Toyota allex dmrv sensor what does it affect. Visual inspection of the DMRV

The engine of a modern car is capable of developing maximum power and torque only with correct and precise mixture formation. Therefore, an important role in ensuring the operation of the power unit is played by an air mass meter - a small unit that regulates the amount of air supplied to the cylinders.

There are several types of air flow meter with different methods measurement of air volume. Node over old design uses a so-called pitot tube and is called a vane flow meter. In it, a special plate deviates under the influence of air movement. A potentiometer is mounted on the axis of the plate, which changes its resistance depending on its deviation.

In more advanced flow meters, a hot-wire anemometer is used. In this design, a thin platinum heat exchange element is provided. The more air passes through a given node, the more electricity is needed to maintain the temperature difference between the element and the air. The diameter of the platinum element is 0.07 mm. Note that over time, deposits appear on it, changing the characteristics of the work. Therefore, to combat this phenomenon, the element is able to self-clean, heating up after the motor stops for a short time up to a temperature of 1000-1100 degrees.

The latest technology is hot-wire anemometric flowmeters, which have a film air meter. The heating and measuring elements of the unit are silicon crystals with thin platinum layers deposited on them. The vykhrevy type is less common. In these parts, the frequency of vortexes that appear behind the protrusion in the inlet wall is measured. Please note that many modern foreign-made cars lack the described assembly. It is replaced by an absolute pressure sensor in the intake manifold.

Like any other component, the air mass meter is subject to wear and can break. The following signs testify to its failure: intermittent idling; slow set of speed and the appearance of dips; increase or decrease in idle speed; increase in fuel consumption. Also, the engine of the car may not start at all. The spade type usually fails due to wear on the conductive surfaces of the potentiometer or oil getting on the working surfaces.

In the first case, the signal from the air flow meter is transmitted to the computer intermittently and in a distorted form. The second factor leads to damper jamming. Hot-wire view may not work due to broken power wires, as well as after poor maintenance. The insides of this unit are very sensitive, so you should not try to clean them or even wipe them from dirt. You can only blow it out with a compressor. This type of air mass meter is non-repairable. Therefore, with symptoms of a breakdown, you can only check the contacts.

More accurate information about the presence and nature of the malfunction will help the diagnostic system, which is available on almost all modern cars. The disadvantage of such diagnostics is that in order to decipher the malfunction behind the Check Engine signal, you need to visit a service station or purchase an on-board computer. radical way checking the performance of the air flow meter - replacing it with a new one. If such a measure does not bring results, then it is necessary to look for a breakdown elsewhere.

If the air mass meter is found to be inoperable, it is recommended to replace it with a new unit. Only blade-type parts can be restored. In them, you can clean the plate of dirt using carburetor cleaning fluid. The potentiometer is "returned" to life by moving the contact track or bending the current collector plates.

In both cases, the goal of the operation is to move the "route" of the movement of the tip to the undamaged part of the track. Some experts "repair" the air mass meter by turning off its power. This should not be done, as this inevitably leads to an increase in gas mileage.

The stability and efficiency of the engine are largely dependent on the serviceability and condition of the ECU sensors. One such device is a sensor. mass flow air. The accuracy of its readings determines the quality of the prepared combustible mixture, and the resulting malfunction will immediately affect the operation of the power unit. To check the performance of the device, there are several simple ways, allowing to assess its condition, and in the event of a malfunction, make a decision to repair or replace the device.

Purpose and principle of operation of the DMRV

DMRV scheme

DMRV is located after air filter in order to determine the volume of air passing through the filter into the engine cylinders. The first models of the device calculated the flow rate by the magnitude of the deflection of the petal relative to the air pressure. Modern versions of the device work on the basis of a sensor having a platinum or silicon thermoelement with a platinum coating.

The principle of operation of the platinum element is the rate of its cooling by air flow. To adjust the temperature difference between it and the air is supplied electricity, the value of which is adjustable. More intense blowing causes a higher voltage to be applied. To reduce the degree of contamination, a self-cleaning system is connected to the element.

Platinum has a high thermal conductivity, due to which the volume of air passing through the duct is calculated from the cooling rate of the heated temperature sensor. The air, even after passing the filter, is not completely cleaned of soot particles, dust and resins present in the atmosphere. To reduce deposits, the platinum element burns out organic plaque when the ignition is turned on, heating up to a white heat with an electric current.

