How does the car behave if the lambda probe does not work. Lambda probe: causes of malfunction Causes of a faulty lambda probe

Do you want to know the symptoms of a malfunctioning lambda probe? You have come to the right place. By the way, this site most often worries the minds of owners of foreign cars, but first things first. But in general, the essence for which the sensor is used is to probe the exhaust gases.

European automakers, under the yoke of environmentalists and new bills that require limiting the emission of harmful substances into the atmosphere, are resorting to the use of various new units in every possible way. Most often these are various neutralizers or catalysts - devices that actively reduce the amount of harmful substances in the exhaust of a car.

The main functions of the lambda probe

As noted above, for a longer catalyst life, tight control over the quality of the air-fuel mixture is necessary. The lambda probe takes its name from the Greek letter, in the automotive world, this letter marks the coefficient of excess air in the fuel mixture entering the engine.

Catalysts can only operate within a very narrow range of the correct fuel to air ratio. Small deviations make these devices useless. Therefore, it is so important to observe this proportion to tenths. Now you understand that such accuracy in calculating proportions, tracking processes and catalysts are all the prerogative of foreign cars. Russian cars are not yet operated within such a strict restrictive framework as foreign cars.

Principle of work

Inside the device, you can find a galvanic cell consisting of a solid electrolyte inside (zirconium dioxide). Various coatings, in the form of conductive materials such as platinum. One of the electrodes is located in the zone of exposure to exhaust gases, and the other is in the ambient air.

Malfunctions

(banner_content) The lambda probe performs the complex function of a controller in the exhaust cycle. The easiest way to check the quality of the unit is to measure the exhaust gases. This can be done using a special stand at service stations. If the indicator differs from that declared by the manufacturer, then most likely, the sensor ordered to live long.

Usually, the percentage of rejection of harmful substances can reach up to 4%... This problem can be observed on old engines, where the motor itself is already running with its last bit of strength. Extra additives and additives appear in the fuel mixture. The catalysts do not cope with the work and as a result, the entire system begins to produce an increased amount of pollutants into the atmosphere.

In addition to measuring emissions in the exhaust of a car, there are indirect signs that indicate a malfunction of the probe.

For example, if you notice negative change in the dynamics of acceleration(acceleration has worsened). Also, if the engine starts to run at idle speed, the revolutions jump, the reason may lie in the breakdown of the probe. If you carefully monitor the amount of fuel consumed, then its increase may indicate a known cause. It is recommended to replace the lambda probe on a modern foreign car every 100 thousand kilometers.

Manufacturers note that cars operated in cold conditions without warming up require replacing the lambda probe much more often than warmed up ones. This indicator can double the difference! Therefore, we strongly recommend warming up the car without load, especially if it has been standing for a long time at very low negative temperatures.

The main reason for the failure of the probe is carbon deposits.... It meets under the protective cap, covering the sensitive areas of this device. By the way, if it is possible to remove carbon deposits, then the unit will start functioning and it will not have to be replaced with a new one (save money).

For cleaning, you can use phosphoric acid by placing the device in it for 15 minutes or better, smearing it on the contaminated area.

Testing the probe

It will not be superfluous if you test this sensor at least every 35 thousand kilometers. If you are measuring, remember that the probe needs time to warm up to operating temperature. The symptoms of a malfunctioning lambda probe listed above will help save time and money. Exhaust gas measurements are carried out by some dealers, where you can also get some recommendations.

Sensor. Symptoms of malfunction of this device will make you think about replacing it. Because the first sign is a significant increase in gas mileage. The reasons for this behavior will be discussed below. And first, it is worth talking a little about the history of the creation of this device, as well as about its principles of operation.

