Every car owner knows that the operation of systems is controlled by special sensors. They are located in different places of the mechanisms. If such elements fail, the likelihood of malfunctions in the operation of system elements increases. In this case, repairs will be expensive. To eliminate the possibility of such a problem, periodically check the system sensors.

Control devices are responsible for the operation of many components and mechanisms. They need to be able to control them correctly. How to check temperature, pressure, air and other types of sensors will be discussed in detail in the article.

Sensor operation

Before you familiarize yourself with the technology of how to check the sensor idle move, oil pressure, temperature and other types of control devices, you need to consider the features of their operation.

The main devices of this type monitor the functioning of the motor and related systems. It is the engine that needs precise control of the operation of its elements and systems. Its failure entails the need for overhaul. To avoid large financial costs, it is recommended to check the performance of the sensors.

Control devices are responsible for testing the heating level of the system and coolant. They provide measurement of the condition of various components during idling, in normal mode, etc. Every car owner should know how to check the temperature, air, oil pressure and other similar devices.

temperature sensor

There are a number of recommendations on how to check sensors on a VAZ, Chevrolet, Mercedes and other brands of cars. One of the most important indicators is a device that measures the heating of the coolant. This device transmits the collected data on the state of antifreeze to the engine control unit. He, in turn, adjusts his work based on the data received. In this case, the correct fuel supply level and ignition angle are adjusted.

On many cars (including VAZ, Kalina, Priora, Granda, etc.), the temperature control sensor switches the system to the electric ventilation type of cooling. Its readings are often displayed on the dashboard. This allows the driver to monitor the condition of the engine and its antifreeze. Modern vehicle models are equipped with temperature control sensors that have a negative heating coefficient. This means that as heating increases, the resistance of a given element decreases.

Operating principle of the temperature sensor

When considering how to check engine sensors, you need to study the basic principle of their operation. One of the most important things in the system is the antifreeze temperature control device. The control unit sends an electrical signal to this sensor. It has a voltage of 9 V. When this happens, the reader takes a resistance reading at the sensor contacts. The system sends this data back to the control unit. At the same time, she will be able to calculate, using a given logarithm, how the engine should operate under such circumstances.

If the temperature has increased, the resistance should decrease. In this case, the system, using its special mechanisms and electronic devices, regulates the level of fuel consumed during engine operation. This allows you to reduce the heating temperature at the right time. Antifreeze in this case will be able to properly cool the system. When the temperature drops significantly, the presented mechanism will help adjust the engine operation in the opposite direction.

How to remove the sensor?

When considering how to check the coolant sensor, you need to know the correct element of the system. Drivers often confuse this element with the device that controls the fan. You don't need to look for it on the back of the fan. The temperature sensor is almost always installed in one of two possible locations. In the first case, an antifreeze heating control device can be installed near the thermostat. Moreover, it can be located directly in its body. In the second case, the sensor is installed in the cylinder head. It should be located in close proximity to one of the cooling system pipes.

To dismantle, you will need to drain the antifreeze from the radiator. Next, remove the air filter if the car is of the injection type. You can unscrew the sensor using wrench. In foreign cars, dismantling can be more difficult. Often the sensor is located at the rear of the cylinder head. In this case, during dismantling you will have to disconnect several hoses.

Checking the sensor operation

The method for checking the temperature sensor is described in detail by the manufacturer. vehicle. To carry out such work, you will need tools, a tester, a container of water, a stove, a thermometer with divisions up to 120 ºС, and a basin for antifreeze. First you need to turn off the radiator and drain the antifreeze from it. After this, the sensor is dismantled. The container with water must be placed on a gas or electric stove. The sensor must be lowered into the liquid. Its brass part should be completely immersed in water. The plastic should be on top.

You need to connect a tester to the device connectors. It is turned on in resistance measurement mode. Next, you need to heat the water and record the multimeter readings. You need to study the manufacturer's instructions, which indicate the operating parameters of the sensor. Most often, at a temperature of 100 ºС, the resistance is 150-200 Ohms. When the temperature drops to 20 ºС, this figure should increase to 3-4 kOhm. This indicates that the sensor is working properly. Otherwise it will need to be replaced.

