Home Lighting Lambda probe: causes of malfunction. Lambda probe, its malfunctions and methods of checking If the oxygen sensor does not work what can

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Lambda probe: causes of malfunction. Lambda probe, its malfunctions and methods of checking If the oxygen sensor does not work what can

Unfortunately, not all car owners know what a lambda probe is and what it is needed for. A lambda probe is an oxygen sensor that allows the electronic system to monitor and balance the correct ratio of air to gasoline in the combustion chambers. It is able to timely correct the structure of the fuel mixture and prevent the destabilization of the engine's working process.

This rather fragile device is located in a very aggressive environment, so its operation must be constantly monitored, since if it breaks down, further use of the car is impossible. Periodic checking of the lambda probe will guarantee the stable operation of the vehicle.

The principle of operation of the lambda probe

The main task of the lambda probe is to determine the chemical composition of exhaust gases and the level of oxygen molecules in them. This figure should range from 0.1 to 0.3 percent. Uncontrolled excess of this standard value can lead to unpleasant consequences.

With the standard assembly of the car, the lambda probe is mounted in the exhaust manifold in the area of the connection of the pipes, however, sometimes there are other variations of its installation. In principle, a different arrangement does not affect the performance of this instrument.

Today, you can find several variations of the lambda probe: with a two-channel layout and a broadband type. The first type is most often found on old cars produced in the 80s, as well as on new economy class models. The wideband type sensor is inherent in modern cars of the middle and upper class. Such a sensor is able not only to accurately determine the deviation from the norm of a certain element, but also to balance the correct ratio in a timely manner.

Thanks to the diligent work of such sensors, the service life of the car is significantly increased, fuel consumption is reduced and the stability of maintaining idle speed is increased.

From the electrotechnical point of view, it is worth noting that the oxygen sensor is not able to create a uniform signal, since this is prevented by its location in the collector zone, because in the process of reaching the exhaust gases of the device, a certain number of operating cycles can pass. Thus, we can say that the lambda probe rather reacts to the destabilization of the engine, which it actually subsequently notifies the central unit and takes appropriate measures.

The main symptoms of a lambda probe malfunction

The main symptom of a malfunction of the lambda probe is a change in the operation of the engine, since after its breakdown, the quality of the supplied fuel mixture into the combustion chamber significantly deteriorates. The fuel mixture, in fact, remains uncontrolled, which is unacceptable.

The reason for the exit from the operating state of the lambda probe may be the following:

depressurization of the case;
penetration of outside air and exhaust gases;
overheating of the sensor due to poor-quality painting of the engine or improper operation of the ignition system;
obsolescence;
incorrect or intermittent power supply that leads to the main control unit;
mechanical damage due to improper operation of the car.

In all of the above cases, except for the last, failure occurs gradually. Therefore, those car owners who do not know how to check the lambda probe and where it is generally located, most likely, will not immediately notice the malfunction. However, for experienced drivers, it will not be difficult to determine the reason for the change in engine operation.

The gradual failure of the lambda probe can be divided into several stages. At the initial stage, the sensor ceases to function normally, that is, at certain operating moments of the motor, the device stops generating a signal, after which the idle speed is destabilized.

In other words, they begin to fluctuate in a rather wider range, which ultimately leads to a loss in the quality of the fuel mixture. At the same time, the car begins to twitch for no reason, you can also hear uncharacteristic claps of the engine and the warning light on the instrument panel must light up. All these abnormal phenomena signal the car owner about the incorrect operation of the lambda probe.

At the second stage, the sensor stops working at all on an unheated engine, while the car will signal the problem to the driver in all possible ways. In particular, there will be a noticeable drop in power, slower response when the accelerator pedal is applied and all the same pops from under the hood, as well as unjustified jerking of the car. However, the most significant and extremely dangerous signal of a lambda probe breakdown is engine overheating.

If all previous signals are completely ignored, indicating a deterioration in the state of the lambda probe, its breakdown is inevitable, which will cause a large number of problems. First of all, the possibility of natural movement will suffer, fuel consumption will also significantly increase and an unpleasant pungent odor with a pronounced shade of toxicity from the exhaust pipe will appear. In modern automated vehicles, in the event of a breakdown of the oxygen sensor, emergency blocking can simply be activated, as a result of which the subsequent movement of the car becomes impossible. In such cases, only an emergency call for a tow truck can help.

