One of the important elements of the engine exhaust system is the oxygen sensor or lambda probe. Failure of this device can cause serious vehicle malfunctions, so the driver should always take care of regulator diagnostics. From this material, you will learn what signs of a malfunction in the lambda probe, for what reasons the regulator breaks down and how to replace it.

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Why can an oxygen sensor fail?

Before proceeding with the diagnosis of signs and symptoms, as well as repairing one or another malfunction with your own hands, we suggest that you familiarize yourself with the reasons for the failure of the regulator.

So why the regulator doesn't work:

1. Use of low quality fuel. If the fuel contains iron, water, decay elements, lead and other harmful substances, it will damage the regulator. Such components clog platinum electrodes fast enough to clog them, it will take two or three refueling with low-quality fuel.
2. Heating malfunction. The oxygen sensor is equipped with a special heating. If the heating fails, the regulator may give an error about operation. Heating is an important element because it is through heating that the driver receives precise information from the lambda probe. If the regulator is running unheated, it will produce the wrong amount of oxygen in the exhaust. Accordingly, the heating comes into operation immediately after starting the engine. A breakdown of the heating implies the repair and replacement of the sensor as a whole, since in the absence of heating there will be no sense from the regulator.
3. Overheating of the lambda probe housing as a result of the fact that the ignition timing was incorrectly set. Also, a symptom of overheating may appear as a result of a too rich combustible mixture.
4. If the condition of the oil scraper rings is poor, Doing so may cause engine fluid to enter the exhaust pipe. Accordingly, its effect on the sensor can be destructive and it will be necessary to repair or replace the device.
5. Malfunctions of the ignition system are another reason why lambda doesn't work. We are talking about candles, coils, all kinds of modules and wiring. The cause may be pops in the exhaust pipe - they can destroy the fragile ceramic of the device.
6. Shocks appear in the intake manifold of the motor.
7. Incorrect start of the car engine. The need to repair a malfunction arises as a result of multiple and at the same time unsuccessful attempts to start the car's engine, and also from the fact that these attempts are carried out in short intervals. As a result, unburned fuel accumulates in the engine exhaust manifold. When a shock wave occurs, the fuel can ignite.
8. Contact with the ceramic element of various consumables - solvents, coolants, detergents, etc., may necessitate regulator repair.
9. Application of sealants when installing the regulator can lead to serious problems. Especially if at room temperature they can cure or contain silicone in their composition.
10. As a result of an open or poor contact of the device, as well as when the output wiring is shorted to ground there is a need for repair.
11. If the motor runs with incorrectly adjusted valves, which can be drawn in or pinched, or with valves that have not been regulated for a long time.
12. Incorrect compression level in the engine cylinders. If the compression is uneven, then this can lead to unbalanced combustion of the combustible mixture.
13. When installing the timing belt, the device marks were incorrectly set, or they could be violated during the operation of the vehicle.
14. Clogged petrol injectors of the engine. Also, the need to repair a malfunction occurs as a result of clogging of the gasoline injectors of the engine or due to the fact that an imbalance has arisen in their work.

The main symptoms of malfunctions

Next, we will consider the signs that will make it possible to diagnose and check whether the lambda probe corrector and the sensor as a whole are working or not. As practice shows, the device fails gradually, and not immediately. Therefore, if you do not know where the lambda probe is installed and how to check it, then most likely you will not immediately detect signs of breakdown. But if you familiarize yourself with the signs described below, then you will not have problems during the check.

So, the failure of the regulator can be roughly divided into several stages.