The need for an oxygen sensor

And now about what an oxygen sensor is needed for in a car. Symptoms of its malfunction will be discussed later. When burning any fuel, oxygen must be available. Without this gas, the combustion process cannot take place. Therefore, oxygen must enter the combustion chambers. As you know, a fuel mixture is a mixture of gasoline and air. If you pour pure gasoline into the combustion chambers, the engine will simply not work. By how much oxygen remains in the exhaust system, we can say how well the air-fuel mixture burns in the engine cylinders. It is to measure the amount of oxygen that a lambda probe is needed.

A bit of history

At the end of the 60s, for the first time, car designers began to try to install these sensors on cars. The very first oxygen sensors were installed in Volvo cars. also called a lambda probe. The fact is that there is a letter "lambda" in the Greek alphabet. And if you turn to the reference literature on internal combustion engines, you can see that this letter denotes the excess air ratio in the fuel mixture. And this parameter allows you to measure

Principle of operation

The oxygen sensor is installed exclusively on injection vehicles that use electronic engine control units. The signal generated by it is fed to the control unit. This signal is used by the microcontroller in order to make the correct mixture adjustment. It regulates the air supply to the combustion chambers. Of course, the quality of the mixture is influenced not only by the signal from the oxygen sensor, but also from most other devices that measure the load on the engine, its rpm, as well as the speed of the car, and so on. Often two lambda probes are installed in cars. One is a worker, and the other is for corrections. They are installed before and after the collector. Pay attention to the fact that the lambda probe, which is mounted after the collector, has additional forced heating. Before cleaning the oxygen sensor, be sure to read the manufacturer's requirements.

Operating conditions of the lambda probe

It is also worth considering that the most effective functioning of this sensor occurs at temperatures from 300 degrees and above. It is for this purpose that an electric heater is needed. It allows the oxygen sensor to function normally when the engine is cold. The sensing element of the sensor must be located directly in the exhaust gas stream. So that its electrode, located on the outside, is necessarily washed with a stream. The inner electrode must be placed directly in the atmospheric air. Of course, the oxygen content is different. And between these two electrodes some potential difference begins to form. A maximum voltage of 1 volt may appear at the output. It is this voltage that is supplied to the electronic control unit. That, in turn, analyzes its signal, then, according to the fuel map embedded in it, increases or decreases the opening time of the injectors, changes the air supply to the rail.

Broadband

There is such a device as a broadband sensor (UAZ "Patriot" has the same as any other car) sensors consist in the fact that the engine operating mode changes. The difference between a conventional and such a device is quite large. The fact is that they have completely different principles of functioning and sensitive parts. And broadband lambda probes are more informative, and this is important for cases when the engine operates in non-standard modes. Consequently, the richer the information, the more accurate the settings will be made by the electronic control unit.

How to identify a breakdown

It is worth noting that oxygen sensors affect the functioning of the motor very strongly. If suddenly the lambda probe orders to live for a long time, then the engine, most likely, will not work. When a lambda probe breaks down, no signal is generated at the output, or it changes in an unpredictable way. Of course, this behavior will greatly complicate your daily life. The sensor can fail literally at any minute. For this reason, cars are equipped with certain functions that allow you to start the engine and also get to the workshop, even if the oxygen sensor is faulty.

Emergency firmware

The fact is that when the electronic control unit sees a breakdown of the lambda probe, it starts working not according to the default firmware, but according to the emergency one. In this case, mixture formation occurs according to data obtained from other sensors. Only the oxygen sensor is not involved in this process. The driver will notice the signs of malfunction of this device immediately. Unfortunately, the mixture is too lean, as the percentage of gasoline is more than necessary. This ensures that the engine does not stall. But if you increase the air supply, then there is a high probability that the engine will stall. However, as a warning on most cars, the Check Engine lamp in the dashboard lights up, which signals about the literal translation of this inscription - "Check the engine". But even without it, you can determine the breakdown of the lambda probe. The fact is that fuel consumption increases significantly compared to the normal mode.

Conclusion

Now you know what an oxygen sensor (lambda probe) is, what properties and features it has. In conclusion, I would like to mention that this element is very picky about how it is installed. Make sure that there are no gaps between the sensor body and the collector, otherwise this will lead to premature failure of the device. In addition, during operation, the sensor will send incorrect information to the control unit.

