From the article you will learn what the main symptom of a sensor malfunction is. mass flow air. But before even visual diagnostics, you need to talk a little about what this device is, what its operating principle is, but the most important thing is to pay attention to maintenance and repair.

A mass air flow sensor is required for proper operation electronic control unit. Such systems are used only in injection engines. In other words, this is the majority domestic cars, which were released after 2000.

Basic information about the mass air flow sensor

It is called MAF for short. It is with its help that all air that enters the throttle valve for mixture formation is measured. It sends its signal directly to the electronic control unit. This mass air flow sensor (signs of malfunction, Priora or another model are the same) is mounted directly next to the air filter. Or more precisely, between it and the throttle assembly. The design of this device is so “delicate” that it is necessary to measure only thoroughly purified air.

And now a little about how this sensor functions. Engine internal combustion performs cycles in such a way that during one working stroke it becomes necessary to supply gasoline and air to the combustion chamber of each cylinder in a strict proportion - 1 to 14. If this proportion changes, there will be a significant loss of internal combustion engine power or a significant excess consumption of gasoline. Only if you adhere to this proportion will the engine function in ideal mode.

Sensor functions

And it is with the help of the mass air flow sensor that all the air that enters the fuel rail is measured. It first calculates the total amount of air, then this information is digitally sent to the electronic control unit. The latter, based on these data, calculates the amount of gasoline that must be supplied for proper mixture formation. And it does this in the right proportion. At the same time, the mass air flow sensor responds to changes in engine operating mode literally instantly. And a sign of a malfunctioning mass air flow sensor is a longer response to pressing the accelerator pedal.

For example, you start pressing the accelerator pedal harder. At this moment, the flow of air into the fuel rail increases. The mass air flow sensor notices this change and sends a command to the electronic control unit. The latter, analyzing incoming data by comparing it with the fuel map, selects a normal amount of gasoline. Another case is if you are moving uniformly, that is, without acceleration or braking. Then very little air is consumed. Consequently, gasoline will also be supplied in small quantities.

Processes during engine operation

And now a little more about how all these processes occur in an internal combustion engine. Elementary physics largely influences the work here. For example, when you press the accelerator pedal, the valve in the throttle assembly sharply opens. The more it opens, the more air begins to be sucked into the fuel supply system.

Consequently, when you press the gas pedal, the load increases, and when you release it, the load decreases. We can say that the DMRV monitors these changes. It is worth noting that the main symptom of a malfunction of the mass air flow sensor is a decrease in the dynamic properties of the car.

Design Features

This is one of the most expensive sensors in the internal combustion engine control system. The reason for this is that it contains an expensive metal, namely platinum. The basis of the sensor is a plastic tube of a strictly defined diameter. It is located between the filter and the throttle assembly. Inside the case there is a thin wire made of platinum. Its diameter is about 70 micrometers.

Of course, it is very difficult to measure the air passing through. In an internal combustion engine control system, air flow measurement is based on temperature measurement. The platinum wire is subjected to sudden heating. By how much its temperature drops in comparison with the set one, the amount of air passing through the sensor body is determined. Pay attention to the sign of a bad mass air flow sensor to know if it is OK.

Device maintenance

During operation of an engine with an electronic control system, the sensor still becomes dirty. To clean it, there is a special algorithm embedded in the control system. It allows you to heat a platinum wire in literally one second to a temperature of about a thousand degrees. If there was any dirt on the surface of this wire, it immediately burns without a trace. This is how to clean the mass air flow sensor. The signs of a malfunction, whether it is a Kalina or any other car, will be the same.

This procedure is performed every time you turn off the engine. The mass air flow sensor is very simple in design, and its operational reliability is high. However, it is not recommended to repair this unit yourself. If a breakdown occurs, then the best option You will turn to competent diagnosticians and mechanics.