1. The first sign is that the device stops working normally. In particular, during certain operating moments of the engine, the regulator refuses to generate a signal. As a result, the adjustment of idle speed begins to destabilize, that is, the speed floats. This symptom may indicate the need to restore the device. It should be noted that the revolutions can float in a very wide range, respectively, over time this can lead to a decrease and loss of the quality of the combustible mixture.
2. Another sign that indicates the need to restore the device is that the machine begins to twitch. As a result of starting and checking the motor, you may hear pops uncharacteristic for its operation. In addition, if during the check you noticed that a new indicator light up on the dashboard, then this indicates that the device needs to be checked in more detail using a multimeter. If you do not have a multimeter, contact an electrician for help.
3. The next step, by which you can check the malfunction, is a complete failure of the regulator when running on a cold engine. In this case, the control unit will warn the driver about a malfunction and the need for repair - the engine power will decrease, when you press the gas pedal, a slower reaction of the car will be felt. The same pops will be heard from under the hood, the car will twitch when driving - these signs of malfunction indicate that it is necessary to repair and restore the device.
4. One of the most dangerous signs of a problem is motor overheating.
5. Also, increased fuel consumption may indicate the need for repair and restoration, and an unpleasant odor may appear from the car's muffler with a sign of toxicity.
6. If you have a modern car, then as a result of the breakdown of the device, the emergency locking system may work. Accordingly, further movement in the vehicle will be impossible, the only way out is to call a tow truck and take the car for repair.
7. One of the worst options for the further development of events may be the depressurization of the device, since when depressurizing, driving a car will be impossible. There is a high probability of engine failure. When this process occurs, the exhaust gases do not exit through the muffler, but enter the intake duct. When the driver applies the brake, the sensor sees an excess of oxygen in the system, as a result of which it emits a huge number of negative pulses. Thus, the injection control system can completely fail. If the regulator is depressurized, this can be recognized as a result of power loss, which is especially felt when driving fast. Jerks and pops, as well as an unpleasant smell are the same symptoms of breakage. You can also check the body of the exhaust valves and the place where the plugs are installed - they can form a sediment from soot (video by HondaDiagnostic Sistem).

How to check a lambda probe yourself?

To check the sensor yourself, you need a voltmeter. It can be digital or pointer, no difference.

So, the check is carried out in several stages:

1. First you need to turn on the ignition, but it is not recommended to turn off the lambda probe. Otherwise, the engine control unit may record an error in memory indicating the failure of the lambda probe heater.
2. With the probes of the device, it is necessary to pierce the wires that fit the heater. Alternatively, you can plug the test leads into the connector on the side of these wires.
3. Look at the voltmeter screen - it should show a voltage level equal to the voltage in the battery. Remember that when the engines are off, minus from the computer may not be supplied. Accordingly, after this, you must carefully start the engine.

The positive wire comes to the heater device, as a rule, directly, while the circuit can be protected by a fuse. As for the negative wire, it comes from the motor control unit. So if there is no plus, then it is necessary to check the electrical circuit from the battery through the fuse to the sensor.

It is possible that another relay is installed on this section of the circuit. In the event that there is no minus, then it is necessary to check the wiring that goes to the computer. There is a possibility that the contact is "lost" on one of the connectors.

Replacement instructions

How to replace an oxygen sensor with your own hands:

1. To properly remove the device, warm up the engine a little and turn off the ignition.
2. All wires are disconnected from the device.
3. Using a wrench, in some cases a socket wrench is required, it is necessary to unscrew the failed regulator. After the lambda probe is dismantled, it is also necessary to remove the protective cap, then the device is cleaned. For cleaning, you can use phosphoric acid, this option is one of the most effective. After cleaning, rinse the regulator with clean water, reinstall it and check its functionality.
4. In the event that cleaning did not give an effect, it is necessary to dismantle the old sensor and install a new one. The new component is mounted all the way; you should not put much effort. To ensure the tightness of the device, it can be treated with a sealant before installation.
5. Replace all wires.

Video "How to change the lambda probe correctly"

You can find out how to correctly replace the regulator with your own hands from the video below (the author of the video is oasex).

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Many motorists have faced the problem of increased fuel consumption. This can be due to many engine problems: faulty sensor and idle speed drive, ignition problems, decreased compression, high pressure pump failure.