Lambda probe is the traditional name for an oxygen sensor. With its help, the amount of oxygen in the exhaust gases is monitored. Engine performance is directly related to how efficiently the fuel-air mixture burns. And oxygen is largely responsible for the combustion process. By adjusting its content in the mixture, you can control the combustion temperature: by raising or lowering it accordingly. If there is a lot of oxygen in the mixture, then engineers usually denote this situation with the Greek letter lambda. Well, one cannot but agree that the "lambda probe" in Russian sounds much more expressive than the everyday "oxygen sensor".

The main tasks of the lambda probe

The oxygen sensor is installed where the exhaust gases pass, namely in the exhaust manifold. It is used in those cars that are equipped with an injector. To improve the accuracy of the estimate, sometimes two lambda probes are used. They surround him carefully, being on both sides of it.

The electronic control unit regulates the amount of fuel that is supplied to the engine. The oxygen sensor helps him in this. It transmits information about the oxygen content in the exhaust gases. Depending on the readings of the sensor, the amount of injected fuel increases or decreases. When there is too much oxygen in the mixture, its combustion temperature rises. At the same time, toxic substances are released that are dangerous to humans and the environment. The lambda probe indirectly controls the environmental friendliness of the exhaust system and seeks to create conditions for the proper operation of the catalyst.

Device

Oxygen sensors are of two types: point-to-point and broadband.

Point-to-point sensor has become traditional and is gradually becoming a thing of the past.

It consists of two electrodes: one inside, the other outside. The outer electrode is covered with a thin layer of platinum, which is susceptible to oxygen. The inside electrode is made of zirconium. The potential between the electrodes changes in response to the amount of oxygen in the mixture: the more oxygen, the higher it is.

Broadband sensor is becoming an increasingly popular variant of the lambda probe.

This uses two ceramic elements. One performs the function of a point-to-point, and the other performs oxygen injection. The mixture from the exhaust gases no longer just goes to the sensor for evaluation and analysis by itself, but the sensor deals only with oxygen, pumping it separately from the mixture. With a constant voltage of 450 mV, the sensor reacts to a decrease or increase in oxygen concentration by changing the voltage, which is immediately informed by the ECU. Having received the appropriate signal, the ECU generates a pumping current. Through the value of the pumping current, the oxygen content in the mixture is determined.

Effectively, the oxygen sensor only works at temperatures above 300 ° C, so all lambda probes are heated.

Symptoms of the disease

Problems with the lambda probe can manifest themselves as follows.

• The toxicity of the exhaust gases has increased and no longer meets the established standards. However, the car enthusiast himself cannot check this without a special device.

• Increased, but this problem may have many other reasons.

• The engine is idling. Unfortunately, this symptom is also ambiguous.

• The dynamics of the vehicle is impaired.

• A characteristic crackling sound can be heard in the area of ​​the catalyst.

• The "" light came on, but even here you will need to carry out diagnostics at the service center.

Ideally, a specialist should diagnose a breakdown of the lambda probe.

Causes of malfunction

The lambda probe can fail for the following reasons:

• Poor quality is the first enemy of all sensitive elements developed by foreign engineers in order to take care of the ecology of the environment. Due to lead deposits, the outer layer of the sensor loses its sensitivity and becomes inoperative.

• Mechanical stress that violates the design of the lambda probe leads to its breakage.

• Problems in the fuel system can provoke the formation of carbon deposits or soot on all elements of the exhaust system, which interferes with their proper operation.

• Overheating of the sensor can occur for various reasons, but, as with all sensitive elements, too high temperatures have a destructive effect on the nalambda probe.

• Getting into or into the exhaust system, as well as its leakage, also leads to a malfunction of the lambda probe.

