DIY vaz ecu repair

In detail: do-it-yourself repair of ecu vases from a real master for the site my.housecope.com.

The engine control unit (ECU) is the brain center of the entire car, it consists of a large number of the most complex connections. With the help of this device, the functions of all elements of the power unit are monitored and coordinated.

Control devices installed on various car models are made of high quality materials, high technologies are used in their manufacture, ensuring high-quality assembly of electronic circuits.

But even the highest quality ECUs are prone to breakdowns and often need urgent repairs.

The design of the ECU is divided into main parts: the main unit, control sensors, actuators of the engine elements. The electronic control includes many special elements:

Malfunctions of the engine control unit lead to an imbalance in the operation of all vehicle systems.

The ECU uses the signals sent by the sensors installed on the powertrain to adjust the composition and amount of fuel entering the engine. In the course of its activity, the engine operating mode is set and the exact dosage of fuel mixtures takes place.

As a result of the controller functioning, the engine operation is stable both in cold and after warming up. It is impossible to start the motor if there is a breakdown in the ECU or if its control signals are absent.

Powerful transistors that are part of the control unit control the operation of the following actuators of the engine and fuel system:

ignition coils of the injection system;
idle speed valve;
electric nozzles;
fuel tank ventilation valve;
electromagnetic coils - solenoids;
turbocharging;
intake-exhaust system;
recirculation of exhaust gases;
cooling system.

Video (click to play).

The electronic device is an integral part of the on-board equipment of the machine; it is in constant information communication with such important systems:

Anti-blocking system.
Automatic transmission.
Stabilizing system.
Vehicle security system.
Cruise control.
Climate control.

When using this device, the most important parameters are optimized:

fuel consumption;
engine oil consumption;
power characteristics;
torque that affects the acceleration of the car;
the amount of toxic components in the exhaust gases.

The sensors send information to the controller in the form of digital signals. The control and functional calculation modules included in the software analyze the sensor signals and correct the operation of the actuators. Output signals during the adjustment process can even bring the diesel engine to a complete standstill.

When making significant changes in the design of the power unit (tuning), it is possible to reprogram the electronic engine control unit.

The integration of all control units into a common system is carried out using a special bus.

Situations often arise when car owners are faced with the need to repair the engine control unit. Carrying out this type of work with your own hands is possible with certain qualification skills.

Malfunctions in the operation of the control device occur due to a violation of contacts with sensors that monitor the functioning of the engine's working systems:

Anti-lock braking system (vehicle braking control).
Ignition block.
Injector controller.
Throttle position.
Temperature range of the engine.

Mechanical damage, water ingress on the parts of the microcircuit, failed attempts to repair the device with your own hands also lead to breakdown of the electronic control unit.

Loss of contact with the sensors occurs due to the lack of electricity, which indicates the occurrence of an internal malfunction that requires mandatory repair. Signs of lack of contact can be the following:

data is not received from the scanner;
messages contain incorrect parameters;
the control lamp "check" does not light up when the ignition is turned on;
lack of information about unstable engine operation.

Timely identification of defects and repair of electronic engine control units will prevent a stop in the operation of systems, assemblies, and vehicle assemblies.

The list of the most likely causes includes the following factors:

Microcracks in the circuits and body of the device caused by mechanical stress (shock, strong vibration).
A sharp rise in temperature, leading to overheating of the motor control unit.
Destruction of ECU elements under the influence of corrosion.
Penetration of moisture into the controller case due to depressurization.
Illiterate repair actions.
Applying the "lighting" effect while the engine is running to help the neighboring car.
Changing the position of the terminal connections while connecting the battery.
Lack of power bus connection when the starter is turned on.

The efficiency of the ECU fully depends on the listed factors, many of which are capable of causing significant harm to the control device.

To prevent permanent damage, it is necessary to carry out regular diagnostics of the electronic engine control. In order to save on expensive repairs and complete replacement of elements of the electronic control system, the check is carried out at least once a year.

