During the operation of the car, various malfunctions occur in the fuel system. You can determine the malfunction by paying attention to the behavior of the car on the road. But first you need to figure out what types of fuel systems are, what components and parts it consists of.

Types of fuel systems

There are diesel and petrol engines. They run on different fuels, respectively, they have different fuel systems.

At diesel engines fuel from the tank through the pipes is supplied by a fuel priming pump to the injection pump (high pressure fuel pump), then from the injection pump to the injectors. From the injectors, fuel enters the cylinder directly through intake manifold engine.

There is no such pressure in gasoline engines - gasoline does not need such a high compression ratio to burn gasoline. Fuel systems gasoline engines differ in type. There is a distributed injection system (injector), a single-point injection system (single injection) and a carburetor. Carburetor engines have recently been discontinued and are living out their last days.

Fuel System Parts

Regardless of the type of engine, any fuel system consists of fuel pump, fuel pipes and directly to the device that supplies fuel to the intake manifold. Such a device is almost always a nozzle, in carbureted engines this role is performed by the carburetor.

V modern engines use sensors that affect the quality combustible mixture and on fuel consumption. As part of the injector and single injection there is an idle speed controller and a position sensor throttle valve. The air flow sensor is present in injectors and modern diesel systems. Oxygen sensor(lambda probe) has been installed in recent years on almost all types of engines.

The device and principle of operation of the oxygen sensor

The oxygen sensor (lambda probe) is located in the car's exhaust system. Depending on the complexity of the design, one or two sensors can be installed, and there are more. If there is one lambda probe, then it is located on the exhaust manifold.

The lambda probe is a ceramic element in a metal case, to which voltage is applied through wires. Ceramics, depending on the qualitative composition of gases in the exhaust system, sends a signal to the control unit. Fuel management is adjusted according to the sensor readings.

What causes an oxygen sensor to fail

The most banal thing that can cause a lambda probe to fail is mechanical damage. Let's say your car has been in an accident. Often, in our Russian conditions, the quality of the fuel is to blame. It's no secret that gasoline at gas stations in Russia is often "bodya".

Poor engine condition affects sensor performance. A faulty piston group throws out motor oil v exhaust system, thereby clogging the ceramics at the "lambda".

An incorrectly adjusted ignition leads to overheating of the sensor. Due to the same ignition, pops may appear in the muffler. Strong pops destroy the lambda probe.

Disables the oxygen sensor antifreeze and brake fluid that fall on the ceramic insulator. This may be due to leakage of fluids in brake system and cooling system.

The main symptoms of lambda probe malfunctions

You can understand whether the oxygen sensor is working or not by some characteristic signs. Although the cause of the problem may be different, professional diagnostics are needed to accurately determine the defect.

A faulty oxygen sensor could be if:

• - the car on the road moves with jerks,
• - increased fuel consumption,
• - the car "stupid", rides badly and picks up speed,
• - the engine runs erratically at idle,
• - immediately after stopping, a characteristic crack is noticeable in the area where the "lambda" is located,
• - during an external examination of the sensor, it turns out that it has heated up to a red-hot state (turned red).

If the wires are broken at the sensor, then there is no doubt - in this state it will not work. In the presence of external damage, one can doubt the operability of the lambda probe.

The Check Engine warning lamp in the passenger compartment also indicates any malfunctions in the engine's electrical system, but a malfunction can only be accurately determined using computer diagnostics.

Oxygen sensor replacement

Replacing a lambda probe on a car is very simple, especially if the sensor is located on the exhaust manifold (it is more convenient to get to it). It is better to change it on a well-heated engine, as the cold metal shrinks, and the sensor often "sticks" to the manifold.

To replace you need:

• - turn off the engine and turn off the ignition,
• - disconnect the wires at the connector,
• - use a wrench (sometimes a socket wrench is required) to unscrew the faulty sensor,
• - screw the new sensor into place until it stops until it stops, but without any extra effort,
• - connect the wires at the connector.

That's it, pretty basic. Now there will be no problems with the new sensor.

The purpose of the lambda probe (oxygen sensor) is to transfer information about the composition of the working mixture from the exhaust manifold to the computer. Combustion quality fuel-air mixture(TVS) directly affects the operation of the engine.