Idle speed sensor

Drivers may be interested in how to check a car's idle speed sensor. This device is also responsible for ensuring stable engine operation. It only controls this process at idle. This sensor controls the amount of air that is supplied to the motor in this operating mode.

In this case, it is no longer the antifreeze liquid that is measured. The idle air supply system has certain components. It has a valve in the form of a conical needle. This element prevents air from entering the system. The needle is driven by a small motor that runs on electricity. The damper is set in motion when the motor is turned on. The needle can open or close the gap through which air enters the engine. Moreover, the diameter of this hole is also adjustable due to the special configuration of the damper.

Signs of malfunction

Before air, you should consider under what circumstances you need to suspect a malfunction of this particular element of the system. If the control device fails, the car will stall when stopping at traffic lights. In this case, the driver will have to hold the gas pedal while waiting for the green light.

Unstable engine speed also indicates a malfunction of the idle speed sensor. This can be heard even without the use of special equipment. It also takes a long time to warm up the engine. Even in warm weather, starting a car becomes problematic. Even after warming up, you have to drive on “choke” for a long time. The driver may also notice that when the transmission lever is moved to neutral, the engine begins to operate unstably. At the same time, it may even stall. In this case, you will need to check the idle speed sensor.

Checking the idle speed sensor

If the listed malfunctions appear, you need to consider how to check the idle speed sensor. It is located on the throttle valve. Her cable is attached next to it. Above the idle speed sensor is a throttle position control device. You need to turn off the ignition and dismantle the presented device. The sensor can be attached using adhesive or bolts. In the first case, you will need to dismantle the entire throttle assembly. The bolted connection will allow you to disconnect only the sensor.

Next you need to connect the wires to the sensor on-board network. You need to place your finger on the conical needle. Next, the ignition is turned on. If after this you feel slight jolts of the needle, then the sensor is working. Otherwise, this structural element will be motionless. The sensor will need to be replaced.

Checking the oil pressure sensor

A malfunction of the oil pressure sensor can lead to engine malfunction. Therefore, it must be periodically checked for functionality. How to check the oil pressure sensor? There is a certain technology for this. It involves dismantling the control device. Next you need to connect the multimeter contacts to the sensor. It shows zero resistance. Next, use the pump to pump the oil. The chain must break. In this case, the device shows infinity. This indicates that the sensor is fully operational. Knowing how to check sensors, you can ensure normal operation of the motor and all systems for a long time.

All modern cars equipped with an electronic engine management system that regulates the operation power unit using information collected from special sensors. One such device is an air pressure sensor or MAP sensor installed in the intake manifold. It reacts to all changes in pressure during the intake stroke, and the engine ECU, depending on the instrument readings, ensures the preparation of the optimal combustible mixture.

Purpose and principle of operation of the absolute pressure sensor

A pressure sensor is designed to measure absolute pressure, that is, air pressure relative to vacuum. The data obtained is used by the engine control system to calculate air density and flow rate to optimize the preparation of the air-fuel mixture. The device acts as an alternative to an air flow meter, and in some car models it works in conjunction with a flow meter.

Modern sensors use two measurement technologies: micromechanical and thin film. The first is more progressive, as it produces more accurate measurements, and most sensors are made according to it. If the engine has a turbocharger, an additional sensor is installed between the compressor and the manifold to regulate the boost pressure depending on the needs of the engine, which is structurally identical to the DBP.

The design of the air pressure sensor has 2 chambers - atmospheric, connected to the intake manifold, and vacuum. There are also 4 strain gauges attached to the diaphragm and an electronic chip. Air pressure acts on the diaphragm, and it moves strain gauges, which, depending on the position, change resistance, which ultimately affects the magnitude of the impulse from the chip to the control unit.

Sensitive semiconductors to increase the pulse are connected in a bridge circuit, and the outgoing voltage varies from 1 to 5 V. The resulting voltage allows the ECU to determine the pressure in the intake manifold - the higher it is, the higher the indicator is considered. Based on the type of sensor, it produces different type signal - digital or analog. An analog-to-digital converter is additionally installed in the analog device.