Symptoms of a malfunctioning DMRV

Blockage of the mesh in front of the DMRV

A malfunctioning DMRV is manifested in the following symptoms:

1. "Check Engine" error signaling.
2. Deterioration of the acceleration dynamics of the car.
3. Increased fuel consumption.
4. Loss of engine power.
5. Poor engine start when hot.

Air mass sensor distortion causes the engine to run lean with loss of power. Long term operation power unit in this mode leads to the melting of the catalyst in exhaust manifold and burning exhaust valves. The reason for checking the sensor should be the following signs:

1. Superheated atmosphere under the hood due to a hot exhaust manifold.
2. Decreased throttle response and engine thrust along with an increase of 10-15% in gasoline consumption.
3. Dips during launch or acceleration change normal work. In this case, the candles must be replaced with known working ones.

Possible causes of a malfunction of the DMRV

Check Engine light on

The main reason for the failure of the air sensor is the contamination of the platinum element by debris particles that have passed through the air filter. The remaining breakdowns are associated with the problem of the absence or violation of the contacts of the wires suitable for the device. The problem may be their breakage, oxidation, cracks in the corrugated hose leading from the flow meter to the throttle module. A breakdown in the DMRV circuit will be reported by the CHECK ENGINE lamp, but its cause can only be accurately determined at a specialized service station.

Checking the DMRV

Troubleshooting the MAF can be done in the following ways:

Removing the DMRV together with the body

1. visual inspection sensor. The device is removed and inspected inner surface and air duct. There must be no traces of oil or condensation, and the surface must remain dry and clean. If contamination is present, the device must be cleaned and the cause of the contamination eliminated, after which the sensor should work correctly.

DMRV with a disabled chip

2. Disconnect the connector connecting the sensor and the control unit, after which the engine will go into emergency operation, in which the composition of the combustible mixture is calculated not by the amount of air consumed, but by the throttle position. After switching off the sensor, the engine speed rises to 1500 rpm. Next, you should drive by car. If its driving dynamics has improved, then the probability of a malfunction of the DMRV is high.

3. Replacing the standard sensor with a known good one, after which the operation of the engine is evaluated. If it behaves noticeably better, then the device needs to be cleaned or replaced.

Checking the MAF with a multimeter

4. Checking the sensor with a multimeter. To do this, measure the input voltage from the device by setting the meter to a constant current and a scale of 2 V. The probes touch the green and yellow wires connector, which from the side of the windshield will be the first and third in a row. In different brands of cars, the color of the wiring may be different, but the arrangement is the same.

After the ignition is on (do not start the engine), measurements are taken. The new sensor produces a voltage of 0.996-1.01 V. If its condition worsens, the indicator increases, and the value of 1.03-1.04 indicates an imminent failure of the DMRV. At a voltage above 1.5 V, the device is replaced with a new one.

It is possible that the incorrect operation of the DMRV is associated with the installation of a modified version of the firmware in the ECU. This is checked by installing a plate, 1 mm thick, under the damper stop. When the engine speed increases, disconnect the sensor terminal. If the engine continues to run, the ECU is to blame for the malfunction, which does not respond to emergency operation without a DMRV.

DMRV repair

Filmed DMRV

Any contaminant reduces the heat dissipation of the platinum temperature sensor and makes it read incorrectly. It is pointless to check the accuracy of work in this state, and many service station specialists change it to a new one without bothering to clean and check the device. But in most cases, the procedure for removing dirt from the platinum surface of the original sensor makes sense, since the cost of a new device is quite high.

Liquid LIQUI MOLY

For this, a liquid in an aerosol can is used, which is used to clean carburetors. Before starting the procedure, the fastening clamps are loosened, and the sensor is removed from the duct pipe. The platinum substrate is carefully removed by unscrewing a couple of screws with an asterisk. Cermet or thin wire is treated with a tool without touching the part with your hands. Fluid consumption and the number of treatments is chosen at your own discretion.

An alternative cleaning mixture can be a solution of alcohol and acetone, which is blown together with a stream of purified compressed air. If black spots or severe erosion of the working part are found after disassembling the sensor, it is soaked for several hours in acetone by applying an impregnated swab to the surface for several hours. After cleaning and assembly, the device is checked with a multimeter. Often the performance of the DMRV is restored, albeit at a minimal level.

If the mass air flow sensor fails, the operation of the injection system will be disrupted, and hence the functioning of the engine of the machine as a whole. If there are signs of a malfunction of the DMRV, the easiest way to diagnose is to install a known working device instead of the controller.