For modern cars with injection engine put one or more catalysts and two or more oxygen sensors. Where is the lambda probe? Depends on the type of car. Common systems with two devices, which are located before and after the catalyst. In this way, the excess of oxygen in the mixture is determined before the gases enter the device. In cars 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 with the help of injectors, setting the volume at a certain moment. The probe provides feedback, which allows you to accurately determine the proportions of gasoline, diesel or gas. The ECU requests information once every 0.5 seconds at idle. On the increased speed the frequency of requests increases proportionally. Analyzing the data, the control unit corrects the composition of the fuel assembly, making it poorer or richer. Maintaining an optimal TVS is the purpose of lambda probes. The ideal ratio of air and fuel is 14.7:1 (gasoline), 15.5:1 (gas) and 14.6:1 (diesel).

• Point-to-point, narrowband (simple). It works based on the measurement of the amount of oxygen in the exhaust gases. The poorer the fuel assemblies, the lower the voltage, the richer the higher.

Average life span of oxygen sensors per Russian gasoline 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 may be wear, low quality gasoline, mechanical damage and other factors.

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

• Fuel consumption increases. Each motorist monitors the fullness of the tank, tries to find his cruising speed when flow is at a minimum. Therefore, increased fuel consumption will notice immediately. Depending on the severity of the malfunction of the lambda probe, it grows by 1-4 liters. Increased consumption, of course, can cause more than just a faulty oxygen sensor.

How to test a lambda probe

The procedure is as follows:

1. Test the probe signal with a motor tester, pointer voltmeter, or oscilloscope. Connect the 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 change is less or less than 9-10 readings have changed in 10 seconds. The cause of the error may be in the "fatigue" and slow response of the system.

Video instruction:

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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 computer. The quality of combustion of the fuel-air mixture (FA) directly affects the operation of the engine.

Correct operation of the oxygen sensor helps:

• Increase engine performance by determining close-to-ideal proportions of injected fuel and air.
• Reduce the production of harmful gases (CO, CH, NOx) emitted into the atmosphere and improve the economical operation of the car due to the correctly selected 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? Depends on the type of car. Common systems with two devices, which are located before and after the catalyst. In this way, the excess of oxygen in the mixture is determined before the gases enter the device. In cars 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 with the help of injectors, setting the volume at a certain moment. The probe provides feedback, which allows you to accurately determine the proportions of gasoline, diesel or gas. The ECU requests information once every 0.5 seconds at idle. At higher speeds, the frequency of requests increases proportionally. Analyzing the data, the control unit corrects the composition of the fuel assembly, making it poorer or richer. Maintaining an optimal TVS is the appointment of lambda probes. The ideal ratio of air and fuel is 14.7:1 (gasoline), 15.5:1 (gas) and 14.6:1 (diesel).

Types of oxygen sensors by design and principle of operation:

• Point-to-point, narrowband (simple). It works based on the measurement of the amount of oxygen in the exhaust gases. The poorer the fuel assemblies, the lower the voltage, the richer the higher.
• Broadband. Generates a wider range signal for accurate aspect ratio estimation in TVS.

The average life expectancy 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 may be wear, low quality gasoline, mechanical damage and other factors.

If you suspect a malfunction of the oxygen sensor, contact professional diagnosticians. With the help of an oscillogram, a specialist will determine the causes of the malfunction and suggest solutions.

What causes the lambda probe to fail

• Mechanical damage. A strong impact resulting from an accident, hitting a curb, or driving off-road adversely affects the condition of the probe;
• Incorrect engine operation and ignition system malfunctions lead to overheating of the oxygen sensor and breakdown;
• System clogging. The main cause of a malfunction of the lambda probe will be the products of combustion of low-quality fuel. The more heavy metals, the sooner it will clog;
• Breakdown in piston group. A faulty piston, piston 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;
• misfiring;
• Additives and "improvers" of fuel;
• Natural wear. In conditions of low-quality fuel, the average service life of the sensor is 40–70 thousand km.

Failure of the lambda probe occurs gradually. The consequences of a faulty oxygen sensor translate into emergency mode engine control. So manufacturers save the car from serious breakdowns, and the driver from emergency situations.