However, the worst case scenario is depressurization of the sensor, since in this case the car's movement becomes impossible due to the high probability of engine breakdown and subsequent expensive repairs. During depressurization, the exhaust gases, instead of exiting through the exhaust pipe, enter the intake channel of the atmospheric reference air. During engine braking, the lambda probe begins to record an excess of oxygen molecules and urgently gives a large number of negative signals, which completely disables the injection control system.

The main sign of sensor depressurization is loss of power, especially during high-speed movement, characteristic tapping from under the hood while driving, which is accompanied by unpleasant jerks and an unpleasant odor that is emitted from the exhaust. Also, the depressurization is evidenced by the visible sediment of soot formations on the body of the exhaust valves and in the area of \ u200b \ u200bthe candles.

How to determine a malfunction of a lambda probe is described in the video:

Electronic check of lambda probe

You can find out about the state of the lambda probe by checking it on professional equipment. For this, an electronic oscilloscope is used. Some experts determine the performance of the oxygen sensor using a multimeter, however, it can only state or deny the fact of its breakdown.

The device is checked during the full operation of the engine, since at rest the sensor will not be able to fully convey the picture of its performance. In the event of even a slight deviation from the norm, it is recommended to replace the lambda probe.

Replacing the lambda probe

In most cases, a part such as a lambda probe cannot be repaired, as evidenced by statements about the impossibility of repairing from many automotive manufacturers. However, the overestimated cost of such a unit from official dealers discourages any desire to purchase it. The optimal way out of this situation can be a universal sensor, which is much cheaper than its native counterpart and is suitable for almost all car brands. Also, as an alternative, you can purchase a sensor that was in use, but with the duration of the warranty period, or a completely exhaust manifold with a lambda probe installed in it.

However, there are cases when the lambda probe functions with a certain error due to severe pollution as a result of the settling of combustion products on it. In order to make sure that this is indeed the case, the sensor must be checked by specialists. After the lambda probe has been checked and the fact of its full operability has been confirmed, it must be removed, cleaned and installed back.

In order to dismantle the oxygen level sensor, it is necessary to warm up its surface to 50 degrees. After removal, the protective cap is removed from it and only after that you can start cleaning. Phosphoric acid is recommended as a highly effective cleaning agent, which easily removes even the most stubborn combustible deposits. At the end of the soaking procedure, the lambda probe is rinsed in clean water, thoroughly dried and installed in place. At the same time, do not forget about lubricating the threads with a special sealant, which ensures complete tightness.

It is very difficult, therefore it needs constant support of its efficiency and timely preventive maintenance. Therefore, in case of suspicion of a malfunction of the lambda probe, it is necessary to immediately diagnose its operability and, if the fact of failure is confirmed, replace the lambda probe. Thus, all the most important functions of the vehicle will be maintained at the same level, which will guarantee the absence of further problems with the engine and other important elements of the vehicle.

It is considered to be more economical and much more environmentally friendly. Moreover, the power supply system of such an internal combustion engine has a large number of sensors.

The lambda sensor (oxygen sensor) is an important element of the power supply system for injection engines. Moreover, this sensor does not have a long service life for a number of reasons.

In the event of a failure of the lambda probe, the engine may be unstable, lose power, etc. Next, we will consider what a lambda sensor is in a car, the main purpose of a lambda in a car, what signs indicate problems with this element, and also how to check an oxygen sensor

Read in this article

Oxygen sensor in a car: purpose and principle of operation

The main task of the engine sensors is to transmit to signals, many of which allow the control unit to flexibly adjust the fuel-air mixture, taking into account the constantly changing operating modes and loads on the internal combustion engine.

In turn, among it is difficult to overestimate the significance of the lambda probe (sometimes motorists on the forums mistakenly call this element a lambda probe or lambda probe). Simply put, oxygen sensors in a car measure the excess air ratio in the air-fuel mixture.

The general structure of the lambda probe is as follows:

metal case;
ceramic insulator;
sealing ring;
wiring and cuffs for sealing;
protective case with a hole for ventilation);
conductive contact;
ceramic tip;
spiral in the tank;
protective shield with a hole for gas outlet.

For the production of sensors of this type, heat-resistant materials are needed, since the device operates at high temperatures. In total, oxygen sensors are divided into several types, depending on the number of wires per sensor.