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What is DMRV and its purpose

In a car, this controller is a device used to estimate the amount of air that enters the engine. The sensor belongs to the class of regulators of the electronic control mechanism of the power unit. The first thing that the DMRV affects is the operation of the injection system. The device is designed to determine and regulate air flow, which enters the engine cylinders in order to form a combustible mixture. The controller in a car can be used in conjunction with air pressure and temperature level sensors, which are used to change its readings.

Where is he located?

The regulator can be seen under the hood. Regardless of the model vehicle, the sensor is installed in the intake tract, after the air filter device. The controller is fixed on the air duct.

The channel "In Sandro's Garage" spoke about diagnostics, as well as the location of flow meters in VAZ cars.

Principle of operation

The principle of operation of the DMRV can be based on counting Kraman vortices or shifting the potentiometer slider by means of a blade mounted on the air supply stream.

The first option is considered more reliable, since it is not equipped with moving structural elements. In this case, the device counts the Kraman vortices that appear in the laminar air flow. On the way of the latter, special obstacles with sharp edges are used as resistance. An air flow breaks off from them, which linearly depends on its speed. This type of controller only works if there is turbulence in the air.

The StarsAuto channel spoke about design features, as well as the principle of operation of automotive flow meters.

If the sensor is equipped with a measuring potentiometer, then it functions according to the slider displacement principle. Its working blade is equipped with a spring and is installed in the flow of air consumed by the motor. If it increases, there is a proportional displacement of the blade. The flow has a pulsating character, respectively, to reduce the effect of pulsations, the controller blade is connected to a damper. A potentiometer slider is also associated with it, which, when the sensor is operating, is shifted to a level proportional to the volume of air flow.

This structural element is carried out on ceramic surface where the resistor elements of the voltage divider are installed. Their conclusions are arranged in a row and covered with a special resistive layer. The slider of the device is pressed against the contact component. Due to this, the voltage level on it corresponds to the value at the point of contact with the resistive layer. If the blade changes its position, the elements move, which leads to abrasion of the slider.

DMRV design

Structurally, the mass air flow sensor includes six elements:

• working board of the device;
• plastic case;
• radiator element;
• sensitive component in the form of a wire or a nickel network;
• a pipe through which the air flow passes;
• meshes at the outlet and inlet of the device.

The sensitive component must be supplied with current, otherwise it will not be able to heat up. During operation of the device, the average temperature of the thread should be 75-100 degrees.

Photo gallery "Design DMRV"

Filament device with circuit board inside Film flow meter for cars

The most popular malfunctions of the DMRV

The main signs of a malfunction of the DMRV:

1. Flow meter malfunctions can be reported by the Check Engine indicator, which appears on dashboard inside the car.
2. Depending on the type of device and machine, an icon may appear on the control panel, indicating a low signal level of the MAF.
3. The power unit began to work intermittently. When the sensor is disconnected, the car stalls or the engine speed starts to jump up or down. The power of the internal combustion engine is reduced, the car hardly takes acceleration, especially moving uphill.
4. Increased fuel consumption.
5. When changing gears on the gearbox, the engine randomly stops.

A faulty sensor can be identified by the integrity of the case. The presence of damage on it, as well as on the corrugated line, may indicate a malfunction in the controller. This is a pipe that connects the regulator to the throttle valve. If the engine randomly stalls during operation, this may indicate a malfunction in the power line.

If the air quantity and distribution control device is faulty, then the symptoms of a breakdown may be similar to errors in the operation of the air filter.

Reasons why the device fails:

• the sensor is not connected to the power supply of the machine;
• breakage or damage to the power circuit;
• malfunctions in the operation of the controller may result in malfunctions in the operation of the engine control unit;
• incorrect connection of signal cables or their breakage;
• oxidation or damage to contact elements.

Diagnosis of DMRV

If there is no similar sensor, then there are other ways to check the operability of the flowmeter:

• visual diagnostics;
• checking while driving;
• determination of firmware compliance;
• tester diagnostics.

visual inspection

Before checking the device with this method, it must be dismantled from seat. To do this, the pipes are disconnected from the air filter element housing. Inside the controller must be dry, traces of motor fluid and condensate are not allowed. Often the device breaks down due to non-observance of the air filter change intervals, as a result of which dirt remains on the sensitive component. This causes the controller to give incorrect readings.