Disadvantages of the node

Please note that if the sensor fails, it is most effective to replace it with a new one. It cannot be repaired, which is its main drawback, since the price of a new one is sometimes more than two thousand rubles. But there is another minor drawback, which lies in the principle of operation. Any mass air flow sensor has this drawback. Signs of a malfunction (diesel or gasoline in the power system) are discussed in the article.

It allows you to measure the volume of air that entered the throttle assembly. But for engine operation it is important to know not the volume, but the mass. Of course, to perform the conversion you will also need to know the air density. It is for this purpose that a measuring device is installed in the air intake, in close proximity to the sensor, which measures the temperature.

How to increase service life

Try to change the air filter on time, since the mass air flow sensor will not be able to work for a long time if dirty air passes through it. The thread and the entire internal surface can be washed using special sprays for carburetors. Just try to do everything carefully and avoid touching the spirals. Otherwise, you will end up with an expensive replacement of the air flow sensor. In recent years, other designs are often used instead of such a sensor. This type of mass air flow sensor is used on some foreign cars. Symptoms of a Nissan malfunction are similar to those that occur on “tens” or “Prior”.

A pressure sensor is often installed to monitor the flow of air into the combustion chambers. To increase the service life of the mass air flow sensor, it is necessary to promptly replace the air filter, and also pay attention to the cylinder-piston group. In particular, excessive wear on the piston rings will cause the platinum wire to become coated with oil deposits. This will gradually lead to damage to the sensor.

Major breakdowns

You should know how to identify a faulty mass air flow sensor. The internal combustion engine constantly changes its operating mode. Depending on the speed and load, a different air-fuel mixture is required. To mix it properly, you need a mass air flow sensor. It is also called a flow meter.

As you already know, it allows you to determine and adjust the mass of air that enters the fuel rail of the injection system. If your mass air flow sensor is working in ideal mode, then this is a guarantee that the engine will function normally. Please note that such a device cannot be repaired, even if you have many tools and accessories.

Symptoms of malfunctions

And now a little about what symptoms occur when the sensor breaks down. Often, when this element fails, the engine begins to idle intermittently, its speed constantly fluctuating. When accelerating, the car begins to “think” for a long time, there is no dynamics at all. Often the crankshaft speed also decreases or increases at idle. And if you are lucky enough to turn off the engine, then starting it turns out to be very difficult, and sometimes even impossible. This means that the mass air flow sensor needs to be replaced. “Priora”, the faults of which are scanned by the ECU, will definitely give an engine error.

Please note that it is not necessarily the sensor itself that has failed. It is not uncommon to observe small cracks or cuts in the corrugation that connects the sensor to the throttle valve. If you suddenly see that the Check Engine light starts to light on the dashboard, and the above symptoms are also present, then you can say that the flow sensor has become unusable. But you shouldn't rely on this alone. It is advisable to conduct a complete engine diagnostics. It is worth noting that the symptoms of a malfunction of the mass air flow sensor are very similar to those that appear when the TPS breaks down, for example.

The mass air flow sensor is necessary for efficient engine operation in different modes. The function of this device is to create a working mixture of air and gasoline vapor. The task of the VAZ 2114 air flow sensor is to measure two interrelated indicators:

1. Amount of air consumed;
2. Reaction time.

The accuracy of measuring the air consumption of the engine allows the controller to determine in what proportion it is necessary to mix air with fuel. If the sensor produces incorrect values, the resulting air-fuel mixture does not correspond to the current engine operating mode. This leads to a decrease in power, an increase in fuel consumption, and a deterioration in the dynamics and response of the car.
Controller response different manufacturers these parameters may differ.

For example, January-5.1, in case of slight overestimation or underestimation of values, determines the error of the mass air flow sensor based on the readings of the oxygen sensor, thus adjusting the duration of fuel injection. Increasing the sensor response time will cause the controller to not keep up, and at the time of acceleration you will notice “dips” of the engine. The same sensor error when using a more sensitive Bosch controller will lead to floating idle speed, although there will be no noticeable dips during acceleration.

