the location of which can be clarified in the owner's manual for the car, and we see that it is entirely electronics. How to find the problem and solve it in such a variety of circuits, transistors and other small elements?

There can be at least two reasons why the ECU issues errors or does not respond to the readings of any sensors: the conductor has become unusable or the firmware has gone out of order. It is impossible to restore the firmware on your own if you do not specialize in this area, therefore only a dealership will help. But you can easily check the electrical parameters if you have a multimeter at hand. To know which wires to check for breakdown, you need to master reading the circuitry of your ECU.

One of the most important components of a modern vehicle is the electronic control unit for the engine system. This element receives information from control devices and transforms them into subsequent action. Thanks to the electronics, the active components of the engine are influenced. The element transforms the received information, normalizing the functioning of the car engine. To identify malfunctions and further actions with the control component, consider its structure and principle of operation.

Engine control unit, components and operating principle.

The engine control unit is a complex element that normalizes the most important characteristics of the system. Thanks to this device, the optimal consumption of the fuel mixture and the correct torque of the engine components are ensured. In addition, the engine control component controls the amount of harmful substances in the exhaust mixture and performs many important functions in the operation of the car.

The electronic control unit contains two types of engine support. The hardware part of the component controls electronic devices and auto devices. This action is supervised by a special processor as part of the element.

The indicators of the sensors are given a numerical form. The converter is responsible for this process. The software component of the component contains calculation modules - controlling and functioning. These elements receive and transform the received information. After converting the signals, they are sent to the executive elements of the system, which normalize the function of the motor. At the output, the signal is processed up to a certain action. Thus, if the engine function is incorrect, due to the corresponding signals, the car motor completely stops.

The engine control unit has the necessary software installed by the manufacturer. In the event of a vehicle upgrade, the ECM must be re-programmed. This action is carried out taking into account the reconstruction of the engine and individual features. Parts of an element make up an interacting system. The exchange of information takes place through the connecting bus. Thus, a set of components represent a system that controls the function of a car motor.

Every modern car is equipped with an engine control system. The engine control unit receives the function of optimizing the operation of the most important part of the car. Adjustment and tuning of individual components of the propulsion system, for the correct operation of the machine, is carried out by the electronic engine control unit. Thanks to the element in question, the most productive operation of the engine occurs and the prevention of premature wear.

The engine control unit is responsible for the operation of the following aggregates:

• Fuel supply system.
• Cooling of working elements of the engine.
• Intake and exhaust system.
• Exhaust gas exhaust.
• The control of the propulsion system is assigned to the central control unit.

By adjusting the actuators, the most correct operation of all systems is ensured.

Diagnostics.

Like any electronic device, the element in question often fails. Every motorist may be faced with the need to repair the control unit. With sufficient experience and relevant knowledge, an independent reconstruction of the element is possible, but in most cases this issue is passed on to professionals. To successfully diagnose and identify the causes of the malfunction, you need to know the model of the element - installed on your car. A detailed description of the technical features of the device can be found in the accompanying manual.

Let's consider the main reasons for the device malfunctioning.

Most often, the electronic control unit undergoes reconstruction, with a regular power failure. In this case, a component breakdown may occur, requiring timely elimination. Among the factors that indicate a malfunction, the following can be distinguished:

• Disruption of information exchange, in connection with which - the correct operation of the control device is disrupted.
• Indicator not working when the ignition is turned on.
• The control sensor shows an error. This fact can be detected when one of the elements of the adjustment device breaks down.

Not always, engine malfunction is accompanied by corresponding sensor readings. Therefore, if errors are detected in the operation of the engine, it is necessary to diagnose the electronic control unit in a timely manner.

The most common causes of device breakdown are:

• Violation of the tightness of the conductors. Due to this malfunction, the voltage in the system changes and the control element begins to work incorrectly.
• The firmware of the block has lost.

It is very problematic to restore the firmware on your own. For this, you must have a certain set of knowledge and good experience. But you can check the wiring using a special device. If checking the conductors did not give answers to the question, you need to contact the professionals to restore the software part.

Happy diagnostics!