In fact, this sensor detects the excess air ratio by sniffing out the exhaust and recording the residual oxygen in the exhaust gases. The main task of the oxygen sensor is to transmit important information to the engine ECU, which allows the controller to determine how efficiently the fuel combustion process in the cylinders is occurring.

This information is needed in order to maintain optimal conditions for the operation of the catalyst (catalytic converter), which filters the vehicle exhaust and reduces the amount of harmful emissions into the atmosphere.

The main reason for this control is that the most efficient catalyst operation is possible only when 14.6–14.8 parts of air and 1 part of fuel are burned in the engine. When such a mixture is burning, the lambda will be equal to 1 ± 0.01.

It is quite obvious that in order to constantly prepare such a mixture in different modes, a developed power system with electronic fuel injection is needed, which constantly receives signals from sensors (including from an oxygen sensor).

At the same time, the lambdasonde itself is in the exhaust system, operates in high heating conditions, and can also fail if there are malfunctions in the engine. Let's look at the signs and causes of lambda breakdowns.

Lambda Sensor: Symptoms of Malfunctions

As a rule, the oxygen sensor (lambda probe) can fail or work intermittently if the engine itself is worn out or defective.

For example, if not working properly, engine oil enters the cylinders and then into the exhaust. It can also get into the cylinders, etc. All this leads to the fact that the resource of the sensor is reduced or the element stops working.

Problems with mixture formation or ignition, overheating, short circuits and wiring faults, sensor contamination (including after the combustion of gasoline with a high content of octane additives) can also disable the lambda.

One way or another, in the case of a faulty lambda probe, the CO content in the exhaust gases increases from 0.1–0.3% to 4–6% or more. In this case, usually:

the engine loses power;
the motor twitches, the revolutions float;
fuel consumption increases;
a check is lit on the dashboard;
The internal combustion engine may be unstable, in emergency mode, etc.

By the way, on some cars there can be only one such sensor, while on others there is a second lambda probe, and there may be more sensors. In the first case, the lambda can often be disabled programmatically.

On cars with two lambda probes, especially if the second oxygen sensor fails, it is much more difficult to solve the problem. The fact is that you will need to actively intervene in the operation of electronic systems, reflash the computer, install the so-called lambda probe trickery, etc.

How to check the lambda, repair or replace the oxygen sensor

The most effective way to check is computer engine diagnostics, which allows you to determine errors by the lambda probe. Decoding errors in computer diagnostics of the engine allows you to localize the problem.
It is also possible to install a known working sensor on the vehicle. Then you need to reset the errors. If the engine's operation returns to normal, then the reason is precisely in the oxygen sensor.
The performance of the lambda probe can also be assessed visually. This visual check will not be accurate, but it is sometimes effective. To begin with, the wire connectors are inspected. Everything must be in place and securely fastened.

Then you can unscrew and inspect the oxygen sensor. If soot is visible (most often as a result of problems with the lambda probe heater or after the combustion of a rich mixture), the contaminated sensor loses its ability to normally assess the composition of the exhaust.

Also, a problem will be indicated by the presence of shiny gray deposits, which indicate an excess of lead in the fuel. Typically, lead will damage the sensor and often the catalyst. If there are visible whitish deposits, this is also a bad indicator. In this case, lambda can be "killed" by additives in fuel or engine oil.

Another way to check is to ring the lambda with a voltmeter tester. To quickly check the lambda probe, the tester is switched to the DC voltage measurement mode. The car is started by disconnecting the oxygen sensor from the block before starting. Next, its signal wire is connected to a voltmeter.

Then you need to raise the engine speed to 2.5 thousand rpm and release the gas pedal. Then you need to remove the vacuum pipe from the fuel pressure regulator. After that, you can evaluate the testimony of the tester. If the diagnostics and check of the lambda probe shows 0.8V or less, and there are no readings at all, then it is clear that the lambda probe is faulty.

Also, the check must be repeated, creating a lean mixture. To do this, you need to suck in air through a vacuum tube. If the oxygen sensor is good, then the voltmeter reading will be 0.2 V or less.

In the case when all checks showed that the sensor is faulty, then the lambda probe needs to be replaced. Also, in some cases, cleaning can help, but the method is far from always effective.