A 1.5 liter VAZ 2114 engine with a working mass air flow sensor at 850-950 rpm consumes from 10±0.5 kg of air per hour of operation, and at 2000 rpm - from 19 kg to 21 kg. If the amount of air consumed at the same speed decreases, the dynamics of the car also decreases, but fuel is saved. Conversely, increased air consumption leads to increased dynamics and higher fuel consumption. In this case, it may be difficult to start the engine in cold weather. If the sensor readings deviate from the real ones by 2-4 kg, the engine will begin to become very capricious and “dull”. Disabling the sensor will force the motor to continue operating in emergency mode.

Causes of malfunction

The reason why the VAZ 2114 air flow sensor breaks down, characteristic of most domestic cars, is hidden in ventilation system crankcase It has two circuits that ensure operation when the throttle valve is open or closed. If the throttle is buried, crankcase gases are discharged along the line (d=1.5 mm) into the space available behind it. A certain percentage of these gases accumulates in the idle line, where it comes into contact with the film-coated MAF resistor. It is also sensitive to fluctuations in the gas mixture in the intake system. The resin settles on the surface of the resistor, and the sensor begins to “lie.” Because of this, the idle air control sticks, and it begins to jam when starting the engine.

Signs of malfunction

A non-working VAZ 2114 mass air flow sensor leads to the appearance of a number of symptoms in the behavior of the injection engine. The malfunction appears gradually, starting with an increase in fuel consumption and floating speed, ultimately destabilizing engine operation.

From personal experience using a front-wheel drive car as an example, I can say that I encountered the following problem: first the injector icon came on, then the speed began to fluctuate greatly and fuel consumption almost doubled.

You can calculate a non-working VAZ 2114 air sensor using the following criteria:

• failures when idling and under load;
• The internal combustion engine stalls when trying to change gear;
• decreased dynamics, the car accelerates slowly;
• fuel consumption increased;
• engine power has dropped;
• hard to start when hot;
• The Check Engine light appears.

If the mass air flow sensor is already dead, the Check Engine light may not come on. Then the malfunction can be determined by the error generated by the on-board computer. Diagnostics of the MAF signal level will also help. Low level may indicate the following:

• There is no MAF connection;
• malfunction in the sensor connection circuit (break);
• the ground in the connection circuit is broken or oxidized;
• the signal wires are broken or incorrectly connected, perhaps they are short-circuited;
• engine control unit malfunction;
• DMRV does not work.

If you notice the above signs, do not rush to buy a new sensor. It is by no means the cheapest and will cost 1500-4000 rubles. First of all, make sure that this is the reason. You can check and clean the old one at a service center or yourself if you have the necessary equipment.

Checking the mass air flow sensor

Before you start experimenting, take the time to read the manual service. It describes in detail what a mass air flow sensor on a VAZ 2114 is and how to replace it.

We are looking for a sensor. Open the hood and find the air filter pipe. The mass air flow sensor is located on it, which determines the flow of air passing through the filter. I will give several options on how to check the mass air flow sensor yourself.

• Disable the sensor. Disconnect the block with wires from the connector by pressing the latch located below. Start the engine (1500 rpm or more). The controller understands the shutdown of the mass air flow sensor as an emergency condition and prepares the fuel-air mixture based on the position of the throttle valve. Try driving a short distance. If the car accelerates noticeably faster, this indicates a non-working mass air flow sensor. I would like to note that in the disabled state for ECUs Y7.2 and M7.9.7. RPM doesn't increase!
• Replacing the controller firmware. The original ECU firmware could have been replaced with an alternative one. In such a situation, we do not know which algorithm is prescribed in the case of operation in the mode discussed in the first paragraph. The throttle valve has a stop under which you need to place a thin plate (about 1 mm) to raise the speed. Then you need to disconnect the chip with the sensor. If the sensor is faulty, the engine should stall. If the engine is running, then the reason is due to the firmware features: the IAC steps are written incorrectly.
• Voltage measurement. Testing gives good results when working with Bosch sensors. You will need a multimeter. Select the DC voltage measurement mode and set the maximum value to 2 V.