The sensor obtains air pressure results as follows:

1. The air flow in the manifold puts pressure on the diaphragm of the device, and it bends.
2. When the diaphragm is mechanically stretched, the resistance on the strain gauges changes, that is, a piezoresistive effect is observed.
3. The voltage changes in proportion to the resistance of the strain gauges.
4. The semiconductors in the sensor are connected in a bridge circuit and are very sensitive. Electrical diagram, located in the device, amplifies the bridge voltage, as a result, at the output it varies within 1-5 V.
5. Based on what output voltage enters the control unit, the pressure level at the inlet valve is calculated. More high voltage corresponds to higher pressure.

Symptoms of a malfunctioning absolute pressure sensor

The following signs indicate a DBP malfunction:

1. Increased fuel consumption. The device supplies the control unit with data about high air pressure, which is actually much lower. For this reason, the control unit supplies a rich mixture to the cylinders.
2. Engine dynamics drop and do not improve when warmed up.
3. When the motor is running from exhaust pipe there is a smell of fuel.
4. A running engine produces white exhaust even in the warm season.
5. The engine does not slow down for a long time when idling.
6. When changing gears, the car jerks noticeably.
7. Unstable engine operation in all operating modes, presence of extraneous noise, often turning into hum.

Possible causes of malfunction

The absolute pressure sensor is a fairly reliable device, but sometimes it fails, causing the engine to switch to emergency mode, and even preventing the engine from starting. There are several reasons for problems with DBP operation:

1. Poor connection between sensor and inlet fitting.
2. Coked pipeline, which has a fairly flexible design.
3. Failure of the air temperature sensor, which is connected to the DBP, and sometimes combined with it in one housing.
4. Depressurization of the vacuum hose due to damage or disconnection from the sensor.
5. Broken ground contact.
6. There is a fault inside the sensor.

Checking the absolute pressure sensor

In different car models, the sensor design may differ, and, therefore, the verification algorithm may also differ. The following general instructions will allow you to explore most types of devices. For this you will need:

1. Simple vacuum pressure gauge.
2. Tester or voltmeter.
3. Vacuum pump.
4. Tachometer.

Checking the air pressure sensor consists of the following steps:

1. To check the analog sensor, its adapter is connected to the vacuum hose between the pressure sensor and the intake manifold. A pressure gauge is also connected to the adapter.
2. Start the engine and let it run for a while idle speed. When the vacuum in the manifold is less than 529 mm Hg. Art., check the integrity of the vacuum hose, since some of the air is lost due to damage to it. You should also pay attention to the condition of the sensor diaphragm, which may contain both factory defects and defects acquired during operation.
3. After taking the pressure gauge readings, it is replaced with a vacuum pump, after which a vacuum of 55-56 mm Hg is created. Art. and stop pumping. If the sensor is working properly, the vacuum will remain for 25-30 seconds. If the requirement is not met, the sensor must be replaced.
4. When checking a digital sensor, use a tester in voltmeter mode.
5. Turn on the ignition, find the grounding and power contacts. A wire connected to the signal contact of the sensor being tested is connected to the voltmeter. During normal operation, the voltage will be about 2.5 V. If there are malfunctions, it will differ up or down.
6. The tester is switched to the tachometer operating mode and the vacuum hose is disconnected from the DBP. The positive input is connected to the signal wire, and the negative input is connected to ground. If the sensor is working properly, the tachometer will give a result of 4400-4850 rpm.
7. Again, a vacuum pump is used, which is connected to a pressure sensor. The pump constantly changes the vacuum in the device and monitors the tachometer readings. If the sensor is working properly, the vacuum and tachometer readings will be stable.
8. When the vacuum pump is turned off, the tachometer stops at 4400-4900 rpm. If the readings differ from those indicated in one direction or another, the sensor is faulty.

Repair

After diagnosing the DBP malfunction, they begin to eliminate it. In the event of a minor breakdown that can be repaired, the device is left behind. If the device gives incorrect readings, it needs to be completely replaced. The design of the sensor is not designed for repairs, and all actions directed by the technician to eliminate malfunctions are carried out at his own peril and risk. But the cost of the new device is quite high, and all manipulations, if successful, become justified.

Repair of the sensor is carried out in a certain sequence:

1. Use a knife or other sharp tool to remove the cover of the device, after which the location of the fault is identified.
2. The contacts are cleaned of dirt and rust, the reliability of their connection is checked, and after cleaning they are dried, filled with silicone sealant, and dried again. All joints on the assembled device are sealed with sealant.
3. The device is installed on the car and its serviceability is checked. Quick engine start and smooth operation mean the device is in good working order. If the repair does not bring the expected results, the sensor is replaced with a new one.

