ECU (electronic control unit) is a device that controls the parameters of mechanisms in the process of operation. Usually the abbreviation ECU is used in relation to the engine control unit.
In fact, the car also has brake system control units (ABS unit), a body control unit, which is often referred to as the Body Control Module (BCM or BSI), a climate control unit (climate control) and others.
Principle of operation
The principle of operation of the electronic engine control unit is based on a standard microcontroller architecture. Data on engine parameters from various sensors enter the ECU, then are processed (amplified, digitized, encoded).
The main processing of data according to a certain algorithm is performed by a microprocessor, which gives signals to the actuators via the output bus. These signals are adapted (converted from digital to analog, amplified) and fed to the connectors of the electronic control unit.
Among the tasks solved by the electronic engine control unit is the diagnosis of the operation of the main components. Modern ECUs can detect a variety of errors:
- lack of supply voltage on the electronic components of the engine or reduced power supply;
- breakage of electrical circuits or short circuit;
- incorrect signals at the output of sensors;
- misfiring and injection;
- mismatch of ignition angles;
- and many others.
Errors are stored in non-volatile memory until they are cleared using diagnostic devices (active errors cannot be deleted without eliminating the cause of the error).
In cars of earlier years of production, errors could be removed by temporarily (about 15 minutes) disconnecting the battery from the car's on-board network.
The ECU, together with the immobilizer, blocks the operation of the engine in case of unauthorized access. Each electronic engine control unit performs this function in accordance with the algorithm laid down by the manufacturer.
Can be blocked:
- ignition signal to the coil;
- fuel injection pulses;
- permission to start the starter, etc.
In some vehicles, the engine may start for a few seconds and stall.
Scheme
The circuit diagram of the engine control unit itself is a trade secret, and it is very problematic to find it even for domestic cars.
Therefore, ECU repairs are carried out only by high-level professional electronics engineers. Usually, injection and ignition control transistors, reference voltage stabilizers fail in control units, firmware flies.
Specialists sometimes specifically change the software firmware in order to increase engine response or reduce fuel consumption.
Video - ECU M74 firmware:
To repair the electronic components of the engine, an electrical circuit for connecting the computer is required. Such a scheme can be found in the manuals for the operation and repair of cars, software and hardware systems such as AUTODATA and TOLERANCE.
For example, consider the organization of the engine control circuit for a 2001 Volksvagen Golf 3 car, AEE engine, Magneti Marelli 1 AV control unit.
Without delving into the circuit, you can see that the ECU uses signals from the camshaft, mass air flow, coolant temperature, and oxygen sensors as sensors.
The signal coming from the camshaft sensor has the form:
As actuators, the ECU controls the signals for injection of injectors, throttle actuator, ignition to the coil switch:
The ECU is connected to the immobilizer, dashboard.
In order to check the electrical connections of the circuit nodes with the electronic engine control unit, you need to know the location of the contact pins (pinout), which is also given in the reference books:
Where is the engine control unit
In cars up to the 90s of production, the most rational location for the engine control unit was considered to be the space in the car interior near the left or right front pillar in the area of \u200b\u200bthe passenger or driver's legs. First of all, it was believed that these are the most protected places in terms of mechanical damage and moisture penetration.
Video - ECU transfer on Kalina:
Since the mid-90s, engine control units have been placed in the engine compartment. This is due to the following considerations:
- under the hood it is easier to troubleshoot electrical connections;
- all communications with engine sensors and actuators become shorter, therefore more reliable;
- ECUs have become more reliably protected from moisture with the help of special sealants.
In the absence of reference books, it is not difficult to find the electronic engine control unit by moving along the large wiring harness of the engine control system. It usually represents a small electronic unit in a metal casing with one or more connectors at the end.
In many cases, getting access to the internal space of the block to the electrical circuit is not easy: it is flooded with compounds that must be removed. The board usually contains a small number of components.
ECU symptoms
There is an opinion among auto electricians that the electronic engine management system fails last. Moreover, they can not always determine the malfunction of the engine control unit.
Indeed, the ECU can diagnose the nodes connected to it, but in most cases it cannot diagnose its own performance.
What can indicate a malfunction of the ECU?
The most common symptoms of a malfunction are the constant blown fuses serving the engine control unit. In practice, cases of polarity reversal of the battery connection are not uncommon. The ECU circuit has protective diodes for this case. If they break through, a short circuit occurs in the power supply, which leads to the constant blowing of the fuses. Faulty ones must be changed.