But, if the fuel consumption has increased significantly (up to 50%), you should immediately check the oxygen sensors, in automotive practice they are often referred to as a "lambda probe".

What is a lambda probe in a car

The lambda probe informs the engine control unit about the amount of oxygen that has not reacted with ignition in the engine working cylinders. For complete combustion of oxygen, the mixture must be formed in a ratio of one to fifteen (more precisely 1: 14.7).

The engine control unit monitors the formation of the mixture (eliminates the causes of the formation of a rich or lean mixture) based on the readings of the sensors, including the oxygen (lambda probe).

Video - faulty oxygen sensor:

The name "lambda probe" was taken from the qualitative characteristic of the excess air ratio in the air-fuel mixture, denoted in the automotive industry by the letter of the Greek alphabet "lambda".

Oxygen sensor malfunction symptoms

The main symptoms of an oxygen sensor malfunction include:

• significantly increased fuel consumption;
• uneven engine operation, especially when the accelerator pedal is pressed;
• increased emission of toxic engine waste;
• malfunction of the catalyst.

The principle of operation of a lambda probe and common reasons for its failure

The most common reason for the failure of lambda probes is wear. A typical probe design is shown in the figure:

The weakest points of the design are the ceramic tip and the electric heater. A burnout of an electric heater does not completely damage the sensor.

The lambda probe is installed in the exhaust manifold in front of the catalyst, and as the manifold heats up with engine exhaust gases, the oxygen sensor itself is heated to a high temperature.

The electric heater is mainly used to correct the readings of the oxygen sensor in the first few minutes after starting a cold engine.

There are one- and two-wire sensors in which there is no electric heater at all.

The ceramic tip is made of special porous ceramics, on which thin zirconium dioxide is applied, the electrodes are made of platinum using vacuum deposition technology (which is why lambda probes are expensive).

During operation, very high temperature exhaust gases pass through the micropores of the sensor. A thin layer of dioxide burns out over time, oxidizes, and its electrical properties change.

As a result, the readings of the lambda probe become unreliable, in fact, it becomes unusable. In this case, all kinds of flushing, cleaning, and other methods of restoring performance are pointless.

Structurally, the principle of operation of a lambda probe can be depicted:

In the diagram: 1 - zirconium dioxide, 2,3 - electrodes (sometimes platinum), 4 - negative ground, 5 - output signal contact. The zirconium oxide probe acquires the properties of a solid electrolyte at temperatures from 300 to 400 degrees Celsius (which is why the probe is preheated). Then the lambda probe begins to register the voltage in accordance with the oxygen concentration.

As can be seen from the graph, the dependence has a pronounced step-like characteristic, which is very beneficial when processing signals by digital methods.

The following factors can accelerate the premature failure of the lambda probe:

• ingress of impurities into the exhaust system (antifreeze in case of violations of the cylinder head gasket, residual ether when using “quick start” sprays when starting the car, oil with reduced engine compression, etc.);
• high concentration of lead in fuel;
• cleaning the exhaust system with means not intended for these purposes;
• getting into the exhaust manifold of dust, impurities not removed by the fuel cleaning filter.

Many vehicles have two lambda probes, before and after the catalyst. This allows you to more accurately control the quality of the mixture, as well as check the effectiveness of the catalyst.

How to check a lambda probe with a multimeter and in other ways

It is easier to start checking the performance of the four-output lambda probes installed on most modern cars by monitoring the performance of the heating element.

To do this, switch the multimeter to the resistance measurement mode and “ring out” the leads of the electric heater. They are usually made of larger wire. The resistance should be less than 10 ohms. If the resistance is greater, this indicates a malfunction of the electrical heater.

After 10,000 km of vehicle run, it is advisable to visually check the probe. For this, the sensor must be removed from the manifold.