Symptoms of a lambda probe malfunction

• The level of toxicity of gases increases. Toxicity can be determined through 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 cruising speed when the consumption is minimal. Therefore, increased fuel consumption will notice immediately. Depending on the severity of the malfunction of the lambda probe, it grows by 1-4 liters. Increased consumption, of course, can cause not only a faulty oxygen sensor.
• Oxygen sensor errors are issued (P0131, P0135, P0141 and others), “ check engine". Usually a check appears when there is a malfunction of the probes or the catalyst. Diagnostics will establish the exact cause.
• The catalyst is overheating. Faulty lambda probes give incorrect signals to the computer, which can lead to incorrect work catalyst, its overheating up to a red-hot state, and subsequent failure.
• There is jerking and uncharacteristic pops in the engine. Lambda probes stop generating the correct signal, which destabilizes the idle speed. The revolutions fluctuate in a wide range, which leads to a deterioration in the quality of the fuel mixture.
• get worse dynamic characteristics car, power, traction is lost. Similar signs appear in neglected situations. Faulty sensors also stop working on cold engine, and the machine signals problems in the system in various ways.

If you are concerned about any of these signs, see a specialist. Via diagnostic equipment he will determine the exact area of ​​\u200b\u200bthe breakdown and help in fixing it.

How to test a lambda probe

So, the car is jerking, fuel consumption has increased, the “Check Engine” caught fire. The signs are not typical only for a breakdown of the lambda, so a complete diagnosis of the systems is needed. But if you are sure that this is the case, we tell you how to check the sensor yourself.

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 coated with soot, lead, white or gray soot, replace it.
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 call him? Attach an ohmmeter between the heater wires, previously disconnected from the block. When working properly, the resistance of the signal circuit at different cars 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 a break in the wiring.
4. Test the probe signal with a motor tester, pointer voltmeter, or oscilloscope. Connect the 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 change is less or if less than 9-10 readings have changed in 10 seconds. The cause of the error may be in the "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 the circuits in the circuit leading to it are faulty.

If there are no devices to check the performance of the lambda probe, contact the specialists. They will hold complete diagnostics and will accurately name the cause of the malfunction for less money and time that you would spend on buying devices and identifying the malfunction yourself.

Video instruction:

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First things first when out of order and labda malfunctions in the behavior of the car there are several tangible consequences:

• Unstable operation of the car engine (jerks)
• The work of the catalyst is disrupted (toxicity increases)

Then, to check the lambda probe, you can first unscrew and conduct a visual check (just as it can tell a lot).

Several types of lambdas are installed on cars, sensors can be with one, 2, 3, 4 or even five wires, but it is worth remembering that in any of the options one of them is signal (often black), and the rest are designed for heater (usually they are white).

What and how can I check the lambda

To check, you will need a digital voltmeter (preferably an analog voltmeter, since it has a much shorter “sampling” time than a digital one) and an oscilloscope, if possible, the measurements will be more accurate. Before checking, you should warm up the car because the lambda works correctly at temperatures above 300C °.

First, we are looking for a heating wire:

We start the engine, do not disconnect the lambda connector. The negative probe of the voltmeter (usual tseshka) is connected to the car body. With the plus probe of the shop, we “poke” on each contact of the wire and observe the reading of the voltmeter. When a positive wire of the heater is detected, the voltmeter should show constant 12 V. Next, using the negative probe of the voltmeter, we try to find the negative wire of the heater. We turn on the remaining contacts of the sensor connector. When a negative contact is detected, again, the voltmeter will show 12 V. The remaining wire, signal wires.

Checking the lambda probe with a tester

We take an electronic constant voltage millivoltmeter and connect it in parallel with the LZ (“+” “-” to the LZ, - to the ground), and the lambda probe must be connected to the controller.

When the engine warms up (5-10 minutes), then you need to look at the voltmeter needle. It should periodically go between 0.2 and 0.8 V (i.e. 200 and 800 mV, moreover, if less than 8 cycles occur in 10 seconds, it’s time to change the LZ. Also to be replaced if the voltage “stands” at 0 .45 V.

When the voltage is 0.2 or 0.9 V all the time - something with injection - the mixture is too lean or too rich. Since the voltage of the oxygen sensor should change all the time and jump from ≈0.2 to 0.9V.

There is another fast lambda probe test method. It should be done like this:

It is carefully pierced with the positive contact of the tester (black lambda wire), the other contact is to ground. On a running motor, the readings should fluctuate from 0.1 to 0.9V. Constant readings (for example, all the time 0.2) or readings that go beyond these limits, or fluctuations with a smaller amplitude, indicate a malfunction of the probe.

Exceptions:

• all the time 0.1 - little oxygen
• all the time 0.9 - a lot of oxygen
• The probe is OK, the problem is something else.

If you have time and desire to bother, you can conduct several tests for a rich and lean mixture and additionally.