If there are traces of motor fluid on the internal cavity of the controller, this indicates high level lubrication pressure in the power unit. The reason may be clogging of the crankcase ventilation. When checking, make sure that the sealing element is located in the right place where the corrugation is installed. This part could be stuck in the air filter housing. With this problem, air is sucked into the engine, which gets inside with dust and contaminates the regulator.

Diagnostics on the move

It is necessary to disconnect the plug with the power circuit from the sensor and start the engine, and then disconnect the block. The Check Engine indicator will appear on the dashboard. The minimum engine speed should increase to 1500 per minute. If the engine began to work more stably after turning off the device, this indicates a malfunction. The sensor needs to be replaced.

User Igor Belov spoke about several methods for diagnosing the flow meter, including checking while driving.

Compliance of the DMRV with the ECU firmware

To check the compliance of the firmware, you need to take a plate 1 mm thick and bring it under the damper stop, this will lead to a change in engine speed. Then the block with wires is disconnected from the controller. If the engine of the machine did not stop, then the reason is the firmware of the microprocessor module, the regulator idling without a flow meter in emergency mode.

Checking the MAF with a multimeter

For diagnostics, the ignition is activated, but power unit no need to run. The contact of the red probe on the tester must be touched to the first cable (yellow), and the black one goes to ground (green contact). For connection, the use of sharp objects is not recommended, as this will lead to an error in the readings. This diagnostic method will determine the voltage level between the conductors.

The status of the sensor will allow you to find out the readings:

• from 0.99 to 1.01 V - parameters of the new controller;
• 1.01 - 1.02 V - the regulator is in excellent condition, no need to change;
• 1.02 - 1.03 V - generally satisfactory condition of the device;
• 1.03 - 1.04 V - the life of the controller is almost exhausted, replacement will soon be required;
• 1.04 - 1.05 V - unsatisfactory condition of the sensor, it's time to change the device.

Tester diagnostics may not be performed on all types of flowmeters. The pre-diagnostic mode of the multimeter must be set to measure the DC current and set the maximum parameter to 2 V. Four cables are connected to the controller, each of which is indicated by a certain color.

Starting from the nearest conductor to the windshield:

• the yellow contact is for flowmeter pulse input;
• white or gray cable is used as the output channel of the supply voltage;
• green contact is ground or ground;
• a black cable equipped with a pink stripe is responsible for the output to the main relay.

The colors of the contacts on the DMRV may be different, but the location of the wires is always identical.

The Simple Opinion channel talked about the flow meter diagnostics using a tester.

What to do with a low signal level of the MAF?

With such a problem, diagnostics are performed:

• the presence or absence of supply voltage, as well as the reliability of connecting the device to ground;
• the resistance level between the contact element 5 (in the diagram) of the connector and ground, this figure should be from 4 to 6 kOhm.

The problem may be:

• poor quality contact;
• wrong route of the harness with wiring;
• wear or damage to the cable core or insulating layer;
• poor connection of the device to ground;
• connecting more powerful energy consumers to the block.

Device diagnostics includes the following steps:

1. The quality of the contact between terminals 7 and 12 on the connector of the injection system, as well as the sensor is checked. A visual check is made of the condition of the block for proper connection. The problem may be damage to the locks or the use of damaged contact elements. Maybe poor quality connecting the conductor to the block.
2. You need to make sure that the harness route is not broken. Problems can arise if the cable bundle is laid next to high voltage wires.
3. The integrity of the harness is checked, no damage is allowed on it. If the element is visually intact, you should try to move it and at the same time monitor the readings of the diagnostic equipment.
4. The clogging of the air filter device is also checked. If required, it is replaced.

If you have a tester, you can check the health of the mass air flow sensor as follows:

1. The key in the lock scrolls to turn off the ignition. It is necessary to disconnect the connector with wires from the controller.
2. Then the ignition is turned on, but the power unit does not start.
3. Using the tester, the voltage level between the contact elements on the connector is diagnosed. Between outputs 2 and 3, this value should be above 10 volts, between 3 and 4 - 5 V, and between ground and the third contact - 0 V. If the obtained indicators are different, you need to eliminate breaks in the line and get rid of a short to ground.
4. The car's ignition is then turned off. Using a multimeter, the resistance level between the fifth pin and ground on the block is diagnosed.