Many people use WD sprays or, even worse, brake fluid. The ingress of these liquids into the working area of \u200b\u200bthe lambda probe can lead to its malfunction.

Even if special means are used when loosening the coked screw connection, they should be removed immediately before removing the sensor.

In the working area of \u200b\u200bthe sensor, pay attention to its color and condition. The presence of soot (a sign of a rich mixture) leads to contamination of the sensor, for better performance, soot must be removed.

White or gray deposits are an indication of the presence of additives in the oil or fuel, they can also lead to a malfunction of the lambda probe. A shiny coating is a sign of excess lead concentration in fuel. In case of intense plaque, the sensor must be replaced.

Contact leads of the most common zirconium oxygen sensors (b, c - lambda probe with a heater; a - without; * the colors of the leads may differ from those indicated):

In order to check the lambda probe with a multimeter, it is necessary to connect its probes to the signal wires, switch to a measurement limit of 2 Volts. Further, artificially create situations of an enriched mixture, for example, by re-gasings, or by removing the pressure regulator connector. In this case, the readings of the multimeter must be more than 0.8 Volts, then the probe is serviceable.

Then a lean mixture situation is created (you can artificially create air leakage by slightly unscrewing the air duct clamp). The multimeter reading should be less than or equal to 0.2 Volts.

Video - how to check a lambda probe with a tester:

They allow you to see the parameters of the lambda probe in real time. This can also be done with a conventional oscilloscope. The time dependence of the voltage at the signal output of a working lambda probe will have an approximate form:

If the lower limit drops to 0 Volts, the sensor is pretty "tired", if the curve is smoother, the sensor must be replaced without fail.

Replacing the oxygen sensor

The mechanical difficulty of replacing a lambda probe is unscrewing a coked threaded connection. Here you may have to use special equipment. After removing the faulty sensor, carefully wipe the sensor installation site from the remaining liquids.

Video - replacing the lambda probe on the Audi A4 B5:

The original lambda probe is usually expensive (up to 6000 rubles, sometimes more). For some car models, the original sensor cannot be found, it makes no sense to buy from disassembly. In this case, it is better to install a universal lambda probe.

Universal lambda probe

The installation dimensions of the probes (thread, embedment depth) are usually the same, it is better, of course, to check so as not to damage the threaded connection or the new probe.

Universal lambda probes are sold without a connector, only with wires (usually four-wire, two signal and two for the heating element). Next, cut off the connector with wires from the old faulty native sensor and make a high-quality connection with the universal sensor in full accordance with the electrical connection diagram.

The electrical connection is best done by twisting + soldering + heat shrink insulation. Since the typical characteristics of all lambda probes made using the same technology are almost identical, the universal probes work correctly on engines of all modifications.

Video - installing a connector on a universal lambda probe:

When installing the sensor, pay attention to the tightness of the connection with the manifold, the safety of the thread.

Cleaning

Cleaning the lambda probe is a last resort. It is performed only when there is confidence that the sensor accurately shows incorrect data and the last hope before sending it to the trash can is cleaning.

A lambda probe is a device that detects the composition of the exhaust gases in order to monitor the nature of the conversion of fuel in the engine. This is a multi-component device, its components are made of heat-resistant materials. The device is installed in front of the exhaust system catalyst, and it starts functioning at a high temperature. Sometimes there are two sensors - before and after the catalyst.

As the device heats up, an output voltage appears on its electrodes. Then the lambda probe measures the residual oxygen in the car's exhaust gases. If its value deviates from the norm, a signal is sent to the ECU, which restores the composition of the fuel-air mixture.

Blende - a detail that complements the device, corrects the signal coming from it. There are two types - mechanical (gas passes through it and oxidizes, the volume of oxygen decreases, the ECU receives a more correct value of the indicator) and electronic (supports the operation of the auto powertrain adjustment system, analyzes the real composition of the exhaust, on the basis of which it corrects the signal supplied by the ECU; as a result, the engine runs in normal mode, despite a faulty catalyst or its absence).