How to clean a lambda probe

Immediately, we note that the part is officially non-repairable, that is, the repair of the lambda probe is not expected and the sensor needs to be changed. However, the element often fails precisely because of carbon deposits on the sensitive element. This element is located under the protective cap.

It is quite obvious that if the carbon deposits are removed, there is a chance that the sensor will work. As a rule, you can try to clean the lambda in phosphoric acid. This acid removes soot and dirt in 20-30 minutes without harming the sensitive electrodes.

The difficulty is that you can effectively clean the oxygen sensor by removing the protective cap. If the outside sink does not help, the cap is removed on a lathe. Further, after cleaning, the cap must be re-fastened. It is usually fixed using argon welding. If such cleaning has not yielded results, the only way out is to replace the lambda sensor.

Replacing the oxygen sensor

To begin with, if the car has a heated oxygen sensor, it can often be replaced with an unheated lambda probe. You can also make a reverse replacement with a heated part. Even if the connectors on the circuit do not match, universal contacts can be used.

As for the replacement itself, you need to change the oxygen sensor only after the engine has cooled down. The replacement of the lambda probe must be carried out after the ignition is turned off. It is optimal to buy a lambda probe that has a marking similar to that of the element installed on the car.

The replacement itself is performed as follows:

first, you need to disconnect the wires from the sensor;
then the lambda probe is unscrewed with a wrench;
after a new element is screwed in and the wiring is connected;
the final stage is checking the performance of the sensor;

Please note that when unscrewing and twisting the lambda probe, it is important not to rip the thread, that is, no extra effort should be made.

As you can see, diagnosing lambda problems involves a separate knowledge of which signs indicate malfunctions in the oxygen sensor, as well as how to check the lambda probe with a voltmeter.

By the way, it is recommended to check the lambda probe every 30-40 thousand km. mileage, especially if there are problems with mixture formation. To check, you need to warm up the engine, then raise the idle speed to 2 thousand rpm. On the voltmeter, the voltage of the lambdazonde should be within the range from 0 to 1 V (taking into account the exhaust temperature of 300-400 degrees Celsius).

Please note that it is during warming up that the zirconium electrode is able to conduct current, and the amount of oxygen in the atmosphere and oxygen in the exhaust leads to the fact that an output voltage appears on the electrodes of the lambda probe. It is for this reason that the lambda probe is checked on a well-heated engine.

We also note that if there is such an opportunity, it is better to use an oscilloscope for testing, rather than a multimeter. It is the first option that allows you to more accurately assess the signal quality. You also need to measure the resistance of the sensor heater. Measurements are first performed with the plug removed, the norm is at a normal temperature of 2-14 ohms.

Then the voltage on the heater is measured (with the ignition on, as well as the connected sensor connector). Normally, the indicator should be at least 10.5 V. In the case when the value is less, the wiring, contacts, etc. are checked.

It should also be noted that in the case when the lambda probe was previously unscrewed and put back, it is recommended to process the thread with a special assembly paste. In this case, do not allow such a paste to get on the protective tube in order to avoid contamination and possible malfunctions of the sensor.

If the device is new, large manufacturers already supply the paste-treated sensors from the factory. The main thing is to observe the recommended tightening torque when installing the lambda probe (as a rule, the indicator is 40, 50 or 60 Nm).

Finally, we note that the lambda probe is a very fragile and sensitive sensor. It must be carefully twisted, not dropped during installation, it is forbidden to knock on the oxygen sensor, it is not allowed to become oily and contaminated, etc.

Since the sensor takes outside air for comparison with the exhaust, and the intake takes place through the connector, such a connector should not be sprayed or lubricated with contact sprays.

Special care should be taken when. The lambda probe connector must be separately and properly insulated. Even when driving off-road, the sensor can be mechanically damaged or dirty. To avoid this, you should take into account the peculiarities and place of its installation on the machine. As a rule, it allows partially protecting the lambda as well.

What is the bottom line

As you can see, the oxygen sensor in a car is an important element on which the quality and composition of the fuel-air mixture directly depends. At the same time, the lambda probe does not have a long service life and can fail for a number of reasons. One way or another, the specified element needs to be checked and replaced if necessary.

As a result, we note that it is strongly not recommended to operate a car with a faulty lambda probe. The fact is that malfunctions of the oxygen sensor can lead to failure of the catalyst, which is a much more expensive element than the oxygen sensor.