If the sensor is out of order, then the ECU loses feedback with the exhaust system and works "blindly", according to the average parameters that are in its memory. At the same time, it is clear that the composition of the fuel-air mixture, going out of control, ceases to be optimal.

Lambda probe - vulnerable and relatively short-lived element... In the best scenario, after 60-80 thousand km, it fails.

Checking the lambda probe

Almost everyone can check an oxygen sensor. To check, you need to use one or two auxiliary tools: an oscilloscope and a voltmeter. If you do not know where the device is located, then use the manufacturer's instructions.

First, you should check the element for mechanical damage. Its body must be intact, as well as the wiring. If the sensor is not damaged, but dirty, then it is better to replace it with a new one. Of course, you can try to clean up carbon deposits and soot, as well as any other plaque. If it succeeds, good; if not, replacement is necessary.

Let's assume that our device is intact and has a clean surface. Then you should continue checking with a voltmeter or oscilloscope.

When the lambda probe is not needed

The oxygen sensor loses its value after removing the catalyst or replacing it with a flame arrester. In this case, we are talking not only about mechanical removal, but also about software. If it is possible to reprogram the ECU, then the need for a lambda probe disappears and you can forget about it. Otherwise, decoys are installed.

I must say that the lambda probe is not an expensive part (the average price of the part itself varies around 2,000 rubles + 500 rubles for work), so a failed sensor can be replaced with a new one. The main thing is to do this in a timely manner, while other elements have not suffered, in particular, the catalyst, the price of which is already completely different.

The exhaust system of the car is gradually being modernized. And this applies not only to the installation of catalysts and designed to purify gases from lead and other harmful substances. In addition, modern cars are equipped with an oxygen sensor. It is popularly called a lambda probe. What is an oxygen sensor? Replacement, inspection, malfunctions - further in our article.

Characteristic

Not every motorist knows what this element is for. A lambda probe is a sensor that reads information about the exhaust gas and transmits it to the ECU.

The information received is processed in the block, then the device balances the composition of the fuel-air mixture in order to align the order of its combustion in the cylinders.

Where installed, types

This element is located in the exhaust manifold (the so-called "spider"), where the pipes of the exhaust system are connected. In some cases, the sensor is installed closer to the catalyst. But this arrangement does not affect the overall performance of the device. There are several types of oxygen sensors:

• Broadband type.
• With a two-channel layout.

The latter were installed on old cars (up to the 90s of production). Modern cars are equipped with a broadband lambda probe. Such a sensor is able to accurately detect deviations in the composition of the exhaust gases and quickly balance this ratio by decreasing or increasing oxygen in the mixture. A serviceable sensor can reduce fuel consumption. Also, his work is aimed at maintaining optimal idle speed.

Why does the oxygen sensor fail ("Kalina")

Symptoms of a malfunction may vary. First of all, this concerns the quality of the most combustible mixture. Various deposits can aggravate the performance of the oxygen sensor. Also, the element malfunctions due to depressurization of the case.

This often happens due to the obsolescence of the element. Less often, the case is damaged mechanically, since it is located in a fairly safe place. Another reason is the wrong power supply. The sensor contacts can go off, as a result of which the information is received by the control unit incorrectly. The composition of the fuel-air mixture is disturbed (too lean or rich). Another cause of malfunctions is an incorrectly set lead angle. This applies to vehicles with a distributor ignition system. Interruptions can also occur due to problems with high-voltage wires, or due to candles. The motor starts to run at idle and does not work correctly at high speeds.

How to identify the problem?

Consider the possible symptoms of a malfunctioning oxygen sensor:

• Increased fuel consumption.
• Jerks when moving.
• Noticeable drop in power.
• Unstable operation of the engine at idle.
• Increased toxicity of exhaust gases.

Note that these signs do not always happen because of the oxygen sensor.

Therefore, having identified one of the above symptoms, we proceed to a more detailed check of the device. How to do this, we will consider below.

Detailed diagnostics

How to check This can be done in two ways:

• Visually.
• With a multimeter.