The lambda probe is narrowband and broadband. In the first case, it is able to analyze only the standard voltage values, which can lead to malfunctions of the engine due to an incorrectly changed concentration of fuel in the fuel mixture. The broadband consists of a point-to-point and an injection element; receives oxygen from the exhaust system under the influence of current strength; keeps a constant voltage between the electrodes, and if it rises, a signal is sent to the ECU; the block then adjusts the fuel mixture.

The scheme of work of a narrow-band lambda probe

The difference between a broadband probe and a narrowband probe in that it measures the oxygen concentration in the exhaust gases at any engine speed. Its range is 0 to 5 volts. The narrowband has only 0-1.

Oxygen sensor works for 50,000-100,000 km. If you pour low-quality gasoline into the tank several times, the sensor may fail almost immediately.

If the heating of the lambda probe does not work, the device will not sense any problems with the fuel mixture. And the engine will work with increased load, and the toxicity of the exhaust gases will increase dramatically. As well as fuel consumption.

The consequences of a breakdown: the engine will begin to function unstably even at idle speed, fuel consumption increases, and poor purification of exhaust gases by a catalyst begins; the car moves in jerks, obeys poorly; the motor power is reduced.

How to understand that the device is broken: the car in motion begins to twitch; uncharacteristic sounds are heard from under the hood; the indicator on the dashboard is on; engine power decreases and the accelerator pedal operates more slowly; a sharp and unpleasant odor appears from the exhaust pipe; the motor is overheating. With a complete failure, the car may not go.

Read more in our article on how a lambda probe works.

Read in this article

What kind of device is a lambda probe

In modern cars, many sensors are installed, which not only allow better control of the operation of its various systems, but also increase environmental safety. One of the devices is a lambda probe. The device detects the composition of the exhaust gases in order to monitor the conversion of fuel in the engine.

If the ratio of fuel and air is no longer optimal, the sensor informs the electronic control unit of the injection system. He brings the mixture back to normal by decreasing or increasing the volume of supplied fuel.

How does a lambda probe work in a car

To understand how a lambda probe works in a car, you need to understand what it is made of. This is a multi-component device, its components are made of heat-resistant materials. The device is installed in front of the exhaust system catalyst, and it starts to function at a high temperature. Sometimes there are two sensors - before and after the catalyst.

As the device heats up, an output voltage appears on its electrodes. And the lambda probe acquires the ability to measure the residual oxygen in the car's exhaust gases. If its value deviates from the norm, a signal is sent to the ECU, which restores the composition of the fuel-air mixture.

What is blende and what is it for

One of the breakdowns can affect the exhaust system catalyst, after which the exhaust gas emission increases. It can be removed or replaced with a flame arrester. But the engine starts to run in emergency mode due to an incorrect lambda probe signal.

A snag can save you from this. The part complements the device, corrects the signal coming from it. There are two types of deceptions:

• Mechanical... Gas passes through such a part and is oxidized. As a result, the amount of oxygen decreases, the ECU receives a more correct value of the indicator. The system is given information in the form in which it happens with a properly operating catalyst.
• Electronic... This is a more complex microprocessor-based device. This is how the blende of an electronic-type lambda probe works: it supports the operation of the control system of the power unit of the car, analyzes the real composition of the exhaust, on the basis of which it corrects the signal supplied by the ECU. As a result, the engine runs normally, despite a faulty catalyst or its absence.

Electronic blende connection diagram

What does broadband mean

The devices are narrowband and broadband. In the first case, they are able to analyze only the nominal voltage values. That is, information transmitted at low engine speeds. Everything else is read with an error, and an incorrect signal is received by the ECU. This can lead to malfunctions of the engine due to incorrectly changed fuel concentration in the fuel mixture.