Scheme of connecting the flowmeter to the microprocessor

If the value obtained is about 4.6 kΩ, then the regulator itself is faulty. The problem may lie in its poor-quality connection. At a resistance level of 0 ohms, the problem is a fourth contact shorted to ground or a sensor malfunction. If the value obtained was more than 100 kOhm, this indicates a break in the 4G wire or a breakdown in the regulator.

What to do with a high level of the DMRV signal?

With this problem, it is also necessary to check the presence of voltage on the power circuit and the quality of the connection of the sensor to ground. The parameter is also diagnosed on the fifth contact of the connector.

The check is done like this:

1. The ignition is turned off. Disconnect the connector with wires from the device.
2. The ignition turns on, the engine does not start.
3. Using a multimeter, the voltage on the block is diagnosed. The readings obtained should be the same as when the sensor signal was low.
4. Then the resistance is measured, the tester must first be set to the appropriate mode. The measurement is carried out between the fifth contact element and earth. If the value obtained is 0 V, then the regulator is defective and must be replaced. Other parameters will indicate the short circuit of the 4G conductor to the power source.

How to clean the sensor yourself?

By cleaning and flushing the air flow controller, you can restore its operation.

In particular, you will have to work with the sensitive element of the sensor - this part always gets dirty during the operation of the flowmeter.

Choice of purifier

To complete the task, you must purchase a cleaning agent:

1. Liquid Moly. The mass air flow sensor cleaner of this brand is not cheap. But its use allows you to effectively remove contaminants and restore the operation of the device. The use of Liquid Moli cleaning agents can be carried out on DMRVs running on gasoline or diesel internal combustion engines.
2. Technical or medical alcohol. This option is one of the oldest and most effective. Chemical properties alcohol allow you to qualitatively remove dirt from the sensitive part of the sensor.
3. Carburetor engine cleaner. One of the most affordable and effective ways restore the controller.
4. Means Liquid key. It is allowed to be used not only on the DMRV, but also for the purpose of cleaning other components and mechanisms.
5. WD-40. Allows you to remove not only dirt, but also traces of rust.

Step-by-step instruction

Do-it-yourself mass air flow sensor repair is carried out as follows:

1. Before removing the sensor, turn off the ignition and disconnect the terminal from the battery. In the engine compartment, the connector is dismantled from the flow meter.
2. A pipe is connected to the device, it is also loosened and disconnected. Using a wrench, a bolt is unscrewed that fixes the mechanism on the air filter, in particular, on its housing.
3. The device is removed from the corrugation. Depending on the car model, this may require different instruments, including asterisk keys. The self-tapping screws fixing the device are unscrewed, and then the flow meter is removed from the landing site.
4. If there are traces of oil on the device, they must be removed. To clean up, use one of the above tools.
5. The sensors themselves on the flow meter are usually made in the form of a wire located on a grid. Using a cleaner, it is necessary to carefully process the sensitive component. Film cannot be damaged. When the place of contamination is cleaned, it is necessary to wait about 10 minutes for the product to work.
6. If there is too much dirt on the device, it is advisable to repeat the cleaning procedure several times. To ensure rapid evaporation of the product, you can use a compressor or pump. But too high pressure can lead to the destruction of the sensitive element of the flowmeter.

Photo gallery

Removing the sensor and replacing it

The service life of the device is affected by the purity of the air flow that passes through it. Therefore, when using a flowmeter, it is necessary to prevent the formation of deposits on it. working surface. To do this, it is recommended to periodically check the functioning of the air filter device. If necessary, the sensor must be changed regularly. If the car is operated in a large and polluted city, then the part must be replaced more often than indicated in the car maintenance regulations.

A modern injection car is filled with big amount electronic sensors, which collect information for the controller and based on this data, a decision is made on the amount of fuel injected. If one of the sensors malfunctions, the computer will stop receiving information and then the engine switches to emergency mode, in which fuel consumption increases. No exception is the mass air flow sensor, which plays in this complex process very important role. Therefore, you need to know what it is, as well as what signs of a DMRV malfunction indicate that it is time to replace it.

The air sensor, as it is commonly called, is a small electronic device, designed to estimate the amount of air that enters the cylinders throughout the operation of the engine. As you know, when opening and closing the throttle, the load on the motor changes, respectively, it is necessary to correctly apply right amount fuel and air so that the engine runs most efficiently and economically.