Also, a power failure can cause the battery to disconnect while the engine is running. In this case, the control unit is powered only from the generator and, if it is faulty, a situation may arise that the voltage is incorrectly applied to the unit.
It is impossible to remove the battery terminals with the engine running (!), as many motorists do when starting from someone else's battery.
How to check the ECU for performance
The first stage of the performance check is the control of all supply voltages.
The second stage is computer diagnostics. If the diagnostic device communicates with the engine, this is already a sign of the ECU's operability.
About blocking the block with an immobilizer, then you need to bind the keys.
In some cases, to determine the malfunction, it is necessary to disassemble the computer, that is, remove the sealant and remove the cover, gaining access to the board. It can detect burned-out conductive tracks, faulty transistors, diodes and other elements.
The most reliable way to check is to "throw" a known-good ECU. But it must be either non-immobilized or you will have to “tie up” the keys and the immobilizer again.
Sometimes a set of ECU + immobilizer + key chip is sold at disassembly. In this case, there are no problems. Connect the ECU and the immobilizer to the circuit, install the chip at the end of the pump coil on the ignition switch, and then start the engine.
Additional protection
For more confident protection of the engine control unit from battery polarity reversal, it is possible to install diodes in the supply circuits (better powerful zener diodes with a stabilization voltage of 15 - 17 Volts) in reverse connection.
Then overvoltage and polarity reversal will lead to the failure of the fuses serving the power supply circuits of the computer, increased voltage or reverse polarity voltage will not pass to the control unit, and this is the biggest danger.
In order to protect the computer from climatic influences, it is necessary to monitor the quality of the sealant. After five years of operation, it is advisable to take measures to improve tightness, since the old sealant may dry out at elevated temperatures under the hood.
Video - protection of the Renault Duster engine control unit (Logan, Largus):
You can not block access to the block with additional structures, put rags near it. This reduces the natural ventilation of the device, which heats up during operation of the vehicle.
Replacing the engine control unit
If the control unit is out of order and cannot be repaired, it should be replaced with a similar one with the same number indicated on the computer case.
Sometimes a slight deviation in the number is allowed. For example, a change in the last two or three digits may indicate a different engine size or modification, which may have little effect on technical characteristics.
In any car, an important role is played by repair of electronic control units, as in the event of a malfunction, they can cause the engine to fail. Very often, after repairs in a car service, in case of an accident and other events, the car simply does not start. There can be many reasons for this, and in the most urgent situations, the help of a private specialist with a visit is simply necessary.
A qualified master is the key to solving all problems
A private specialist is a true master of car electronics. Thanks to his many years of experience, he can easily cope with the repair of any electronic control units of any brand of car and even a specific model. Huge experience with various models will allow you to perform repairs quickly and efficiently, unlike all those car services that take a long time with their customers.
A private specialist already knows how to solve the problem, so you can contact him for help at any time and also at any time get high-quality and fast support. The client does not need to wait for his place in the queue - it is important for those who urgently need to go to work, but the car does not start. Just call and all questions will be solved!
Repair of control units, as one of the most popular services
If the car has gone into an unusable state, there is no need to worry and think that the car will not be available for use soon. Nowadays, such issues are resolved very quickly. It is important to note that the visiting master, in addition to work experience and the necessary knowledge, also has the entire arsenal of necessary spare parts and equipment. The client does not have to look for anything on his own - an ambulance is ready to help out in any situation.
The car is saturated with various electronic systems (ECU), including the engine, brakes, navigation, radio, etc., but most often there are problems with the engine ECU. There can be many reasons for this, including:
- voltage failure;
- unsuccessful repair;
- The battery is out of order;
- the car has been in an accident;
- water ingress into the electronic control unit system.
As a result, the driver will face the fact that his car will stop starting. Repair of control units may be required in other ECU systems for the same reasons. If something is not working, but the car is free to continue moving, it is best not to ignore it and fix the problem right away.
ECU firmware Cummens or what is the reason for the constant appeal
Surely every driver thought about the advanced features of his car. This will require a flashing of the engine, but most often the drivers of the new Gazelle apply for such a service in order to go further from the standard settings. This will increase the power of the engine, increase the permissible speed of movement, adjust the starting speed, since the default settings for each engine are too restrictive for the driver in his actions.
ECU firmware Cummens is the only solution to this issue. The process is quite complicated for those who encounter this problem for the first time. To solve it, you will need the help of a real master who will come to the place with his laptop, connect to the computer and make changes to the native firmware of the car engine. It is important to note that only an experienced specialist can interfere with the factory settings, everyone else is afraid to deal with this.