The connection diagram for the VAZ 2114 looks like this:

1. yellow – incoming signal;
2. gray with white – power output;
3. green – grounding;
4. pink with black – output to the main relay.

The colors may be different, but the sequence of connectors is the same.

Next, you need to turn on the ignition with the engine off. Connect the red (positive) probe of the tester to the yellow output, and the black (negative) probe to the green. Multimeter probes are inserted along the specified wires directly through the rubber seals of the connectors without damaging the insulation. For prevention, I recommend moistening the probes with WD-40. Intermediates or needles are not recommended due to the additional error they introduce. Measure the voltage. Compare the result with the table:

Just now installed sensor gives an output voltage of 0.996–1.01 V. It increases over time. A higher value means a higher percentage of wear.

Voltage data from the sensors is recorded by the on-board computer and can be viewed by selecting the appropriate group of parameters.

• Inspection and cleaning. Phillips screwdriver loosen the clamp holding the air intake pipe. We remove the corrugation and check whether there are traces of oil and/or condensation inside it, as well as on the inner surface of the sensor. Normally they shouldn't be there. The sensing element of the mass flow sensor often breaks due to dirt getting on it. This can easily be avoided by regularly replacing the air filter. Reasons for oil getting into the air flow sensor:

1. the permissible oil level in the crankcase has been exceeded
2. The oil separator of the ventilation system is clogged

The sensor is attached to the pipe with two screws. We unscrew them with an open-end wrench (x10) and remove the sensor itself. There is an entrance at the front, which must be protected from the leakage of untreated air with an o-ring rubber seal. If it is missing or remains in the filter housing, dust clogs the sensor input grid. It needs to be cleaned, the seal installed, the leaks checked and the sensor put back in.

• Comparison with a working sensor. On personal experience I was convinced that the most accurate test is to install a known working sensor and compare the behavior of the engine with the “native” one.

In addition to the options considered for how to check the mass air flow sensor yourself, you can also contact a service center that has special equipment and carry out 100% diagnostics, for example, using the method of evaluating an oscillogram.

Mass air flow sensor or maf sensor - what is it? The correct name of the sensor is Mass Airflow sensor; in our country it is often called a flow meter. Its function is to measure the volume of air entering the engine per unit of time.

Principle of operation

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The sensor consists of platinum threads (which is why it is not cheap), through which electricity, heating them. One thread is the control thread, air passes through the second, cooling it. The sensor produces a pulse-frequency signal, the frequency of which is directly proportional to the amount of air passing through the sensor. The controller records changes in the current passing through the second, cooled filament and calculates the amount of air entering the engine. Depending on the frequency of the signals, the controller sets the duration of operation of the fuel injectors, adjusting the ratio of air and fuel in the fuel mixture. The readings of the mass air flow sensor are the main parameter by which the controller sets fuel consumption and ignition timing. The operation of the flow meter affects not only total consumption fuel, mixture quality, engine dynamics, but also, indirectly, on the engine life.

What happens if you turn off the mass air flow sensor?

Let's start with the fact that when the flow meter is turned off, the engine goes into mode emergency work. What could this lead to? Depending on the car model and, accordingly, the firmware, the engine will stop (as on Toyota), increase fuel consumption, or... nothing. Judging by numerous messages from auto forums, experimenters note increased agility after shutdown and the absence of failures in engine operation. No one has carried out careful measurements of changes in fuel consumption and engine life. Whether it is worth trying such manipulations on your car is up to the owner to decide.