The mass air flow sensor consists of plastic case, and inside it is a wire made of platinum. During the operation of the engine, the wire is under a small voltage, and accordingly, it heats up. With an increase in air flow, the wire cools, which means its resistance changes. Accordingly, the circuit tension changes, which the computer immediately "learns" and gives a command to increase or decrease the fuel supply.

If the mass air flow sensor is defective, this ratio will not be created correctly. The fact is that the computer will receive incorrect information, which means that the amount of fuel and air entering the cylinders will be incorrect, which will lead to engine malfunction or increased fuel consumption. Therefore, it is very important to be able to determine the health of the DMRV and change it in time in case of a breakdown.

Symptoms of a malfunctioning DMRV

Of course, a faulty sensor will not go unnoticed and to see this, it is enough to pay attention to the behavior of your car. So, the obvious signs of a malfunction of the mass air flow sensor are:

1. Enabling the engine in emergency mode. You can find out about this by the corresponding lamp on the dashboard. Most often, it is orange, and may also contain the inscription "Check Engine".
2. The motor began to run erratically at idle. Many drivers refer to this phenomenon as "floating revs". Indeed, the speed can suddenly increase or decrease, and this process is rather chaotic.
3. The car began to accelerate worse. It is understandable, if the ratio of fuel and the correct volume of air is violated, the acceleration dynamics could noticeably worsen. In another way, this phenomenon is also called "stupid overclocking."
4. The amount of fuel consumed is increasing. This always happens when the engine goes into emergency mode.
5. Motor starts badly. Sometimes you have to turn for a long time, and in some cases even press the gas pedal. It happens that the engine does not start at all.

In addition, another reason for assessing the condition of the DMRV is a damaged air hose, a too dirty filter, as well as a violation of the integrity of the housing. In this case, the mass air flow sensor could simply be clogged, so try to clean it, eliminate all existing malfunctions, and then check the operation of the engine.

Troubleshooting

There are many ways to assess the condition of the mass air flow sensor. If there are any signs of a malfunction, you can use one of the methods below:

1. Start the engine, then disconnect the MAF connector by pulling out the chip. As soon as the engine goes into emergency mode, the speed will increase to 1500. This method helps to determine the status of the sensor, if it is not entirely known whether it is working or not.
2. You can try to install a known-good one instead of the old air flow sensor. If you notice any improvement in engine performance, then you need to change the DMRV with a new one. This method the simplest, but it is not always possible to find a known-good device, and a new sensor costs a lot of money.
3. Unscrew the sensor fasteners and remove it. A visual inspection will help verify its cleanliness. A good air mass sensor should have a whole wire and no traces of contamination. If any foreign particles are found, clean the sensor and try to install it again.
4. If you recently installed a new software into the controller, it is necessary to start the motor, and then put a small shutter in the form of a sheet of cardboard, etc. between the sensor and the filter. In normal mode, the rpm should increase, at which point you should remove the cover sheet as quickly as possible. In the event that the speed has not decreased, and the engine continues to work, then the malfunction lies not in the sensor, but in the new firmware, which simply does not monitor the operation of the DMRV.
5. The last method is the most informative, but to use it, you must have some knowledge of electrical engineering and have measuring device- multimeter. To do this, set up a voltage measuring device and set the maximum value to two volts.

The mass air flow sensor has two wires, one of which is green - "mass" and yellow, which sends necessary information per controller. The task is to determine the voltage flowing through the sensor. To do this, attach the black probe to the “ground”, and the red one to the contact of the yellow wire. At the same time, it is necessary to without fail turn on the ignition so that voltage goes through the DMRV. Based on the data obtained, it can be concluded that the air sensor is in good condition.

The mass air flow sensor (DMRV) is attached to the air filter and determines the amount of air passed through it. The quality of the combustible mixture depends on the correct determination of this indicator. Malfunctions will immediately affect the operation of the engine.

Signs of damage

At the first sign of a malfunction in the engine, do not panic, rush to the store and take a new DMRV. It may be assumed that the mass air flow sensor is damaged. How to check its work? First, you need to listen carefully to the car. He himself will indicate that the DMRV sensor is faulty, and will behave as follows:

The computer will give a "Check Engine" error;

The power will decrease;

Fuel consumption will increase;

The engine will start badly;

The dynamics will decrease.

What should I do if the mass air flow sensor does not work correctly? How to check its status?