The lambda probe is one of the elements of the power supply system for injection vehicles, which in our operating conditions can create problems. How can you avoid them?

Appointment

The Greek lambda in the automotive industry stands for the ratio of excess air in the fuel-air mixture. Hence the name of the sensor, which measures this coefficient, or rather, the residual oxygen (O2) in the exhaust gases (another name is the oxygen sensor). The purpose of the sensor is to provide the engine ECU with information to determine the nature of fuel combustion. This is necessary to create normal operating conditions for the catalytic converter. The fact is that the "window" of the catalyst's effective operation is very narrow, when 14.6-14.8 parts of air and 1 part of fuel burns in the cylinders (with the combustion of such a mixture, lambda = 1 ± 0.01). This precise control of the air-fuel ratio is only possible with electronic fuel injection systems. The lambda probe in these systems acts as a controller in the exhaust tract.

Lambda probe: causes and symptoms of breakdowns

Malfunctions or even failure of the lambda probe can occur due to:

	breaks in electrical connection circuits;
	closures;
	pollution by combustion products of gasoline with a high content of octane-enhancing additives;
	thermal overloads due to ignition interruptions;
	mechanical damage (for example, when driving off-road).

The service life of the lambda probe is greatly reduced by the poor condition of the oil scraper rings, the ingress of antifreeze into the cylinders and exhaust pipes, and an enriched fuel-air mixture.

With a faulty lambda probe, the CO content in the exhaust increases from 0.1-0.3% to 3-7%. It is difficult to reduce its value in most old motors without replacing the sensor, since the power reserve of the potentiometer mixture quality regulator may not be enough. In cars with two lambda probes, in the event of a failure of the second sensor, it is impossible to achieve normal engine operation without serious intervention in the electronics.

Lambda probe: malfunction treatment

There is no technology for repairing faulty lambda probes - in the event of a breakdown, they must be replaced. However, our "Uncle Vasya" still developed a method for restoring these sensors, but it is not effective in all cases. Most often it stops working due to carbon deposits on the sensing element under the protective cap. If the plaque is removed, the “lambda” functionality is restored. You can clean the sensitive element of the sensor by washing it in orthophosphoric acid, which corrodes contamination in 10-20 minutes without destroying the electrodes with rare earth metals. It is more efficient to clean the lambda probe after removing the protective cap on a lathe and washing with a thin brush. But it is advisable to do this if it is possible to fix the cap using argon welding. After rinsing, the sensor should be rinsed with water and dried. If washing does not help, then the "lambda" needs to be changed. The cost of washing is much less than the cost of a new lambda probe (from 300 UAH). You can replace an unheated sensor with a heated one (but not vice versa!). If the connectors are incompatible, lay the missing heating circuit yourself, and use universal automotive contacts instead of the connector.

Why change the lambda probe in time:

Lambda probe: diagnostics

The lambda probe provides an effective measurement of the residual oxygen in the exhaust gases after warming up to a temperature of 300-400 ° C. Only under such conditions does the zirconium electrolyte acquire conductivity, and the difference in the amount of atmospheric oxygen and oxygen in the exhaust pipe leads to the appearance of an output voltage on the electrodes of the lambda probe. Therefore, the lambda probe signal is checked with the engine running and warm. An oscilloscope is better suited for measurement than a multimeter, since it is the most accurate way to estimate the waveform and frequency of the signal.

Then the resistance of the sensor heater is measured (with the plug disconnected), which is at room temperature from 2 to 14 ohms (according to the manufacturer's requirements). Next, the voltage supplied to the heater is checked: with the ignition on and the probe connector connected, it should be at least 10.5 V. If this value is lower, you must carefully check the battery voltage, cables and connections.

Lambda probe: installation details

	The sensors should only be installed and removed using the appropriate tools.
	If the lambda probe is reused, the thread must be treated with a special assembly paste. At the same time, avoid getting the paste on the protective tube, as this can lead to malfunctions of the sensor. New lambda probes from leading manufacturers are pre-treated with paste.
	Observe the tightening torque specified by the manufacturer, usually 40 to 60 Nm.
	Lambda probes must be handled carefully to avoid mechanical damage (for example, due to falling).
	Since the sensors draw in external (reference, for comparison) air through the connector, it must not be sprayed or lubricated with contact spray. When flushing the engine and underbody, the lambda probe connector must be carefully insulated.