Signs of malfunction

A malfunction of the mass air flow sensor can be indirectly judged by the following symptoms:

• The CHEK ENGINE lamp comes on;
• The car accelerates slowly (stumbles);
• Unstable engine operation at idle;
• The engine does not start well when hot;
• Increased fuel consumption;
• The engine stalls while driving when changing gears.

Dirty DMRV (side view)

The symptoms described above can be caused by other reasons, so it is better to accurately check the mass air flow sensor at a service station using specialized equipment. If you don’t have time, don’t want to, or don’t feel like spending money, you can check the performance of the mass air flow sensor yourself with high, but not 100% reliability.

Dirty DMRV (top view)

Diagnostics of mass air flow sensor

Difficulties in self-diagnosis of a flow meter are caused by the fact that it is a capricious device. Taking readings at the number of revolutions specified in the manual often does not give results. The readings are normal, but the sensor is faulty. Here are several ways to diagnose the performance of the sensor:

1. The easiest way is to replace the mass air flow sensor with a similar one and evaluate the result.
2. Check without replacement. Disconnect the flow meter. Unplug the sensor connector and start the engine. When the DMVR is disabled, the controller operates in emergency mode. The amount of fuel for the mixture is determined only by the throttle position. At the same time, the engine keeps speed above 1500 rpm. If during a test drive the car becomes “faster”, then most likely the sensor is faulty
3. Visual inspection of the mass air flow sensor. Remove the corrugated air intake tube. First, carefully inspect the corrugation. The sensor may be working properly, but the reason for its unstable operation is cracks in the corrugated hose. If the surface is intact, continue the inspection. The elements (platinum threads) and the inner surface of the corrugation must be dry, without traces of oil and dirt. The most likely cause of the malfunction is contamination of the flow meter elements.
4. Checking the mass air flow sensor with a multimeter. The method is applicable for Bosh mass air flow sensor with catalog numbers 0 280 218 004, 0 280 218 037, 0 280 218 116. We switch the tester to measure DC voltage, with a measurement limit of 2 Volts.

Location from closest to windshield in order 1. sensor signal input 2. mass flow sensor supply voltage output 3. grounding (ground). 4. output to the main relay. The color of the wires may vary, but the pin locations are always the same. Turn on the ignition without starting the engine. We connect the red probe of the multimeter through the rubber seals of the connector to the first contact (usually yellow wires), and the black probe to the third one for ground (usually the green wire). We look at the multimeter readings. A new sensor will typically read between 0.996 and 1.01 Volts. Over time, tension usually increases. A higher value corresponds to more wear on the sensor. 1.01…1.02 – sensor is working. 1.02…1.03 – the condition is not the best, but working 1.03…1.04 – the resource is at its limit. 1.04...1.05 - agony 1.05...and more - definitely, it's time to change.

All of the home diagnostic methods described above do not provide a 100% guarantee of the reliability of the result. A reliable diagnosis can only be made using special equipment.

Do-it-yourself prevention and repair of mass flow sensors

Timely replacement of the air filter and monitoring the condition of the piston rings and seals can extend the life of the mass air flow sensor. Their wear causes excessive saturation of crankcase gases with oil. An oil film getting on the sensitive elements of the sensor kills it. On a sensor that is still alive, lost readings can be restored by the “Max air flow sensor corrector” program. With its help, you can quickly change the mass air flow sensor calibrations in the firmware. The program is easy to find and download without problems on the Internet. The luftmassensensor reiniger MAF cleaner can help revive a non-working sensor.. To do this you need:

• Remove the sensor from the engine as described above.
• Spray the product thoroughly and generously onto the sensitive element.
• Wait until any remaining dirt has drained away.
• Dry the sensor well before installation. For prevention, the procedure can be repeated before each air filter replacement.