How a broadband lambda probe works:

• consists of two-point and pumping elements;
• thanks to this structure, it receives oxygen from the exhaust system under the influence of current;
• keeps a constant voltage between the electrodes, and if it rises, a signal is sent to the ECU;
• the block then adjusts the fuel mixture.

Scheme of operation of a broadband oxygen sensor

The difference with the broadband probe is that it measures the oxygen concentration in the exhaust gas at any engine speed. Its range is 0 to 5 volts. The narrowband has only 0-1.

Does the lambda probe work without a catalyst

Failure of the exhaust system catalyst (exhaust gas purifier) \u200b\u200bis one of the most common problems that causes difficulties with the operation of the engine. This happens if there are two monitoring sensors: one is installed in front of the device, and the other after it.

In this case, the oxygen content in the exhaust passed through the catalyst will change. This will detect the sensor behind it. He will transmit a false signal to the ECU about the need to correct the composition of the fuel mixture. And in this case, the answer to the question whether the lambda probe works without a catalyst is negative. After all, he gives a signal based on distorted information. Here you need to put a snag.

Another option is to rewrite the "brains" of the car, change the catalyst to a flame arrester and remove the sensor. Otherwise, injection problems will begin, which can lead to high gasoline consumption, increased engine load, and breakdown.

The oxygen sensor in some cars is located only in front of the catalyst. The lambda probe then analyzes the exhaust gases that have not yet passed through the purifier. That is, the data is not distorted, whether the catalyst is working or not. With the breakdown of the purifier, only the amount of poisonous gases from the exhaust pipe increases.

How much does it work in general

The oxygen sensor is one of the most sensitive parts of the machine. It is enough for 50,000-100,000 km of run. But how long the lambda probe works also depends on:

• car operating conditions;
• serviceability of the engine;
• type of device (unheated, heated, glider);
• fuel quality.

The last factor is especially important. If you pour low-quality gasoline into the tank several times, the sensor may fail almost immediately.

Watch this video on how the lambda probe works:

If the heating does not work

The oxygen sensor begins to analyze the composition of the exhaust after it heats up to 300-400 degrees. If the heating of the lambda probe does not work, the device will not feel problems with the fuel mixture. And the engine will work with increased load, and the toxicity of the exhaust gases will increase dramatically. As well as fuel consumption.

The only way out is to replace the sensor completely or to remove it along with the firmware of the "brain" of the machine.

The consequences of a breakdown

A malfunctioning oxygen sensor will have a detrimental effect primarily on the engine. It will start to function unstably even at idle speed. When the lambda probe does not work, the consequences are as follows:

Engine power decreases, and the accelerator pedal is triggered more slowly when it is applied;

a much sharper and more unpleasant smell appears from the exhaust pipe than before;

the motor is overheating.

From these changes, it is easy to understand how a faulty lambda probe works. If it is completely out of order, the car may not go. When the sensor is depressurized, the "brain" of the car receives many signals about problems, and the injection control system is blocked.

In short, how the lambda probe works, it keeps the engine in working order longer, saves fuel, and reduces emissions. It is necessary to regularly check it with a specialist, monitor the quality of fuel and the engine cooling system. And if the sensor fails, be sure to change it.

Useful video

See this video on how to properly check a lambda probe:

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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 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 fails gradually, which allows the problem to be identified in time.

Symptoms occur alternately:

1. 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.
2. 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.
3. The corresponding light on the dashboard comes on, which is a signal to the owner.
4. If the situation worsens, the device stops working on an unheated motor.
5. The power drops noticeably, the responsiveness when you press the gas. Pops, jerks appear more often. Engine overheating is not excluded.
6. 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. Emergency mode is activated on new car models, 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 first problems appear, you can check the status of the device.

Visual assessment:

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

Professionals use special equipment to determine the performance, to obtain accurate information. 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:

1. The motor is gradually warmed up to 75 degrees.
2. They monitor a gradual increase in revolutions to 3000, maintaining the indicators for 3 minutes. This is necessary to warm up the sensor.
3. 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.
4. 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 gassing, 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.