Imagine the situation: you are the owner of an Android smartphone, the device received an important call, during the call the device’s screen turned off and does not come out of its state even when you move the smartphone away from your head. The reason for this is an inoperative proximity sensor. How to find out about this? Check with Sensor Box.

This is a real life example and it is with the help of this application that you can find the cause of the problem.

In addition to testing the proximity sensor, there is an accelerometer test where the user controls a virtual ball on a wooden board. The light sensor test displays the amount of light received, measured in lux.

You can also check the performance of the gyroscope and microphone; in the latter case, the noise level, measured in decibels, is determined.

In the magnetic sensor test, you can view the strength of magnetic fields, measured in microtesla. The upper limit is a value of 200 µT. At this stage, the functionality of the Sensor Box is completed. There are, of course, tests of temperature and pressure sensors, but not every device can boast of having them.

The main disadvantage may be the outdated interface. Let's face it, it feels like the developers simply forgot about the existence of the project, because the interface here is straight from 2009, when devices running Android 2.3 were popular. Although, of course, the Sensor Box still performs the main task, and its appearance complies with the guidelines.

Hall Sensor

Need check hall sensor occurs when problems arise with the car’s ignition system, and therefore it is necessary to ensure that all its components are in good working order, in particular the idle speed sensor. So let’s take a closer look at the principle of operation, signs of malfunction and how to check the Hall sensor with your own hands.

The principle of operation of the sensor and its features

In its operation, the sensor uses the physical Hall effect, discovered in the 19th century. However, they began to use it only in the 70-80s of the last century, when automakers began to switch from electronic ones.

Simple enough. As the motor shaft rotates, metal blades pass through slots in the motor housing. It gives an electrical impulse to the switch, as a result of which the latter unlocks the transistor and supplies voltage to the ignition coil. It, in turn, converts the low-voltage signal into a high-voltage one and supplies it to the spark plug.

Structurally, the sensor has three contacts:

• for connection to “ground” (car body);
• to connect voltage with a “+” sign and a value of about 6 V;
• to supply a pulse signal from it to the switch.

Advantages of using a Hall sensor in electronic ignition systems there are two main factors - lack of contact group(which constantly burns), and also higher spark plug voltage ignition (30 kV versus 15 kV).

Since Hall sensors are also used in braking and anti-lock braking systems, the operation of the tachometer, the device performs the following additional functions for the machine:

• increases engine performance;
• speeds up the functioning of all machine systems.

As a result, the ease of use of the car, as well as its safety, increases.

Hall sensor for VAZ 2107

Hall sensor for VAZ 2109

Hall sensor for VAZ 2110

Signs of a Hall sensor malfunction

Sensor failures manifest themselves in different ways. Identifying them can sometimes be difficult even for an experienced master. Here are some of the most common symptoms and problems with the Hall sensor:

• hard to start or the engine does not start at all;
• occurrence of interruptions in engine operation;
• “twitching” cars when driving at high speeds;
• the engine stalls while the car is moving.

If one or more of these symptoms appear on your machine, it is imperative to check the sensor.

How to check the Hall sensor

Exists several verification methods. Briefly, they work like this:

Checking the serviceability of the hall sensor (diagram)

• Creating a simulation of the presence of a Hall sensor. This verification method the fastest and it will be suitable if there is power at the ignition system components, but . For this purpose, the three-pin block is removed from the distributor. Next, you need to turn on the car’s ignition and connect (short with a piece of wire) outputs 3 and 2 (negative pin and signal contact). If in the process on the central wire of the ignition coil there will be a spark- Means, the sensor has failed. Please note that in order to detect sparking, you need to hold the high-voltage wire near ground.
• Checking the Hall sensor with a multimeter, the most common method. For this check, a multimeter (tester) is used. To do this, it is enough to measure the voltage at the output of the sensor. If it is working properly, then the voltage should be within the limits 0.4...11 V.
• Replacing a faulty device with a known working one. You can borrow it from friends who have a car with the same sensor. If after replacement the problems that bother you disappear, you will have to buy and replace the Hall sensor with a new one.