MAF Toyota 22204-22010

If cleaning does not produce results, the faulty sensor must be replaced. The cost of a mass air flow sensor starts from 2000 rubles, and for imported models it is usually significantly higher, for example the price of a Toyota 22204-22010 sensor is about 3000 rubles. If the sensor is expensive, do not rush to buy a new one. Often products of the same marking are installed on different brands of cars, but the price as spare parts is different. This story is often observed with Bosh mass air flow sensor. The company supplies the same sensors for VAZ and for many imported models. You need to disassemble the sensor, write down the markings of the most sensitive element, it is quite possible that it can be replaced with a VAZ one.

DBP instead of MAF

In imported cars, since the 2000s, a pressure detector (DBP) has been installed instead of a flow meter. The advantages of DBP are high performance, reliability and unpretentiousness. But installing instead of a mass air flow sensor is more for those who are interested in tuning than for ordinary car enthusiasts.

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The air flow sensor is necessary for the engine management system to organize proper operation. It allows you to track how much air has passed to the throttle valve from outside. The signal generated at its output is fed to the electronic control unit. The latter carries out processing and, according to the underlying algorithm, calculates the required amount of gasoline for proper injection operation. Failure of the sensor disrupts the functioning of all systems. The engine runs erratically because the electronic brain cannot understand how much fuel the engine requires.

Basic functions of the sensor

As stated above, it determines the exact amount of air consumed by the fuel system. Not pure gasoline enters the combustion chambers; it is mixed in a ramp with air; the ideal proportion is 1:14, respectively. When fed with such a mixture, the engine operates in normal mode and is capable of producing high performance. When the proportion changes, the engine loses power, and gasoline consumption also increases significantly.

Consequently, the VAZ-2110 air flow sensor, for example, allows you to determine the amount of air that has passed into the fuel rail. The joint operation of all measuring instruments, such as throttle position sensors, crankshaft and camshaft sensors, speed, pressure, allows the engine to normalize. By collecting all the information, it is possible to ensure uninterrupted operation of the motor under various loads.

The operation of the mass air flow sensor as an example

Imagine that you are driving a car. To increase speed, you need to press harder on the accelerator pedal. At this moment, many processes occur, and all characteristics change. If you open the throttle with the pedal, more gasoline flows. The more it goes into the combustion chambers, the more air is required to create an ideal air-fuel mixture.

To properly mix air with gasoline, a sensor is installed in the engine intake system. But for proper operation it is required that the air supplied is as clean as possible, without dust and other small particles. A filter is provided for this purpose. Another situation: you release the gas pedal, intending to reduce speed. If the same amount of air is supplied as for high speed, the engine will stall. The VAZ air flow sensor allows you to avoid this, if you already started giving an example on the “ten”.

Sensor device

The basis measuring instrument- This is a plastic tube through which air passes. It contains a thin platinum wire (its diameter is about 70 microns). When the engine is running, this wiring heats up. The temperature of the wire during operation fluctuates around one hundred degrees. There is nothing complicated, as it might seem, in the design. The wire warms up, and the change in its temperature shows how much air has passed through the tube.

All this is calculated according to the algorithm embedded in the central control unit. The design also has resistors, which are necessary to stabilize the operation and adjust the current values. It is against this parameter that measurements are made. It is worth noting that the air flow sensor, the price of which on average is about 2000 rubles, contains a precious metal - platinum. The central wire and mesh are made from it. There is nothing to replace platinum, so there is no hope that the price of the device will fall. And if a malfunction of the air flow sensor occurs, its resuscitation is almost impossible.

How the device works

Having dealt with the device, in which there is nothing complicated, but there is precious metal, you can begin to review the functioning process. So, when the ignition is turned on, the platinum wire begins to heat up. It is located clearly in the middle of the plastic tube and is the arm of the main bridge of resistors. In the circuit, the current strength is constantly kept at the same level, due to which the temperature is stable. You press on the gas pedal, the throttle valve opens and air is drawn into the fuel system. The flow cools the wire, and the resistance of the platinum drops.