Checking in a car service:

1. The sensor is heated to 300 - 400 degrees for normal operation and measurement of residual oxygen.
2. 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.
3. Disconnecting the plug, determine the resistance of the heater. The indicator should remain within 2 - 14 ohms.
4. The voltage supplied to the heater is evaluated. The best option is 10.5 ohms. The test 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 plaque, the efficiency of the device is restored.

Subtleties of cleaning:

1. The procedure begins with dismantling, for which the surface of the part is heated to 50 degrees. Withdrawing the sensor, remove the protective cap.
2. Phosphoric acid is used in the work, which is able to remove carbon particles, impurities without damaging the electrodes, important elements. Soaking is carried out for 10 - 20 minutes.
3. A more complex 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. Cleaning costs are much less than replacement. This solution is suitable only for serviceable but dirty sensors. It is important to lubricate the threaded joint with assembly paste during subsequent fastening. 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.

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:

1. 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.
2. Broadband is 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.

The lambda probe (oxygen sensor) is one of the important elements in the composition, designed to measure the amount of oxygen in the exhaust gases. The sensor, monitoring the amount of oxygen in the exhaust of the vehicle, affects the quality of the vehicle's fuel mixture, thereby optimizing its performance.

The efficiency of fuel combustion lies in a properly prepared fuel mixture (the ratio of fuel to air in the fuel system). If there is more or less air, the toxicity of the exhaust gases increases, and catalysts that reduce harmful substances in the exhaust gases fail.

For this reason, it is very important to monitor the condition of the oxygen sensor, since the smooth operation of the car's internal combustion engine depends on it. At the same time, problems arising from a malfunction of the oxygen sensor are eliminated by diagnosing and carrying out repair work to replace it.

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Lambda probe: types and main components

Most often, the device is installed on the exhaust manifold, into which exhaust gases are supplied from the internal combustion engine at high temperatures and under pressure.

The main components of the oxygen sensor:

• external electrode - a metal element with a ceramic insulator and a tip coated with platinum by sputtering, calculates the amount of oxygen in the exhaust gases;
• inner electrode - zirconium element with working temperature up to 1000 ° C
• heating element - an element that heats the electrodes to certain temperatures, which allows the oxygen sensor to work at the time of a cold start of the internal combustion engine.

• broadband sensor - has a two-point and pumping ceramic elements (the pumping element, using a certain current strength, pumps oxygen into itself from automobile exhaust gases).
• a two-point sensor - has two electrodes and calculates the excess air ratio in the fuel mixture. The coefficient under ideal conditions should be equal to 1, low-quality fuel and air raise it to a mark, for example, 1.05;

Lambda probe malfunctions: symptoms and causes

Failure of the lambda probe can lead to a malfunction of the fuel system, an increase in fuel consumption, a decrease in traction, etc. A malfunction of the fuel system will lead to a decrease in the performance of the car's engine: deterioration in dynamics, etc.

The service life of the oxygen sensor depends on the operating conditions of the car's internal combustion engine and averages 60-80 thousand kilometers.

The main symptoms of a lambda probe malfunction:

• excessive fuel consumption;
• uncharacteristic odor from the exhaust pipe, increased toxicity of exhaust gases;
• transition of the internal combustion engine to emergency mode, deterioration of dynamics, decrease in power (strongly noticeable when driving at high speeds);
• unstable idle,;

Lambda probe malfunction, reasons:

• low quality fuel (high content of impurities, in particular, lead);
• violation of the integrity of electrical connection circuits (short circuit);
• mechanical damage or contamination of the oxygen sensor with fuel combustion products due to problems with the engine;
• temperature overloads (interruptions in the operation of the ignition system).

It is also worth noting that a breakdown of the oxygen sensor can lead to itself in operation (violation of the functionality of the vacuum valve of the system).

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