Contacting a private specialist
As you can see, there can be many subtleties and nuances, according to which the problem will only worsen, not be resolved on its own. In such subtle things as a car electrician, only a person with vast experience behind him should understand. The customer should always think about this before taking any action on their beloved car.
The electronic engine control unit is often referred to as brains, motronics, ECU, computer or ECM for example.
The block is responsible for the operation of the engine mainly by adjusting the correct ratio of air and fuel supply to it, however, this seemingly simple process has hundreds of indicators, influencing which the given engine power and the efficiency of the car as a whole are ensured.
By complicating control systems and saving on the production of ECUs, manufacturers thereby reduce its reliability, forcing owners to buy new "auto-brains" or look for those who will repair the computer ICE.
There are thousands of control units, even on a motor with the same hardware, the units are different and not interchangeable, in the photo the engine blocks are from the same type of Mercedes, one engine, but the right one is slightly longer and, of course, it is completely different in terms of filling.
ECU engine diesel engine OM642 taken from the car
In this case, you can’t do without diagnostics, and based on its results, you can roughly understand whether auto electronics repair is needed or if it’s something else. Even if there was an accident or a fire under the hood, the ECU must first be diagnosed on the car and only then carried in for repair.How to determine that the engine needs repair of the electronic unit?
ByA sequence of actions that will help you avoid unnecessary expenses:
1. Track the symptoms. Before electronic diagnostics, external symptoms may indicate malfunctions:
2. Already in the process of diagnosis, more specific defects can be identified:
- instability when starting the power unit
- engine does not start or starts and stalls
- turns the starter, but does not start - does not grab
- excess fuel consumption
- malfunctions of the cylinders, the car troit, the engine does not run smoothly
- engine does not pull or revs
3. If at the previous stage the error codes did not clarify the situation or they simply do not exist, it is necessary to study the malfunction in more detail before repairing or even opening the engine electronic unit:
- lack of communication between the ecu and other units
- errors on the engine pointing to any ICE node
- inability to connect a diagnostic scanner - there is no connection with the brains
- misfiring or no spark or injection at all
- The ECU does not see a signal from any sensor and / or does not control any element
- carry out diagnostics with a more expensive or dealer scanner in which the functionality is much wider than in the Chinese adapter
- study the current values \u200b\u200band know what each indicator affects and whether its characteristic changes (for example, do you have the correct pressure in the rail, air flow and is there enough revolutions to start)
- connect a motor tester or oscilloscope devices that allow you to see several signals in time (for example, the phases of the crankshaft / camshaft sensors and the opening time of the nozzle)
An approximate list of reasons why the Mercedes and VAG group ECU fails:
- improper "lighting" of the car
- jumps in the onboard network
- due to natural wear and tear
- with incorrect firmware or "collective farm" repairs on the knees
- due to water entering the block
- due to oxidation of the contacts in the connectors
- when the electrical wiring or actuator is shorted
This is true for both cars and trucks:
What is important is thatIf you do not eliminate the cause of the malfunction, then it is useless to install a new unit - it will burn out again! Among the defects that led to the repeated breakdown of the ECU are the following: the closure of any sensor on the power supply, short circuit of the wiring or coils, injectors, valves. If the cause is not found, then before looking for a replacementa used engine block at a car dismantling site, or a new one from official dealers, contact the block for repair. It may be possible to identify the cause of the failure of the computer, eliminateput it on the car and then install a new engine control unit with confidence, without fear of re-burning it.
Case from practice:
The owner of a Mercedes faced the following problem: he recently bought a 221 S-class, everything worked, and now the car is troit - it drives normally for part of the day, and then it crashes. Replacing spark plugs, wiring, coils does nothing. The owner passes 4 services and eventually comes to professionals in auto electronics. The result - the problem is in the crooked hands of the "Kulibins", who repaired the electronic engine control unit six months ago. The problems then were similar, but the defect was eliminated, although not permanently, after a couple of months, it reappeared again.
Dangers of intervention in the block. Or how do "kulibins" work?
It is not recommended to apply for car ECU repair to homegrown “Kulibins” who repair everything from cell phones and laptops to complex automotive electronics.There are thousands of versions of internal combustion engine blocks and the engines themselves, it is difficult for a diagnostician to work globally on each in a service, and even simply opening or soldering with Chinese, cheap equipment renders the computer unusable.