Checking the Hall sensor

Hall sensor, checked with a multimeter.

Another common method is to check for resistance at the sensor. To do this, you need to make a simple device consisting of a 1 kOhm resistor, an LED and flexible wires. A resistance is soldered to the LED leg, and two wires of a length that is convenient for operation (not short) are soldered to it.

Then remove the distributor cover, disconnect the distributor and plug box. Next, check the functionality electrical circuit. To do this, an electronic multimeter (voltmeter) is connected to terminals 1 and 3, after which the car ignition is turned on. Under normal conditions, the value obtained on the screen of the measuring device should be within the limits 10...12 V.

Next, we similarly connect the constructed device to the same terminals. If you guessed the polarity correctly, the LED lights up. Otherwise, the wires must be swapped. The further procedure is as follows:

• do not touch the wire connected to the first terminal;
• we transfer the end from the third terminal to the free second one;
• rotate the camshaft (manually or using a starter).

If the LED blinks while the shaft is turning, then everything is in order and the Hall sensor does not need to be replaced.

It is worth noting that the process of checking the Hall sensor on the VAZ 2109, Audi 80, Volkswagen Passat B3 and other cars is carried out according to the same scheme. The only difference is the location of individual parts under the hood of the car.

Hall sensor replacement

Replacing the Hall sensor VAZ 2109

Let's consider the process replacing the Hall sensor on a VAZ 2109 car. This procedure is simple and does not cause difficulties even for novice car enthusiasts. Its algorithm is as follows:

• The first step is to remove the distributor from the car.
• After this, the distributor cover is dismantled. Next, you need to align the marks of the timing mechanism and the crankshaft mark.
• Then the fasteners are dismantled using a wrench. At the same time, do not forget to mark and remember the location of the distributor.
• If there are latches or stoppers in the housing, they must also be removed.
• At the next stage, remove the shaft from the distributor.
• Next, disconnect the Hall sensor terminals and unscrew the mounting bolts.
• The sensor is removed through the resulting gap.
• Installation of a new Hall sensor is carried out in the reverse order.

Conclusion

It is worth noting that there is no point in repairing the Hall sensor, since it is very inexpensive (about $3...5). If you are convinced that the car’s malfunctions are related specifically to the mentioned sensor, we recommend that you go to the nearest auto store and buy a new device. If you encounter any difficulties when checking or replacing the Hall sensor, seek help from the technicians working at the service station.

Engine load, road surface condition, vehicle load are some of the few factors that determine engine operating modes. internal combustion. The very first and strict rule that determines the optimal conditions for engine operation is the correct correspondence of the amount of air to fuel, the standard of which is 14.7 kg of air per 1 liter of gasoline.

The main task of the sensor is to measure the ideal amount of incoming air so that the engine efficiency is as high as possible.

DMVR: what is it?

Mass air flow sensor is a hot-wire type sensor that reads information about the amount of air that enters the intake manifold, which allows the electronic engine management system to calculate the correct fuel-air mixture ratio. This sensor is installed between the air filter housing and the intake manifold, and a corrugation connects them.

DMVR - hot-wire sensor

Before servicing or repairing, it is necessary to understand the design of this sensor.

The air flow sensor consists of 6 parts:

1. 1. Pay.
2. 2. Frame.
3. 3. Radiator.
4. 4. Sensor (sensitive element).
5. 5. Pipe branch.
6. 6. Inlet and outlet screens.

The main part of the mass air flow sensor is a nickel network or wire (sensitive element), to which a current is supplied that heats the filament. The average temperature of the threads is 75-100 degrees or higher than the temperature of the air passing by the sensor.

How to check the mass air flow sensor with a multimeter and other methods

Immediately before checking the malfunction, you should understand the symptoms. 5 of these have been identified:

1. 1. The Check Engine lights up on the instrument panel (indicating some kind of engine malfunction).
2. 2. A sharp increase in gasoline consumption.
3. 3. Late response to the gas pedal, dynamics decreases.
4. 4. At operating temperature the engine does not start.
5. 5. Loss of power.

The question arises: is it possible to drive when a malfunction of the mass air flow sensor is detected?