Malfunctions in the engine control unit are indicated by the following vehicle malfunctions:

problems with starting the engine;
tripping the engine;
the appearance of thick smoke;
decreased response to the gas pedal;
interruptions in connection with the ECU;
loss of control over turning on and off the engine fan;
malfunctions of the ignition coils;
failure of fuses;
sensors are not sending signals.

Thanks to the self-diagnosis system built into the ECU, you can check and determine the degree of damage with your own hands. To carry out diagnostic measures, you need to connect to the device using a laptop with an installed program designed to work with diagnostic data. Instead of a laptop, you can use special testers, oscilloscopes.

The data obtained during the measurements are compared with the indicators that are standard.

The causes of damage to the engine control unit are divided into two main types: faulty conductor or firmware failure. The firmware is restored only with the help of specialists in the service center. You can check the electrical parameters with your own hands using a special measuring device - a multimeter.

To search for a breakdown in the wire, you must familiarize yourself with the control device diagram. Having studied the location of the conductors, resistors and power supply, it is the turn of the "continuity" of the electrical circuit in the place where the error in the readings of the electronic unit is detected. In the absence of such information, it is necessary to check the wires throughout the circuit.

To repair the engine ECU, the following operations are required:

Locate the breakdown location.
Re-measure the resistance.
Find the attachment points of the conductor.
Attach in parallel a wire with the required resistance using a soldering iron; it is recommended to leave the old wire in place.

After the measures taken, the system should work stably. If the ECU errors repeat, contact the service center.

The durability, safety and reliability of the vehicle depend on the timeliness of the repair of the engine control unit.

The electronic engine control unit is rightfully considered one of the most important parts of the car. This device is not in vain called the "brains" of a car, because it is entirely responsible for the stability of the operation of almost all vehicle systems.

Every year more and more cars appear on the world market, the reliability and durability of which directly depends on electronic systems. Absolutely all manufacturers are trying to equip cars with the latest ECU models. Along with this, the mechanical components in the car are becoming less and less.

Be that as it may, the use of electronics in the automotive industry is fully justified. ECM manufacturers place great emphasis on the quality of materials and the assembly of their products. That is why the “brains” of a car are extremely rare. But as they say, nothing lasts forever. And even a high-quality ECU will fail sooner or later.

In a wide range of specialists, a list of the most common reasons for which an ECU breaks has long been compiled. These include:

mechanical damage. The engine control unit is damaged from shocks and strong vibrations, which contribute to the appearance of microcracks in its circuits and housing;
sharp jumps in temperature, as a result of which the engine control unit itself overheats;
corrosion;
depressurization and ingress of moisture into the ECU case;
interference in the work of a block of people who do not have the necessary skills;
the so-called "lighting" from a car with a running engine;
rearrangement of terminals when connecting the battery;
starting the starter without a connected power bus.

All of the above factors affect the efficiency of the engine control unit in different ways. Some of them cause minor harm to the “brains” of the car, while others can instantly break the block. Fortunately, there is still a way to prevent the final breakdown of the unit - ECU diagnostics, which should be performed at least once a year.... This is the only way to save on expensive part repair or complete replacement.

Many drivers believe that only professionals should be engaged in checking the operation of the engine control unit. In fact, almost every “brain” at the factory is equipped with a built-in self-diagnosis system. With its help, it will not be difficult for even an inexperienced driver to identify any malfunctions with their own hands.The engine control unit is a mini-computer that must perform specialized tasks in real time. The latter can be divided into 3 categories:

processing signals from sensors;

calculation of impacts to control vehicle systems;

adjustment of the operation of executive mechanisms.

To start checking the status of the engine control unit, we need to connect to it. This can be done using a special tester or laptop. On the latter, a program designed to read diagnostic data must be installed in advance. Modern cars are equipped with various ECU models. We will consider the implementation of diagnostics of the engine control unit using the model as an example Bosch M 7.9.7... These are the “brains” that are installed on the latest car models. VAZ and many foreign cars. Image - DIY ecu vaz repair

We will carry out diagnostics with our own hands using a free program KWP-D... In addition to the utility, we need an adapter that supports the protocol KWP2000... We start diagnostics by connecting the adapter. We insert one end of it into the ECU port, and the other into the laptop. After that, turn on the car ignition and start the program. A message should appear on the laptop display stating that the operation to check for errors in the operation of the ECU has begun successfully.After that, we will see a table with the most important parameters of the machine.