They roughly open the block, eliminate only visually visible defects, maximum,they try to find faulty elements like short-circuited transistors or diodes with a cheap tester, but such defects are 15%, and even then, they were found on old ECUs, new boards and chips are protected from fires "in smoke" and visually you will not see anything.
If home-grown craftsmen bring the block to the handle, then they find the cheapest suitable one (at first glance!), For example, using the connectors, the block and try to encode it and make it work - after such experiments, the root cause of the defect cannot be found at all.
Attention is sharpened, because such “generalist” masters do not even know the simple rules for handling complex auto electronics. For example, they do not know about ESD safety, which will lead to static damage to boards and chips, which is more difficult to identify than the root cause of the breakdown.
Both car owners themselves and professionals who are then brought mutilated blocks, sometimes with the impossibility of recovery, suffer from the “Kulibins”.
How is the work of our masters?
In our laboratory, for testing the same transistors, it is possible to use source meters or curve tracers, or more accurate measuring instruments than Chinese multimeters and an oscilloscope. We have our own defect databases, wiring diagrams, research materials on the problems of a particular unit, special debugging programmers and stands for connection, in special cases, high-precision circuit analyzers or high-precision testers are used that notice even small deviations of ECU parameters from the norm.
Professional laboratory of auto electronics
If the ECU is non-repairable, and we have a replacement unit, we select a motronic suitable for replacement numbers and bind it to the machine programmatically, i.e. we transfer all the car data or update the software online to the latest one.
How is the engine control unit repaired?
The results of diagnostics on the car are specified. This is necessary to exclude all kinds of defects and identify a malfunction of the block itself.Diagnostics of the computer itself is done on a special stand - connected "on the table" is testedvarious measuring devices, together with a check by a dealer scanner that reads error codes and current values.
The data obtained is analyzed and a decision is made to repair or replace the control unit. If you can limit yourself to cleaning contacts, replacing software, microcircuits and elements, repairs are carried out quickly. If not, we proceed to an in-depth restoration of the ECU, sometimes already in the factory.
Then electronic engineers are included in the case, each according to their node and defect. They analyze the state of the block, perform troubleshooting and replace faulty chips, processors, passive strapping elements, or solder boards. The ECU is connected to a diagnostic scanner or debugging equipment and flashed.
Technologically repair the engine ECU – tr A daunting task for a master of automotive electronics. Work is 100% dependent on special equipment, experience and professional development of the repairing person.
During operation on the machine, check the condition of the terminals, chips and connectors. The restored block is mounted on a car and each of the systems is debugged, the car is transferred to the owner.
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 almost all vehicle systems.
1
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. Manufacturers of engine control units pay a lot of attention to the quality of materials and assembly of their products. That is why the “brains” of a car fail extremely rarely. But, as they say, nothing lasts forever. And even a high-quality ECU will fail sooner or later.
In a wide circle of specialists, a list of the most common reasons for which the computer breaks down has long been compiled. These include:
- mechanical damage. The engine control unit is damaged by shocks and strong vibrations, which contribute to the appearance of microcracks in its circuits and body;
- sudden temperature fluctuations, as a result of which the engine control unit itself overheats;
- corrosion;
- depressurization and moisture ingress into the ECU case;
- interference in the work of the unit by people who do not have the skills necessary for this;
- the so-called “lighting” from a car with a running engine;
- rearrangement of terminals when connecting the battery;
- turning on 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 damage to the “brains” of the car, and something can instantly break the block. Fortunately, there is still a way to prevent the final failure of the unit - computer diagnostics, which should be performed at least once a year. This is the only way to save on expensive repair of the part or its complete replacement.
2
Many drivers believe that only professionals should check the operation of the engine control unit. In fact, almost every “brain” is equipped with a built-in self-diagnosis system at the factory. With its help, it will not be difficult even for 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 of signals coming from sensors;
- calculation of impacts to control vehicle systems;
- adjustment of the operation of the actuators.
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 a laptop. On the latter, a program designed to read diagnostic data must be installed in advance. Modern cars are equipped with various models of ECU. We will consider the diagnosis of the engine control unit using the example of a model Bosch M 7.9.7. It is these “brains” that are installed on the latest car models. VAZ and many foreign cars.