Let's look at the first method first. So, first we take out the connector from the lambda probe. We examine all contacts. The wires must not be broken or damaged. If the contacts do not fit tightly together, you need to fix this point. Next, we check the oxygen sensor itself. "Priora", the signs of sensor malfunction of which may consist in the presence of soot, must be urgently repaired.

This is due to the combustion of a rich fuel mixture. Because of this, the device becomes dirty and cannot quickly respond to all changes. In the presence of shiny deposits (this is lead), the oxygen sensor is replaced. Lead damages both the probe itself and the catalyst. What are the signs of a malfunctioning oxygen sensor? The presence of lead indicates the use of excess fuel additives or low-quality engine oil.

Diagnostics with a multimeter

How to check with a multimeter? To do this, we need to connect the signal wire from the block of the oxygen probe to our measuring device. Next, we start the engine and keep the rpm around 2.5 thousand. We release the gas pedal. We pull out the vacuum tube from the fuel regulator and look at the readings of the device.

If the voltage is less than 0.8 V (or not at all), the signs of a malfunction of the oxygen sensor were confirmed. There is no point in repairing it. Due to structural features, the element must only be replaced. The cost of this element is from two to three thousand rubles for VAZ cars. How to change the oxygen sensor yourself, see below.

DIY replacement

First, disconnect the terminal on the battery. Next, we disconnect the block from the sensor itself. Sometimes it is attached with clamps - we also unscrew them. After that, we take in our hands the key "22" or "24" (depending on the car brand) and unscrew the probe. Please note that the sensor is part of the exhaust system and therefore works under extreme loads. It is very difficult to unscrew it the first time. Use VD-40 multipurpose grease. Try not to damage the threads and edges of the stuck sensor itself. As a last resort, you can use a hammer, screwdriver and gas wrench.

Move the element from side to side with light blows. You can pick it up with a screwdriver. If this does not help, drill a hole in the probe in place of the nut with a drill. We insert a screwdriver inside and try to remove it back. This should help. We twist a new one in place of the old element. Try to keep the part snug against the surface of the exhaust manifold pipe (but do not overtighten the element).

Conclusion

So, we found out the main symptoms of a malfunctioning oxygen sensor. A lambda probe is a very small but important element in a car. Its malfunctions can provoke serious interruptions in the operation of the engine. Therefore, it is so important to diagnose its breakdown in time.

The purpose of the lambda probe (oxygen sensor) is to transmit information about the composition of the working mixture from the exhaust manifold to the ECU. The combustion quality of the fuel-air mixture (FA) directly affects the operation of the engine.

On modern cars with an injection engine, one or more catalysts and two or more oxygen sensors are installed. Where is the lambda probe located? Depends on the type of car. Systems with two devices, which are located before and after the catalyst, are common. Thus, the excess of oxygen in the mixture is determined before the gases enter the device. On vehicles with one probe, it is installed at the front, on the exhaust manifold.

How an oxygen sensor works

The ECU measures the amount of fuel supplied using the injectors, setting the volume at a certain moment. The probe provides feedback to accurately determine the proportions of petrol, diesel or gas. The ECU requests information once every 0.5 seconds at idle speed. At higher speeds, the frequency of requests increases proportionally. Analyzing the data, the control unit adjusts the composition of the fuel assembly, making it poorer or richer. Maintaining optimal fuel assembly - the appointment of lambda probes. The ideal air to fuel ratio is considered to be 14.7: 1 (petrol), 15.5: 1 (gas) and 14.6: 1 (diesel).

• Point-to-point, narrowband (simple). Works based on measuring the amount of oxygen in the exhaust gas. The poorer the fuel assembly, the lower the voltage, the richer - the higher.

The average life span of oxygen sensors on Russian gasoline is 40,000-100,000 km. To increase the service life, it is recommended to fill in high-quality fuel with a low content of impurities and heavy metals. It is quite difficult to determine the malfunction by self-diagnosis, it is almost impossible to establish the cause. This can be wear, poor quality gasoline, mechanical damage and other factors.