It is necessary to pay attention to the DTC section, which contains all the errors issued by the engine. If there are any, then go to the "Codes" section, where we will see the decryption of all existing failures. If you did not find any errors, then the engine is in perfect condition.

Other sections of the table should not be ignored either. The information in them is equally important. So, the UACC parameter is responsible for the state of the battery. Normal readings for this section are in the range of 14-14.5 V. If the voltage of your battery is less - it is worth carefully checking the electrical circuits. Another important parameter is THR, which is responsible for the position of the throttle valve. During normal idling, the throttle position sensor will read 0%. Otherwise, you should contact a specialist.

Another important indicator that interests all drivers is the QT parameter, which is responsible for the amount of fuel consumption. At idle speed, the section should contain figures of 0.6–0.9 l / h. For a more accurate diagnosis, you will need to check the voltage in the car spark plugs. When checking all these indicators, drivers very often ignore the state of the crankshaft during rotation, for which the LUMS_W section is responsible. If the numbers in it are more than 4 rev / s, this is a sign of uneven ignition in the cylinders. It is also worth checking the high voltage wires and candles.

Diagnostics and repair of ECUs is not at all difficult. However, as with any business, you should always be prepared. In the case of a brain test, it will be enough for us to purchase inexpensive devices. They will help you do all the work yourself. The first thing every driver needs to have is an oscilloscope. This device provides the necessary information about the operation of all vehicle systems. Image - DIY ecu vaz repair

The received data is displayed in numerical or graphical form. With the help of an oscilloscope, we can compare the available numbers with standard indicators. The cost of the device is in the region of 2-5 thousand rubles. Another important device is the motor tester. It is designed specifically to determine the performance of electronic engine systems. With its help, you can get information about the drop in revolutions when the cylinders are turned off and the discharge in the intake manifold. The price of the device ranges from 3 thousand rubles.

Do you still think that car diagnostics is difficult? If you are reading these lines, then you have an interest in doing something yourself in the car and really savebecause you already know that:

STO lomat big money for simple computer diagnostics

To find out the error, you need to go to the specialists

Simple wrenches work in the services, but you can't find a good specialist

And of course you are tired of throwing money away, and there is no question of driving around the service station all the time, then you need a simple ELM327 AUTOSSCANER that connects to any car and through a regular smartphone you will always find a problem, pay off CHECK and save a lot.We have tested this scanner ourselves on different machines. and it showed excellent results, now we recommend it to EVERYONE! So that you do not fall for the Chinese counterfeit, we publish here a link to the official website of the AutoScanner.The ECM is the brains of the vehicle. With its help, the main processes that ensure the normal operation of the power unit are produced and controlled. You can learn more about how diagnostics, as well as home repairs, of the engine control unit are made from this material.Before you repair the engine control unit in your car, you need to be sure that the manifestation of breakdowns is associated precisely with its work. According to many of our compatriots, the repair of electronic engine control units should be carried out by specialists.But do not forget that almost all ECUs are equipped with a self-diagnosis system, which allows you to easily identify system malfunctions. Image - DIY ecu vaz repair

Repair of the motor control unit

To diagnose the ECU with your own hands, you will need to connect to the device, for this you will need a special tester or computer. If you are using a laptop, you must install the appropriate verification software on it in advance. On many domestic VAZs, as well as foreign cars, a Bosch engine control unit is installed, using this device as an example, you will consider the verification procedure. For diagnostics, you need the KWP-D utility (you can use any other, we took this one as an example). In addition to the program, prepare an adapter that must support the KWP2000 protocol.