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 the diagnostics by connecting the adapter. We insert one end of it into the computer port, and the other end into the laptop. After that, turn on the ignition of the car and run the program. A message should appear on the laptop display stating that the operation to check for errors in the operation of the computer has successfully begun. 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 generated by the engine. If there are any, then go to the "Codes" section, where we will see a decoding of all the existing failures. If you did not find any errors, then the engine is in perfect condition.
Do not ignore other sections of the table. The information they contain is just as important. So, the UACC parameter is responsible for the state of the battery. Normal values for this section are in the range of 14-14.5 V. If your battery voltage is lower, you should carefully check the electrical circuits. Another important parameter is THR, which is responsible for the throttle position. During normal idling, it will show 0%. Otherwise, you should contact a specialist.
Another important indicator that all drivers are interested in is the QT parameter, which is responsible for. At idle, the section should contain the numbers 0.6–0.9 l / h. For a more accurate diagnosis, you will need to check the voltage in the car's spark plugs. 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 rpm, this is a sign of uneven ignition in the cylinders. It is also worth checking high-voltage wires and candles.
3
Diagnosing and repairing an ECU is by no means a difficult task. However, as with anything, you should always be prepared. In the case of checking the “brains”, 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.
The received data is displayed in numerical or graphical form. With the help of an oscilloscope, we can compare the available figures 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 for determining the performance of electronic engine systems. With it, you can get information about the drop in speed when the cylinders are turned off and the vacuum in the intake manifold. The price of the device fluctuates within 3 thousand rubles.
Some general information about electronic control units ECU:
The abbreviation E-C-U (read. E-K-U) in the automotive industry means electronic control unit (ECU). Verbatim ECU This Electronic Control Unit (ECU). Modern cars have many different ECUs. They are related to the engine anti-slip and anti-lock braking system brakes, automatic transmission, active suspension, full-time security system, air conditioning, radio and navigation, etc. One of the most important components is it's electronic engine control unit - ECU. Various car manufacturers and various thematic sources, it can correspond to the names ECU, DME, DDE, ECM(Engine Control Module), PCM(Powertrain Control Module) and some other abbreviations ECM (Engine Control Module, often combined with the automatic transmission control unit- Control block PCM). Titles PMS And PLD used in some car engine control units mercedes, issued by companies Bosch and Siemens . Often, for many manufacturers, the engine control unit combined with automatic transmission control unit(automatic transmission) in one case. In this performance, most often it is called PCM(Powertrain Control Module). Such solutions are used Ford, Mazda, Toyota some German and Korean manufacturers.
Let's take a simple example of block PCM from Toyota RAV4 1AZ-FE AT 2002 release, USA. As can be clearly seen in the figure below, Control block PCM/ECM Toyota RAV4 has 2 CPUs - each works independently (at the same time, constantly exchanging data with each other), giving executive commands and processing signals from automatic transmission and ENGINE sensors. The processors control the automatic transmission solenoids and injectors through specialized driver microcircuits.
On the picture : electronic Control block d engine and automatic transmission ECU (PCM/ECM)from Toyota Rav 4 1AZ-FE 2002 year. Part number according to Toyota: 89661-42821. The electronic components for engine and automatic transmission control are combined in one housing on a single printed circuit board. We carry out repair of control units ECU PCM Toyota RAV 4 from 2000 to 2004 release (bumps when shifting gears, solenoids errors) at a special price 6500 rub with a guarantee 6 months.
To avoid confusion with many terms, we will stick standard term ECU - ECU"electronic control unit" , if necessary, complementing his affiliation yu to a particular group of blocks.
Please, ask for a complete listing of diagnostic codes , and if this is not possible, then ask the diagnostician, what function is missing or incorrectly performed ECU. Remember that failure to answer this question usually means poor quality. the diagnostics carried out and the corresponding level of knowledge of this"masters". Correct identification of a malfunction at a preliminary stage of diagnostics, as a rule, several times shortens our time for her final search and elimination and the money you spend for repairs.
Below we will try to list O main reasonscontributing malfunctions V ECU electronic control units ECU :
1. Unskilled intervention during car repairs.
2. "Lighting up" from a car with a running engine or from charger.
3. Swapped terminals + and
-
when connecting the battery.
4. Removing the battery terminals with the engine running.
5. Consequences exposure to time and harmful environment (oxidation of contacts in the block and the unsuitability of the tracks - in most cases it concerns blocks installed in the space of the engine compartment).
7. Ingress of water or other liquids into the inside of the ECU/PCM housing.
8. Malfunctions of the output circuits of the ignition system: coils, wires, distributor, candles. As a result - failure of components in the ECU.