The control system notices the temperature change and increases the voltage to heat the wire to the desired value. Only after the temperature has stabilized will the system come into equilibrium. At this moment, the resistance of the platinum wiring and its temperature will have an optimal ratio. It is worth noting that the current that flows through the measuring wire varies from 500 to 1200 μA. It also flows in the calibration resistor circuit, which sends a signal to the control unit. The latter, having received the data, calculates the required amount of gasoline according to the fuel map.

Carrying out maintenance

The sensor does not require any maintenance as such. Measures to clean the system are taken by the electronic control unit. And if the air flow sensor, the signs of malfunction of which will be discussed below, is broken, then a lot of dirt and dust will accumulate in it. The air entering the tube cannot be completely cleaned by any filter. Therefore, a method is provided by which all the dirt that accumulates on the platinum wire literally evaporates. There is a small peculiarity in the operating algorithm of the electronic control unit.

When you turn off the engine, a voltage is applied to the platinum wire that can heat it up to 1000 degrees. The heating occurs within a second, this time is enough to get rid of all the accumulated dirt on the surface of the wire. If you decide to restore the sensor yourself, you will need to thoroughly clean the wire and mesh. When carrying out work, it is forbidden to touch these objects, otherwise you will only have to change the entire device; it will not be able to work normally.

Disadvantages of the air flow sensor

Despite all the words said above about the simplicity of design and operation, the device has many disadvantages. The most important thing: it cannot be repaired. It’s unlikely that anyone will want to spend 2,000 rubles on a new one. It is, of course, possible to clean the sensor, but this should only be done if you have the appropriate qualifications and experience. And if the wire is damaged or even torn off, you should not even try to revive the sensor.

Among the disadvantages is that it does not measure air mass. It monitors the volume that has passed through it. This complicates the entire system, since it is necessary to know the air density to calculate the mass. For this purpose, a sensor is provided that measures temperature. Without measuring this parameter, it is impossible to calculate the mass. Modern designers have tried to move away from the classic MAF design and conducted tests with pressure sensors. As a result, the Nissan air flow sensor from the early 2000s began to measure air pressure rather than volume.

Signs of malfunction

The first sign that will immediately catch your eye is the illuminated CHECK ENGINE light on the instrument panel. Unfortunately, it talks about all engine breakdowns, so there are two options for determining an accurate diagnosis - visit a service station or monitor the condition of the engine in different operating modes. The second one turns out to be cheaper, but there is not much chance of determining which component in the engine is acting up. The symptoms of many breakdowns are the same. So, the engine can “triple” both due to malfunctions in the ignition system and when there is a breakdown in the fuel mechanism. Therefore, it is better to spend money, but send the car to a diagnostician who will tell you exactly which element has failed.

An increase or decrease in idle speed clearly indicates that there is a malfunction in the fuel supply system. In particular, such symptoms are also characteristic of defects in the air flow sensor. When accelerating, the car “thinks” for a long time, the speed is gained extremely slowly. The idle speed not only changes, but also becomes unstable. And this is only if the engine was able to start at all. Often it does not respond at all when the starter rotates. Here's how to test the air flow sensor by analyzing only external signs. But an accurate diagnosis can be made only after complete disassembly of the device.

Replace or repair?

When the sensor breaks down, the following question immediately arises. But you need to immediately decide whether there is a malfunction in the device itself? Breaks and defects of active elements are extremely rare, but contamination is a popular cause of failure. There is a violation of the integrity of the corrugated hose that connects the sensor and the throttle. The presence of cracks on it causes CHECK ENGINE to light up and the engine simply stops working.

Therefore, you need to make sure that the fault lies in the sensor. If contamination occurs, it can be removed with a special spray. These are sold in stores for cleaning the throttle body. Please note that wiping the inner surface with your fingers or a cloth is prohibited. Only contactless cleaning is allowed.