When the sensor is disconnected from the power supply, the engine begins to operate in emergency mode. The fuel to air ratio now depends on the throttle opening angle, which increases gas mileage. Minimum frequency crankshaft revolutions start at 1500 rpm.

There are 5 ways to check the operation of the sensor.

Method No. 1: disconnect power from the mass air flow sensor

It is necessary to remove the connector from the sensor and start the engine. In this case, the “Check Engine” should light up, the minimum speed will increase to 1500 rpm. If you feel the speed of a car without a sensor, then this is a direct sign of a non-functioning air flow sensor.

Method No. 2: Reflashing the control unit.

In case the firmware of the “brains” was previously carried out, then it is impossible to know how the engine is programmed for an emergency in the first method. It is necessary to take a plate 1 mm thick and place it under the damper stop. The engine speed should increase. Then you need to remove the connector from the sensor. If the engine does not stall, it means that the problem lies in the firmware of the control unit, namely with the idle speed controller without a mass air flow sensor in emergency mode.

Method No. 3: Checking the sensor using a multimeter

This method does not work on all mass air flow sensors. You need to set the tester to measure direct current and put a maximum of 2 V.

There are 4 wires suitable for the sensor, each marked with its own color, starting from the one closest to the windshield:

1. The yellow wire is responsible for the input of the air flow sensor signal.
2. Gray wire (white) – supply voltage output channel.
3. Green wire – ground.
4. The black wire (with a pink stripe) is responsible for the output to the main relay.

The colors on the mass air flow sensor may be different, but the location of the pins is the same in all.

Next, turn on the ignition, but do not start the engine. Touch the red probe to the first wire (yellow), the black probe to ground (green wire). This method shows the voltage between two wires.

The new sensor voltage should be between 0.99 and 1.01. If the voltage begins to increase over time, this means that the sensor is rapidly wearing out.

Voltage indicators:

— 1,01 – 1,02 V– The air flow sensor is in excellent condition;

— 1,02- 1,03 V- satisfactory condition;

— 1,03 – 1,04 V– the resource of the part is almost exhausted;

— 1,04 – 1,05 Vand higher - the mass air flow sensor needs to be replaced.

Method number 4: inspection of the sensor

It is necessary to remove the mass air flow sensor from the seat by disconnecting it from the air filter housing and bellows. The inner surface of the sensor must be dry, without traces of condensation and oil. Frequent sensor failure occurs because the air filter is rarely changed, dirt gets on the sensitive element, and it gives erroneous readings. The presence of oil in the sensor indicates an increased oil level in the engine or clogging of the crankcase ventilation.

Next, you need to make sure that the sealing ring on the seat where the corrugation fits is not stuck on the air filter housing. If this happens, then air leaks from the seat, which pulls dust with it, which causes rapid wear of the sensor.

Method No. 5: installation of a similar sensor.

If it is possible to take the same mass air flow sensor, then using an example of its operation you can draw conclusions about the performance of your sensor.

What are the dangers of malfunctions?

1. Increased gasoline consumption.
2. Unstable engine operation.
3. The engine will not operate at temperatures above 90 degrees.

Troubleshooting

The peculiarity of the air flow sensor is that it is maintenance-free and cannot be repaired. It is only allowed to be cleaned. It is strictly forbidden to blow the sensor with compressed air, clean it with ether, acetone, swabs and cotton swabs, as these operations can damage the sensitive element. There are special “Flow meter cleaner” flushes that extend the service life of the part, provided that its voltage does not exceed 1.13V.

Is it possible to installsensor from another car brand

Flow meters are manufactured specifically for each engine, as a result of which they also have different output voltages. If a foreign sensor is installed, the engine control unit will not be able to properly process the sent signals, which will affect the stability of the engine.

If there is no other way out, then the ECU can be flashed for someone else’s flow meter, provided that this operation is carried out by a specialist.

Video: how to check the DMRV with a multimeter

Bottom line

The mass air flow sensor is an integral part of the intake and fuel system, which indicates how much fuel to supply at a certain moment. Its malfunction can have a detrimental effect on the operation of the motor. In order to maximize the life of the sensor, it is necessary first of all to monitor the parts that are directly related to it (the condition of the air filter, the oil level and the condition of crankcase gas suction clogging). The average service life of a mass air flow sensor with proper care can be over 50,000 km or two years.