• Short circuit in the wiring;
• Ignition misfires;
• Natural wear and tear. In conditions of low-quality fuel, the average sensor service life is 40-70 thousand km.

• Fuel consumption increases. Each motorist monitors the fullness of the tank, tries to find his own cruising speed when the fuel consumption is minimal. Therefore, the increased fuel consumption will be noticed immediately. Depending on the severity of the lambda probe malfunction, it grows by 1-4 liters. The increased consumption, of course, can cause not only a faulty oxygen sensor.

How to check a lambda probe

The procedure is as follows:

1. Test the probe signal with a motor tester, dial voltmeter or oscilloscope. Connect a tester between the ground wire and the signal wire, raise the speed to 3,000 Nm, note the time and follow the readings. They should vary from 0.1 to 0.9 volts. We recommend replacing the sensor if the range of changes is less than or in 10 seconds less than 9-10 readings have changed. The cause of the error may be "fatigue" and slow response of the system.

Video instruction:

The purpose of the lambda probe (oxygen sensor) is to transmit information about the composition of the working mixture from the exhaust manifold to the ECU. The combustion quality of the fuel-air mixture (FA) directly affects the operation of the engine.

Correct operation of the oxygen sensor helps:

• Increase the performance of the engine by determining the proportion of injected fuel and air close to the ideal.
• Reduce the production of harmful gases (CO, CH, NOx) emitted into the atmosphere and improve the economical operation of the car due to the correct composition of the working mixture.

On modern cars with an injection engine, one or more catalysts and two or more oxygen sensors are installed. Where is the lambda probe located? Depends on the type of car. Systems with two devices, which are located before and after the catalyst, are common. Thus, the excess oxygen in the mixture is determined before the gases enter the device. In vehicles with one probe, it is installed at the front, on the exhaust manifold.

How an oxygen sensor works

The ECU measures the amount of fuel supplied using the injectors, setting the volume at a certain moment. The probe provides feedback to accurately determine the proportions of petrol, diesel or gas. The ECU requests information once every 0.5 seconds at idle speed. At higher speeds, the frequency of requests increases proportionally. Analyzing the data, the control unit adjusts the composition of the fuel assembly, making it poorer or richer. Maintaining optimal fuel assembly - the appointment of lambda probes. The ideal air to fuel ratio is 14.7: 1 (petrol), 15.5: 1 (gas) and 14.6: 1 (diesel).

Types of oxygen sensors by design and principle of operation:

• Point-to-point, narrowband (simple). Works based on measuring the amount of oxygen in the exhaust gas. The poorer the fuel assembly, the lower the voltage, the richer - the higher.
• Broadband. Generates a signal of a wider range for an accurate estimate of the proportion in fuel assemblies.

The average lifespan of oxygen sensors on Russian gasoline is 40,000–100,000 km. To increase the service life, it is recommended to fill in high-quality fuel with a low content of impurities and heavy metals. It is quite difficult to determine the malfunction by self-diagnosis, it is almost impossible to establish the cause. This can be wear, poor quality gasoline, mechanical damage and other factors.

If you have any suspicions about a malfunction of the oxygen sensor, contact a professional diagnostician. Using the oscillogram, the specialist will determine the causes of the malfunction and suggest remedies.

What causes the lambda probe to fail

• Mechanical damage. Severe impact as a result of an accident, collision with a curb or off-road driving adversely affects the condition of the probe;
• Incorrect engine operation and malfunctions of the ignition system lead to overheating of the oxygen sensor and breakdown;
• Clogged system. The main reason for the malfunction of the lambda probe will be the combustion products of low-quality fuel. The more heavy metals, the sooner it clogs;
• Breakage in the piston group. Defective piston, gudgeon pin and connecting rod leak oil into the exhaust system, which clogs the probe;
• Liquid ingress. Contamination of any kind will shorten the life of the probe;
• Short circuit in the wiring;
• Too rich or poor air-fuel mixture;
• Depressurization of the exhaust system allows air and exhaust gases to pass through, which disables the lambda probe;
• Ignition misfires;
• Fuel additives and "improvers";
• Natural wear and tear. In conditions of low-quality fuel, the average sensor service life is 40–70 thousand km.