Opinion

Yuri Datsyk
Photo Bosch, GM

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The lambda probe is necessary for the normal operation of the system, which ensures the control and correct formation of the air-fuel mixture in the car. It is located in the exhaust manifold, where the pipes are connected. But other accommodation options are not excluded.

Constant loads, exposure to an aggressive environment leads to breakdowns, which are accompanied by malfunctions in the operation of the car. It is easier to avoid problems by periodically checking the oxygen sensor; signs of malfunction can also suggest the need to contact a service.

If there is a malfunction of the oxygen sensor, this affects the performance of the power plant. Breakdowns are always accompanied by a decrease in the quality of the fuel mixture formed.

Common reasons:

mechanical damage appears, depressurization is possible due to incorrect operation, off-road driving;
problems develop, power outages;
thermal overload, overheating resulting from improper operation of the ignition;
severe pollution due to the use of fuel, which contains many additives that increase the octane number;
air, exhaust gases can enter the system.

Typically, the probe breaks down gradually, which allows you to identify the problem in time.

Signs occur alternately:

An unstable idle appears. The reason is that at certain times the signal is not generated. The fluctuations can be severe, over a wide range.
The quality of the air-fuel mixture decreases. This is accompanied by the appearance of jerks, uncharacteristic pops in the operation of the power unit. The dynamics are deteriorating.
The corresponding light on the dashboard comes on, which is a signal to the owner.
If the situation worsens, the device stops working on an unheated motor.
Power drops noticeably, responsiveness when you press the gas. Pops, jerks appear more often. Engine overheating is not excluded.
Fuel consumption is increasing, exhaust gases acquire a toxic odor.

In such a situation, it is necessary to replace the lambda probe; signs of malfunction should not be ignored. On new car models, emergency mode is activated, which makes further movement impossible. This eliminates the development of more serious problems with the motor, costly restoration.

How is the sensor checked?

The service life of the sensor depends on the type of device and starts from 50,000 for unheated, 100,000 for heated and 160,000 km for planar. If the first problems appear, you can check the status of the device.

Visual assessment:

The presence of soot affects the transmission of signals to the control unit. The reason is overheating, high oxygen content in the fuel mixture.
The formation of whitish and grayish deposits signals a large amount of additives in the fuel, which affects the performance of the unit.
Glittering beads suggest that the fuel has increased lead particles.

To determine the efficiency, to obtain accurate information, professionals use special equipment. If it is not possible to go to a car service, it is enough to clarify how to check the lambda probe with a multimeter. It's easy to do it yourself.

Main steps:

The motor is gradually warmed up to 75 degrees.
They monitor the gradual increase in revolutions to 3000, maintaining the indicators for 3 minutes. This is necessary to warm up the sensor.
Taking a multimeter, the signal wire is connected to the test device. The second wire is fixed to ground. During normal operation of the sensor, the readings given by the multimeter remain in the range of 0.2 - 1 Volt.
During testing, the data should constantly change - when you press the gas pedal, it should approach 1 Volt, and when released, it quickly fall.

Thinking about how to check the lambda probe, it is taken into account that if the instrument readings do not change during the process, a voltage of 0.5 volts remains during gas firing, the unit is probably faulty. If the data is zero, you need to make sure that the sensor is connected to ground. It is recommended to check the integrity, serviceability of the wiring leading to the ignition switch, relay.

Advantages of contacting a car service

In a car service, diagnostics are carried out using an electronic oscilloscope. It is advisable to do this after 30,000 km of run, which will avoid unforeseen breakdowns. To check the oxygen sensor lambda probe, experts observe several important points.

Car service check:

The sensor is heated to 300 - 400 degrees for normal operation and measurement of residual oxygen.
So, the electrolyte in the design of the device receives conductivity, and the differences in the amount of atmospheric and oxygen in the exhaust determine the appearance of the output voltage.
By disconnecting the plug, determine the resistance of the heater. The indicator should remain within 2 - 14 ohms.
The voltage supplied to the heater is estimated. The best option is 10.5 ohms. The check is performed with the ignition on with the probe connector connected.

The advantage of referring to the wizards lies in the accuracy of determining not only the health, but also the state of the element.