The diagnostic procedure begins with connecting the adapter - one of its outputs must be connected to a port on the unit, and the other to a computer.
Turn on the ignition and run the utility. A message appears on the computer screen to start the error checking procedure.
Further, you can see a table in which the main parameters of the car's functioning are marked. Pay attention to the DTC category, all errors that are in the operation of the machine's motor are marked here. If they are present, then in the "Codes" section you can decipher these errors.

You also need to pay attention to other sections. For example, the UACC indicator is responsible for the functionality of the battery - ideally, its parameters should correspond to 14-14.5 V. If the voltage level is lower, it is necessary to diagnose the wiring. The THR parameter is responsible for the performance of the choke, if the device is working normally, then it should be 0%. The QT parameter is responsible for the volume of fuel consumption, at idle this indicator should correspond to 0.6-0.9 liters per hour (the author of the video is the AlexBrooy channel).

Repair of vehicle control units should be carried out in the event of a malfunction.

Before removing and disconnecting the faulty ECU, let's look at the main causes of breakdowns:

Repair of the engine ECU can be carried out in the event of mechanical damage. The brains of a car can be subject to vibration and shock, as a result of which cracks can form on the body of the device and the board.
Temperature differences can also be the cause of a car's ECU malfunction, which contributes to overheating of the device.
Corrosion and exposure to aggressive environments on the device.
Moisture - if it enters the housing, it may require replacement of the vehicle ECU. Often it is not possible to make repairs after moisture has entered the structure. The reason for the ingress of moisture into the device may be the depressurization of the housing elements.
As experts note, quite often the need for repair arises as a result of interference in the work of the "brains" of inexperienced repairmen.
Lighting the battery from the car with the engine running.
Replacing the engine control unit may be required if the “+” and “-” terminals were swapped when connecting the battery.
Another reason is the inclusion of the starter in the absence of a power bus connection (video by Ramil Abdullin).

We will also consider the signs of a malfunction of the car's ECU, which will allow us to determine the breakdown of the device:

The engine does not start, smokes, possibly knocking.
Motor skips.
Dips, when you press the gas pedal, the car may not respond.
There is no connection with the "brains".
The control lamp of malfunction of the engine management system is on. It may be a Check Engine light, but in some cars, the unit health indicator is used separately.
The cooling fan turns on randomly.
The safety elements burn out regularly.
Controllers and sensors stop signaling.

Before removing the control unit and disassembling it, inspect the connector of the device, it may be damaged.

The repair procedure is described using the example of a BMW ECU:

How to replace the engine control unit with your own hands - see the video below (video by Sergey Kitaev).

We check the ECU with our own hands
1. Reasons for ECU failure: what should you be prepared for?
2. How to check the ECU: practical advice for motorists who do not want to go to the workshop.
3. What is needed to check the ECU, or how do professionals cope with this task?

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.

First of all, an electronic control unit for a car, or simply an ECU, 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 during the operation of the anti-lock braking system, and during the operation of the passive safety system, 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 when 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.

Fortunately, even if you have neither the money nor the desire to go to the service station, and the ECU does not want to show 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.

4. Next, the screen will show a table with the most important parameters of the car's functioning indicated in it.

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 check 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.

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.

As you know, a modern injection engine is fully controlled by an advanced ECM. The system includes blocks-controllers, sensors and executive electronic-mechanical devices. In this case, different control units are used for different engines.

Although these blocks are quite reliable devices, their breakdown cannot be ruled out. A short circuit, mechanical damage to the unit, ingress of moisture into the controller, etc. can lead to problems that are directly related to the ECU. One way or another, incorrect operation of the control unit will not allow the internal combustion engine to operate normally.

In such a situation, the "brains" are changed to a suitable analogue, after which the engine control unit is flashed. In this article, we will talk about how to replace an ECU with an engine with your own hands.

To begin with, in the event of a failure of the control unit, this device must be changed, since repairs are often impractical. Given the high cost of the device, it is often practiced to replace it with a used control unit, less often a new computer is purchased.

In this case, for replacement, special attention should be paid to the selection of the control module. The control unit must not only be suitable for the model, but also correspond to one or another type of engine. In other words, most often the ECU only fits from a similar car model with exactly the same internal combustion engine.