Option 1: Shutdown

With the engine off, disconnect the connector from the MAF. The device will turn off, the controller will enter emergency mode, and the fuel mixture will be prepared taking into account the current throttle position. The engine will again report the transition to this mode, it must keep the speed over 1500 rpm. The final conclusions about the malfunction of the DMRV can be drawn if, when driving, you realize that after turning off the sensor, the dynamics have improved. Note: ECU modifications Ya-7.2 and M-7.9.7 after turning off the DMRV will not increase engine speed.

Option 2. Firmware

It is possible that the ECU has already been modified by firmware, then it is not entirely clear how it will behave when using the option above. In this case, the mass air flow sensor may also not work correctly. How to check it? Take a plate 1 mm thick and insert it under the damper stop. After we have risen, disconnect the terminal from the DMRV. If the engine continues to run, then the causes of the malfunction are in the computer, namely in the IAC steps. They do not respond to emergency mode without DMRV.

Option 3. Diagnostics with a multimeter

This option is acceptable for diagnosing Bosch sensors with indices: 0 280 218 004, 0 280 218 116, and 0 280 218 037. On the tester, set the measurement limits to 2V, in constant voltage mode. (orientation from salon):

Signal input - yellow;

Sensor power - gray-white;

Grounding (minus) - green;

To the main relay - pink-black.

Note:

The colors of the wires are indicated for most models, the colors may vary, but the meaning of the conclusions is the same.

Measurement procedure

After turning on the ignition, without starting the engine, we scan. The red probe of the device is connected to yellow wire DMRV, and black to green. So we measure the voltage and fix it. Comparing the obtained readings with the manufacturer's recommendations, which will allow us to judge the performance of the device. The new DMRV has a voltage of 0.996-1.01 V.

Device performance parameters depending on voltage:

1.01-1.03 - the sensor is operational;

1.03-1.04 - operational, but the sensor resource is almost exhausted;

1.04-1.05 - the resource is exhausted, if there are no signs of a malfunction, you can operate it, but it's time to purchase a new one;

1.05 and more - defective, replacement required.

Note:

To check the mass air flow sensor, you can find out about the "voltage from sensors" parameters.

Option 4. Visual inspection

We unscrew the clamps with a screwdriver, retracting the corrugation, inspect the sensor and the corrugation. All surfaces must be dry and free of oil deposits and condensation. Causes of contamination of the DMRV:

Dirty air filter;

The oil level is too high;

Clogged ventilation system.

Having eliminated the causes of contamination of the DMRV, it is necessary to correct the consequences, and this will require cleaning the mass air flow sensor. Using a 10 wrench, unscrewing the sensor mounting bolts, we separate it from the air filter. The sensor must have a rubber ring to prevent the suction of untreated air. If missing or out of place, the input grid of the device in question will be covered in dust. This may cause the sensor to malfunction.

Installation sequence:

A sealing gum is put on the device;

The sealing skirt is checked;

The sensor is installed in the filter housing.

Replacement procedure

Turning off the ignition, remove the plug from the sensor. After loosening the clamps, disconnect the air inlet pipe. Next, unscrew the sensor and remove it from the filter housing. To unscrew it, you need a key for 10. After inspection, the question will again arise about if the mass air flow sensor is faulty, how to check its performance. Having assessed the condition of the device during diagnostics, you should not immediately purchase a new one. It should be said that the cost of the DMRV ranges from 1500 to 2000 rubles. But you can simply eliminate pollution and spend a maximum of 200 rubles.

Decontaminants

In order to qualitatively wash the DMRV, it must be removed, the removal procedure has already been described earlier. There is a mesh inside the device. 2-3 sensors are installed on it, in the form of small wires. During operation, the parts are contaminated, which leads to a malfunction. To give a second life to the device, it is necessary to clean the mesh and sensors, for this a carburetor cleaner is suitable. Spraying the product, wash off the dirt from the inside of the DMRV. Complete elimination of contaminants may not occur the first time, the procedure will have to be repeated. All subsequent sprays should be carried out after the product has dried. When cleaning the sensor, it is worth inspecting the condition of the nozzles - if there is contamination, remove them. The use of a carburetor cleaner shows that 8 out of 10 devices begin to function correctly after treatment. But in some cases, you have to buy a new DMRV sensor.

Conclusion

Now check the DMRV on their own can be considered completed. And the questions about whether the mass air flow sensor is working, how to check its condition, they will be able to answer with a 100% guarantee at the service station by conducting a diagnostic examination using special equipment.