Is it possible to clean the probe

If the oxygen sensor breaks down, you cannot do without replacing it, since there are no methods for its recovery. Given the high cost of a spare part, repairs can be expensive.

But there are other options:

select a universal sensor, which is much cheaper than the original, suitable for most car models;
they are looking for a used part with a guarantee, an exhaust manifold with an installed sensor is also suitable.

But it is not always necessary to change a part. It is enough to know how to clean the lambda probe. After all, situations of heavy pollution are not excluded. Particles of soot and carbon deposits can be deposited on the sensitive element covered with a protective cap. Because of this, malfunctions and errors appear in the work. After removing the plaque, the effectiveness of the device is restored.

Subtleties of cleaning:

The procedure begins with dismantling, for which the surface of the part is heated to 50 degrees. Withdrawing the sensor, remove the protective cap.
The work uses orthophosphoric acid, which is able to remove particles of carbon deposits, impurities, without damaging the electrodes, important elements. Soaking is carried out for 10 - 20 minutes.
A more difficult option involves removing the protective cap and washing using the finest brush. After removing impurities, the part is washed and dried.

Washing is carried out if it is possible to reattach the protection, which involves carrying out argon welding. The cost of cleaning is much less than replacement. This solution is only suitable for serviceable but dirty sensors. When reattaching it, it is important to lubricate the threaded joint with assembly paste. When installing a new element, no lubrication is required, the connection is processed during production.

To understand what the lambda probe is responsible for, you should pay attention to the operation of the fuel system. The oxygen sensor is an important element to maximize engine efficiency on injection machines.

High performance is possible with complete combustion of the air-fuel mixture. Therefore, it is important to determine the optimal proportion of the constituents. Due to the correct assessment of the oxygen content in the exhaust, a subsequent calculation of the fuel mixture is carried out.

A properly working probe provides:

reduction of fuel consumption by up to 15%;
improving the environmental friendliness of exhaust gases;
the factory resource of the catalyst is preserved;
excellent dynamics, responsiveness during control are maintained.

The best performance is characteristic of cars with two sensors, where one is located before the catalyst, and the second after it.

When studying the principle of operation of a lambda probe, it is worth considering that the scheme of action differs depending on the type.

Types of devices:

Two-point models in their design include two electrodes. This makes it possible to estimate the coefficient of excess oxygen in the fuel mixture by determining its content in the exhaust. The action takes place during the passage of the exhaust gases. Here, the first element is sensitive to oxygen. The second is made of zirconium. At the moment the exhaust passes, the potential is measured between the electrodes. An increase in the indicator means an excess of oxygen.
Broadband probes represent a new type of probe. A voltage of 450 mV is maintained here. The device includes ceramic components - two-point and injection. The latter draws in the oxygen present in the exhaust. In this case, a certain current strength is used. A drop in the oxygen level leads to an increase in voltage, which is accompanied by a corresponding signal from the ECU.

Care, timely diagnostics, troubleshooting allows you to exclude most unforeseen situations, to preserve the factory resource, the functionality of the units.

Lambda - what is it? In this case, we are not talking about the letter of the Latin alphabet. When signs of increased fuel consumption, black exhaust gases and unstable engine operation appear, one of the most common causes is a breakdown of the lambda probe. What is a lambda probe in a car and what a lambda probe is for, you will learn from this article.

This is a special oxygen sensor that is responsible for the correct proportions of air volumes in the fuel system. In other words, a lambda probe is a regulator that collects and transmits information to prepare an optimal fuel mixture.

But when this part performs its duties stably and debugged, the car saves fuel, catalysts that reduce emissions of harmful substances into the atmosphere last longer. Therefore, every motorist should know and remember about the principles of its operation and diagnostics.

WATCH THE VIDEO

How an oxygen sensor works

So, the oxygen measurement in the fuel system takes place in the exhaust manifold. A sensor is necessarily located here, which determines the oxygen volumes. A second lambda probe can be located at the outlet of the catalytic converter for additional accuracy in measuring the oxygen level.

To understand the mechanism of functioning of the lambda probe, consider the algorithm of its operation.

The principle of operation of a two-point lambda probe depends on the electrodes. The oxygen level affects their tension. If the voltage level indicates an excess of oxygen, then the information is formed one, with a lack of oxygen another.