The electronic unit monitors the operation of the ignition system, fuel injection, evaluates the composition of the exhaust gases, etc. In each car model, an on-board computer is individual for a specific type of vehicle.

As mentioned above, the need to replace the engine control unit may arise for various reasons. In most cases, failures in the control unit do not allow the car to be operated normally, as a result, the ECU needs to be replaced.

Taking into account the fact that the engine control unit is an electronic device, its high sensitivity to voltage drops in the on-board network and short circuits was noted. Also, moisture is not allowed to enter the ECU housing. Another unit may fail due to increased vibrations, shocks, etc.

By the way, among the most common reasons for the failure of the on-board computer is still a voltage drop, that is, a short circuit in the car's electrical circuits. We also add that in case of obvious problems with the battery or generator, when the voltage is simply not enough, the ECU may also start to malfunction.

Also, within the framework of diagnostics, it is very important to determine the very reason that led to the failure of the controller. Please note that if the cause is not found, then replacing the motor control unit may re-result in a breakdown of the newly installed device.

It is important to understand that engine malfunctions are often not associated with the ECU itself. Failure of ECM sensors, incorrect operation of actuators, breakdowns of the power unit itself and other reasons do not allow the unit to ensure stable operation of the power plant.

As for the unit itself, at the initial stage, the voltage on the ECU is checked. Then diagnostic equipment is connected to the unit, operability is tested, input and output signals are tested. Only the tests carried out in the complex allow us to conclude that the control unit is inoperative and needs to be replaced.

Now let's move on to the replacement itself.Please note that replacing an engine control unit can be difficult if the necessary skills are not available. As a rule, the ECU needs to be found first. In other words, you should know where the ECU is on the car, depending on the make and model of the vehicle.

The fact is that manufacturers do not always install ECUs in an easily accessible place. There are many reasons for this, ranging from protecting the control unit from vibration, moisture and temperature extremes, and ending with protection against theft.

In the second case, the main task is to make it difficult to access the device so that the hijacker does not have an easy opportunity to replace the block, bypass the immobilizer, etc. It is quite obvious that the ECU can stand both in the engine compartment and in the passenger compartment. To find the controller, you may need to partially disassemble the passenger compartment, remove attachments from the engine, etc.

After that, you need to check the operation of the ECU, and only then assemble the interior in the reverse order. If the attachment was removed from the engine, you first need to install all the parts and elements back, and only then check the performance of the new unit.

Also, during the test, it is advisable to connect the appropriate equipment to the diagnostic connector. This will ensure that the engine and other systems are operating normally with the new ECU.

By the way, on many cars the unit needs adaptation. In practice, especially when it comes to a car with a solid mileage, this means "self-tuning" of the controller, taking into account the wear of the internal combustion engine, reduced performance of the fuel pump, injectors, etc. It turns out that the engine after replacing the ECU will not reach optimal performance immediately, but some time after the start of the car's operation.

Although the electronic components of many manufacturers are officially non-repairable, specialists often quite successfully restore these devices. This means that the possibility of repairing the ECU should not be completely ruled out either. If the unit is very expensive or rare, then the possibility of repairing the ECU may be a way out of this situation.In the case when all the work is done correctly, additional tuning of the ECU allows you to improve individual technical characteristics of the motor on a particular car. As a rule, the engine starts to “pull” better at low revs, dips disappear when the gas pedal is pressed sharply, the engine works more elastic in different modes, etc.However, one should not forget about the disadvantages of chip tuning. If a program of an unknown manufacturer is installed, the specialists did not “run in” the firmware on the fly, etc., then the engine resource may be noticeably reduced, there are problems with mixture formation, the revolutions may start to float, the engine “dulls”, the responsiveness to pressing the accelerator pedal disappears, under loads the internal combustion engine stalls, etc.For the reasons stated above, flashing the ECU should only be performed by qualified personnel using special equipment. It is important that the software (firmware) is proven and of high quality, after which mandatory adjustments are also made on the fly (the so-called online ECU firmware run-in).