1. Disconnect the oxygen sensor from the block and connect it to a digital voltmeter. Start the car, and by pressing the gas pedal, increase the engine speed to 2500 rpm. Using an enricher, reduce the rpm to 200 rpm.
2. If your vehicle is equipped with an electronic fuel system, remove the vacuum tube from the fuel pressure regulator. Look at the voltmeter readings. If the arrow of the device approaches 0.9 V, then the lambda probe is in working condition. The lack of reaction of the voltmeter testifies to it, and its readings are within the lower mark of 0.8 V.
3. Do a lean mixture test. To do this, take a vacuum tube and provoke an air leak. If the oxygen sensor is good, the digital voltmeter will read 0.2 V or less.
4. Check the operation of the lambda probe in dynamics. To do this, connect the sensor to the connector of the fuel supply system, and install a voltmeter in parallel with it. Increase engine speed to 1500 rpm. The voltmeter readings with a working sensor should be at the level of 0.5 V. Another value indicates the failure of the lambda probe.

Checking the voltage in the heating circuit

A voltmeter is needed to check for voltage in the circuit. We turn on the ignition and connect it with probes to the heater wires (you cannot disconnect the connector, it is better to pierce it with sharp needles). Their voltage should be equal to what the battery gives out on not running engine(about 12V).

If there is no plus, you need to go through the battery-fuse-sensor circuit, since it always goes directly, but the minus comes from the computer, so if there is no minus, we look at the circuit to the block.

Checking the lambda probe heater

In addition to measuring the voltage with a multimeter, you can also measure the resistance to check the health of the heater (two white wires), but you will need to switch the tester to Ohms. The documentation for a particular sensor must indicate the nominal resistance (usually it is about 2-10 ohms), your task is only to check it and draw a conclusion. The video shows this method:

Checking the reference voltage of the oxygen sensor

We switch the tester to the voltmeter mode, then, turning on the ignition, we measure the voltage between the signal and the ground wire. In most cases, the reference voltage of the lambda probe should be 0.45V.

Most cars manufactured since the late 70s and early 80s are equipped with catalytic converters exhaust gases(colloquially -), which can significantly reduce the toxicity of waste materials, reducing the damage to the environment. Enough interesting fact is that the catalyst can retain functionality only under conditions of ideal mixture formation, in which 1 part of the fuel accounts for from 14.6 to 14.8 parts of atmospheric air with a normal oxygen content. To prevent the mixture from being over-enriched or over-depleted, it is necessary to apply electronic control fuel supply - in such a system, the quality of the combustible composition is controlled by a lambda probe. Despite its location in an aggressive environment, this device is quite fragile and unstable, and is subject to frequent. If the lambda probe stops working in your car, signs of a malfunction can be detected without specialized equipment - continue to operate vehicle impossible.

Mechanism of action

The lambda probe determines the chemical composition by searching for oxygen in them and determining the percentage. In the normal state of the mixture, this figure is 0.1–0.3% - slight fluctuations are allowed due to the fact that the mode of fuel supply to the engine cannot be stable for a significant period of time. The lambda probe is installed directly into the exhaust manifold - usually its installation is carried out at the junction of pipes extending from various cylinders (colloquially - "pants"), although there are other options.

There are various modifications of lambda probes - as well as vehicles of previous years of production, the devices have a two-channel layout. They can only determine the presence of a deviation in the oxygen content in a positive or negative side, which is accompanied by a change in the voltage of the electrical signal transmitted to the electronic unit. However, all modern cars of the middle and elite classes are already equipped with broadband type lambda probes, which are already designed to determine the percentage deviation of the content of the desired element from the norm. Thanks to this, a significant improvement in the performance of the motor is achieved:

• Increases the stability of holding speed;
• Reduced fuel costs;
• The resource of the vehicle increases.

If you are interested in the electrical side of the lambda probe, then it is worth mentioning that this device cannot generate a uniform signal. Due to the fact that the standard lambda probe is located in the exhaust manifold, when the exhaust gases reach the point of its location, several work cycles may already have passed. At the same time, the quality of mixture formation deteriorates by 3–5%, which is accompanied by some destabilization of the engine. The lambda probe reacts to this by changing the voltage supplied to the central injection control unit, which takes the necessary measures.