The broadband lambda probe is a more complex two-piece design. This sensor has a constant voltage across the electrodes, which becomes less or more depending on the oxygen content.

The results of the fuel check in each case are transmitted to other vehicle systems to form the optimal mixture for further injection.

Work illustration

For what reasons can the sensor's performance be impaired?

What is a lambda probe? Is a complex mechanical device that is prone to breakage. They arise for the following reasons.

A poor-quality or very old device case may lose its tightness. As a result, gases, dirt, air penetrate inside, which make correct operation impossible.

Although the probe operates at high temperatures, it may also be susceptible to excessive heat build-up. Most often this happens when the factory power of the motor is increased by technical enthusiasts.

There is a fixed warranty period for work. After passing through it, the probe may lose its properties.

The use of low-quality diesel or gasoline, as well as leaded fuel, ruins the working surface of the sensor and also leads to its failure.

One of the most pressing reasons for our country. Driving on poor roads can damage the sensor's internal components. Further operation becomes impossible.

Appearance

How to identify a faulty sensor

Consider the main symptoms of a lambda probe malfunction.

Symptoms of a malfunction of the lambda probe most often declare themselves by the unstable functioning of the internal combustion engine. The turnover is very "walking". Even when idling in warm weather, they can increase sharply for no explainable reason.

The need to refuel more often than usual and the average fuel consumption is higher than the established norm are some of the most accurate indicators.

At the same time, if a car enthusiast, depressing the accelerator pedal to the end, feels that the car accelerates significantly worse, there is a high probability that the sensor is faulty.

Well, the most common - the appearance of the light of the "Check inzhin" indicator may also be due to a malfunction of the oxygen regulator. At the technical station, they will definitely establish the exact reason. Or you can check everything yourself. We will indicate how to do this further.

Other signs of a malfunction of the oxygen sensor will always be associated with a malfunction of the engine.

Appearance of a faulty device

How to check the health of lambda probes with one wire, two, three and 4 wires yourself: with a multimeter, with your own hands, a tester, etc.

What is a lambda probe on a car and what a lambda probe is for, we found out in the first part of the article.

Now we will consider how to diagnose his condition. You need to get the sensor. Any auto locksmith can show the oxygen sensor, but an ordinary car enthusiast will have to look at the manufacturer's instructions to find it. In any case, it can most often be accessed by simply opening the hood.

Sometimes a visual inspection is enough to immediately identify a malfunction. Visual inspection is necessary to exclude mechanical deformation and the ingress of foreign substances. If the device is damaged, it will be immediately noticeable. Replacement will also be required if the sensor is coated with soot or gray coating - these are signs of damage to the sensor due to refueling with low-quality fuel.

The second method also does not require the use of any device. It is enough to rearrange the sensor to another, the same car. If the malfunctions persist, then the problem is in him.

To check with a multimeter, you need to start the car for 10-20 minutes, then turn it off. Disconnect the oxygen regulator and connect it to the multimeter. Then start the engine and squeeze out the gas up to 3000 rpm. The procedure is best done together. One presses on the gas, and the second looks at the readings - they should be at 0.9 watts. Any value less than this indicates a malfunction.

Using a 4-wire tester to measure is also not difficult. For its implementation, the negative wire of the tester is connected to the motor, and the positive wire to the signal wire of the probe. It is worth briefly mentioning that there can be up to 4 probe wires. There are no problems with one wire - it is always a signal wire. But if there are more of them, you cannot do without the help of instructions. So, when the tester is connected, you need to turn on the motor to run for 10 minutes. After warming up to a sufficient temperature, the sensor should turn on. The voltage will change for some time and be different values, approximately 0.3 - 1 volt. However, it then stabilizes at 0.45 W. If the stable voltage figure is different, the sensor will have to be changed.

How much does a lambda probe cost and how much will a motorist's wallet empty if this device malfunctions? For domestic cars, the price will not exceed 2-3 thousand rubles. But foreign cars will have to fork out. The cost of probes can range from 4 to 10 thousand rubles.

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Many people have a question - why such a simple design, even on domestic machines, costs several thousand.

The answer lies in the composition of the elements from which the probe is made. There are quite a few valuable and in some cases precious metals among them.

It is also necessary to diagnose and replace this important device in a timely manner.

Checking with a multimeter