Failure of the lambda probe occurs gradually. The consequences of a faulty oxygen sensor result in an emergency engine control mode. So manufacturers protect the car from serious breakdowns, and the driver from emergencies.

Symptoms of a malfunction of the lambda probe

• The level of toxicity of gases increases. To determine toxicity, you can use diagnostics. Outwardly, it is not diagnosed in any way, even the smell of the exhaust will practically not change.
• Fuel consumption increases. Each motorist monitors the fullness of the tank, tries to find his own cruising speed when the fuel consumption is minimal. Therefore, the increased fuel consumption will be noticed immediately. Depending on the severity of the lambda probe malfunction, it grows by 1–4 liters. The increased consumption, of course, can cause not only a faulty oxygen sensor.
• Oxygen sensor errors are issued (P0131, P0135, P0141 and others), "Check Engine" lights up. Usually, a check appears when the probes or catalyst are faulty. Diagnostics will establish the exact cause.
• The catalyst is overheating. Defective lambda probes give incorrect signals to the ECU, which can lead to incorrect operation of the catalyst, its overheating up to a red-hot state, and subsequent failure.
• Twitching and uncharacteristic pops appear in the engine. Lambda probes stop generating the correct signal, which destabilizes idle speed. The revs fluctuate over a wide range, which leads to a deterioration in the quality of the fuel mixture.
• The dynamic characteristics of the car deteriorate, power and traction are lost. Similar signs appear in advanced situations. Defective sensors also stop working on a cold engine, and the machine signals a system problem in various ways.

If you are concerned about one of these signs, see a specialist. With the help of diagnostic equipment, he will determine the exact area of ​​the breakdown and help in fixing it.

How to check a lambda probe

So, the car is jerking, fuel consumption has increased, "Check Engine" is on. Signs are not characteristic only of lambda breakdowns, therefore, a complete system diagnosis is needed. But if you are sure that this is the case, we will tell you how to check the sensor with your own hands.

The procedure is as follows:

1. Warm up the engine to operating temperature. An unheated lambda probe will not work.
2. Remove and inspect the probe and wiring for mechanical damage and contamination. If it is bent, scratched, or covered with soot build-up, lead deposits, white or gray carbon deposits, replace.
3. Check the operation of the lambda probe with an ohmmeter. Often the cause of the malfunction lies in the breakdown of the heating coil or wires to it. How to "ring" him? Connect an ohmmeter between the heater wires, previously disconnected from the block. With proper operation, the resistance of the signal circuit on different vehicles varies from 2 to 10 ohms and from 1 kΩ to 10 mΩ in the heating circuit. If it is not there at all, there is an open circuit in the wiring.
4. Test the probe signal with a motor tester, dial voltmeter or oscilloscope. Connect a tester between the ground wire and the signal wire, raise the speed to 3,000 Nm, note the time and follow the readings. They should vary from 0.1 to 0.9 volts. We recommend replacing the sensor if the range of changes is less or less than 9-10 readings changed in 10 seconds. The cause of the error may be "fatigue" and slow response of the system.
5. Check the health of the lambda probe through the reference voltage. Start the car, measure the voltage between ground and signal wire. If the readings differ from 0.45 volts by more than 0.2, the sensor or circuits in the circuit leading to it are faulty.

If there are no devices for testing the performance of the lambda probe, contact a specialist. They will carry out a full diagnosis and will accurately name the cause of the malfunction for less money and time that you would spend on buying devices and troubleshooting yourself.

Video instruction:

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