We determine the breakdown

External signs

In the event of a malfunction of the lambda probe, a significant deterioration in the quality of the fuel mixture occurs, which is outwardly expressed in a deterioration in the operation of the engine. It is worth saying that there can be many - among them are the following main ones:

• Depressurization of the sensor housing, penetration of atmospheric air and exhaust gases into the interior;
• Overheating of the lambda probe as a result of inept tuning of the motor;
• Failure as a result of prolonged exposure to an aggressive environment (aging);
• Blocking of the working surface of the lambda probe by the products of combustion of low-quality fuel;
• Violations of the normal power supply and interruption of the line leading to the control unit;
• A strong blow to the body of the lambda probe with the destruction of internal components, for example, when actively driving on bad roads.

In all cases, except for mechanical damage accompanied by depressurization, malfunctions of the lambda probe appear gradually, with stepwise deterioration. Another exception is a broken wiring - however, it cannot be considered a malfunction of the lambda probe itself, so it should be considered in a separate topic for discussion. For all others, the following stages of development of faults can be distinguished.

Video on how to check a lambda probe:

At first, the device ceases to perform its functions normally in the limiting modes of engine operation, when its electrical characteristics are already deteriorating so much that the sensor cannot form. A malfunction of the lambda probe is manifested in the destabilization of the idle speed, which begin to “float” in a fairly wide range, the length of which is 300–600 rpm. Upon reaching very high speed, which do not belong to a critical level, a sharp change in the quality of the fuel mixture can occur. In this case, the car can twitch strongly, jerky pops can be heard from under the hood in some cases, and a warning lamp flashes on the engine, signaling abnormal engine operation. With a decrease in speed, all signs of a breakdown of the lambda probe disappear, but they cannot be ignored.

At the second stage, the device stops working on a cold engine - until the temperature reaches the maximum possible, the car will show all signs of a malfunction in the intake system or gas distribution mechanism. In particular, you will notice a significant reduction in power, extremely slow reactions to changes in the position of the gas pedal, as well as jerks and pops. In the event of a malfunction of the lambda probe, the car may twitch, slow down sharply as a result of a complete stop in the fuel supply, and. After about 5-10 minutes of driving in this unpleasant mode, there is a visible stabilization of the condition of the vehicle - however, this is only temporary.

If you do not take any measures regarding malfunctions of the lambda probe at the previous stage, the device will permanently fail, which will cause many negative consequences. In addition to a significant deterioration in dynamics and the impossibility of normal movement in continuous mode, you will encounter an increase in fuel consumption by 15-30%, as well as a significant increase in exhaust toxicity, which can be determined by a clearly perceptible shade of fuel. Modern cars can generally block all driver actions in the event of a faulty lambda probe by switching to emergency mode.

Worst case

If the lambda probe depressurization mentioned above has occurred, it is impossible to continue operating the car, as this can become a prerequisite for a complete failure of the engine, followed by expensive repairs. In this phenomenon, the exhaust gases enter a duct that is used to take atmospheric reference air in order to compare the two gases and determine the optimal oxygen content. If engine braking occurs, atmospheric air passes through with a minimum amount of impurities - therefore, the lambda probe sees that there is much more oxygen in the oxygen collector than in the environment! The result of this is the formation of powerful negative signals that completely disrupt the normal operation of the injection control unit.

Electronic diagnostics

If you want to know what signs of a malfunctioning lambda probe can be found during a professional inspection, you should find specialized equipment. When examining a lambda probe, an electronic oscilloscope is used - some experts recommend using a multimeter, but it can only state the fact that the device has failed. The device is checked on a running engine, heated to a circuit temperature of 80–90 degrees. In a cold state, the sensor may give readings that deviate significantly from the norm.

There can be many signs of a malfunctioning device. They are represented by flat signal characteristics or a level increase not exceeding 0.1 V. In addition, you should pay attention to the shape of the curve - the changes should be steep enough to prevent a smooth increase in voltage. Experts say that the lambda probe must change the signal level every 120 ms - otherwise it is possible to talk about its malfunction.

Car repair

Almost all manufacturers of vehicles and individual components for them claim that the lambda probe cannot be repaired - only complete replacement node. At the same time, its cost can be quite impressive - especially if you are the owner of a luxury brand car. A common way out is to purchase a universal sensor equipped with a special adapter for a specific type of vehicle. These devices are manufactured by Bosch - using their services, you can even purchase used remanufactured parts, which are distinguished by a reduced cost and a limited duration. In addition, you can buy a used exhaust manifold with a pre-installed lambda probe.