Conclusion

To avoid expensive repairs, because even the VAZ-2110 air flow sensor costs a decent amount - about 2,000 rubles depending on the manufacturer, carefully monitor the condition of your car. Timely replacement of the air filter is a guarantee of stable and trouble-free operation of the air flow sensor on any car. You also need to pay due attention to the condition of the piston group. If oil begins to be thrown into the throttle assembly, then destruction of the mass air flow sensor is inevitable.

The mass air flow sensor (MAF or flow meter) is important detail a car, the proper operation of which determines engine power and fuel consumption. You can find it under the hood of the car, where it is located between the air filter and the air pipe directed to the throttle valve. The task of the mass air flow sensor is to measure the amount of air passing into the cylinders and transmit this information to the electronic control unit, that is, to the “brains” of the machine. Based on the data from the mass air flow sensor, the control unit decides whether to increase or decrease the air supply to the combustible mixture.

If the mass air flow sensor fails, it is almost never repaired, but simply replaced with a new one. Its design is quite simple, and it consists of a housing in which a device for measuring air flow is placed - a hot-wire anemometer. It is enough to damage the diagnostic device during the process of dismantling the mass air flow sensor or cleaning it, and the entire sensor will need to be replaced. It can also fail if long term service, but you can verify its malfunction only after checking.

Symptoms of a malfunctioning mass air flow sensor

Before you start checking the mass air flow sensor, you need to understand from the primary symptoms that it is faulty. The following symptoms may indicate problems with the sensor:

The above symptoms indicate that air is not supplied to the combustible mixture in the volume required. Wherein this problem can be observed not only when the mass air flow sensor fails. In particular cases, the malfunction may be due to a lack of power supply to the sensor through the electrical wiring or when cracks appear in the connecting hoses.

How to check the mass air flow sensor for serviceability

There are several basic methods for checking the mass air flow sensor, which allow you to verify its malfunction.

Checking the mass air flow sensor in motion

The easiest way to diagnose a flow meter is to analyze the operation of the engine when the sensor is forcibly turned off. The check proceeds as follows:

Checking the mass air flow sensor with a multimeter

You can diagnose a problem with the sensor using a multimeter. To do this, you must first understand the design of the device and its “pinout,” that is, the wiring of the wires on the board. There are 4 wires coming out of the mass air flow sensor. Depending on the MAF model and manufacturer, their colors may vary, but in most cases they are as follows:

• Pink (or pink-black): wire to main relay;
• Green: wire to ground;
• Gray: wire to power;
• Yellow: signal input.

To check the mass air flow sensor, the multimeter must be set to constant voltage measurement mode and set the limit to 2 Volts. Next, you need to turn on the ignition, but do not start the engine. Once this is done, connect the multimeter's red lead to the sensor's signal input (yellow wire) and the black lead to ground (green wire). This can be done without “exposing” the wires by inserting the probes of the diagnostic device through the rubber seal of the connector.

Based on the measurement results, conclusions can be drawn about the state of the sensor:

Some modern on-board computers allow you to view the voltage on the mass air flow sensor. In such situations, you can do without a multimeter.

Visual inspection of the mass air flow sensor

Experienced motorists can determine the malfunction of the mass air flow sensor by its appearance. The first step is to remove the mass air flow sensor, and then inspect it carefully. Signs of a malfunction are liquid getting into the air pipe and the mass air flow sensor (or the presence of mechanical damage).

Most often, liquid may end up in the sensor for the following reasons:

• Increased oil level in the crankcase. In such a situation, oil enters the sensor;
• Clogged oil sump of the crankcase ventilation system;
• Untimely replacement of the air filter, due to which dirt gets onto the MAF hot air anemometer.

The easiest and most reliable way to diagnose problems with the mass air flow sensor is to replace it with a working device. For example, you can remove a suitable working sensor from another car, install it and make sure that engine operation has stabilized. In such a situation, you can immediately go buy a new sensor without diagnosing it with a multimeter or other methods.