If you are absolutely sure that the lambda probe is not functioning properly as a result of the deposition of combustion products on it, you can try it. To do this, the device is dismantled at a surface temperature of 40–50 degrees, the protective cap is removed from it, and the contacts are immersed in phosphoric acid. After several washes, the lambda probe is washed with clean water, dried thoroughly and put in place, not forgetting to lubricate the threads with a special sealing paste. The tightening torque is set by the manufacturer - it usually varies between 40–60 Nm. A similar procedure helps in 80% of the cases of the described malfunctions.

The main thing is timely diagnosis

If you find out in time that the car’s malfunction lies precisely in the breakdown of a standard lambda probe, you can carry out necessary repairs even before the consequences affect the engine, leading to its significant damage. In addition, by fixing a similar problem, you can save the most important characteristics the vehicle at the same level, which will help you to use it as fully and profitably as possible. It is up to you to decide which troubleshooting method to choose, but it is worth remembering that working with car electronics without the appropriate qualifications is very dangerous.

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

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

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

Common Causes:

• 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 a lot of additives that increase the octane number;
• air, exhaust gases can enter the system.

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

Symptoms appear in sequence:

1. There is an unstable idle. The reason is that at certain moments the signal is not generated. Fluctuations can be serious, in a wide range.
2. The quality of the air-fuel mixture decreases. This is accompanied by the appearance of jerks, uncharacteristic pops in the work. power unit. The dynamics are deteriorating.
3. The corresponding lamp lights up. dashboard, which is a signal to the owner.
4. If the situation worsens, cold engine the device stops working.
5. Power drops noticeably, responsiveness when you press the gas. Claps, jerks appear more often. Engine overheating is not ruled out.
6. Fuel consumption is growing, exhausts acquire a toxic smell.

In such a situation, it is necessary to replace the lambda probe; symptoms of a malfunction should not be ignored. On new car models, emergency mode is activated, which makes it impossible to continue driving. 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:

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 indicates a large amount of additives in the fuel, which affects the performance of the unit.
3. Brilliant streaks suggest that the content of lead particles in the fuel has been increased.

To determine the performance, 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 stages:

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

When thinking about how to check the lambda probe, they take into account that if the readings of the device do not change during the process, a voltage of 0.5 volts is maintained during gassing, the unit is probably faulty. With zero data, you need to make sure that the sensor is connected to ground. It is recommended to check the integrity and serviceability of the wiring leading to the ignition switch, relay.

Benefits of using 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:

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. After disconnecting the plug, determine the resistance of the heater. The indicator should remain within 2 - 14 ohms.
4. The voltage applied to the heater is estimated. The best option- 10.5 ohms. The test is performed with the ignition on with the probe connector connected.

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

Can the probe be cleaned

If the oxygen sensor breaks down, you cannot do without replacing it, since there are no methods for its restoration. Given the high cost of spare parts, repairs can be accompanied by considerable costs.

But there are other options:

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

But it is not always necessary to change the spare part. It is enough to know how to clean the lambda probe. After all, situations of severe pollution are not ruled out. On the sensitive element, covered with a protective cap, particles of soot and soot can be deposited. Because of this, there are malfunctions and errors in the work. After the plaque is removed, 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. After removing the sensor, remove the protective cap.
2. In the work, orthophosphoric acid is used, which is able to remove particles of soot, dirt, without damaging the electrodes, important elements. Soaking is carried out for 10 - 20 minutes.
3. More difficult option involves removing the protective cap and washing using the finest brush. After removing dirt, the part is washed and dried.

Washing is carried out if it is possible to reinforce the protection, which involves argon welding. The cost of cleaning is much less than replacement. This solution is only suitable for serviceable but contaminated sensors. During subsequent fixing, it is important to lubricate the threaded connection with assembly paste. When installing a new element, lubrication is not required, the connection is processed at the time of production.

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

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

A properly functioning probe provides:

• reduction of fuel consumption up to 15%;
• improving the environmental friendliness of exhaust gases;
• the factory life of the catalyst is preserved;
• excellent dynamics and 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.

Device types:

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 exhaust gases. Here the first element is sensitive to oxygen. The second is made from zirconium. At the time of passage of the exhaust between the electrodes, the potential is measured. An increase in the indicator means an excess of oxygen.
2. Broadband represent a new type of probes. A voltage of 450 mV is stored here. The device includes ceramic components - two-point and pumping. 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, save the factory resource, the functionality of the nodes.