Breakage of the lambda probe what will happen. Lambda oxygen sensor - probe: malfunctions, inspection and repair. Lambda probe repair or complete replacement of the lambda probe assembly

First things first, in case of failure and malfunctions several tangible consequences appear in the behavior of the car:

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

Then, to check the lambda probe, you can first unscrew and carry out 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, even five wires, but it is worth remembering that in any of the options one of them is a signal (often black), and the rest are intended for heater (they are usually white).

How and how you can 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, measurements will be more accurate. Before checking, you should warm up the car since the lambda works correctly at temperatures over 300C °.

First, we are looking for a heating wire:

We start the engine, do not disconnect the lambda connector. We connect the minus probe of the voltmeter (a regular shop) to the car body. With the positive probe of the chain we "poke" on each contact of the wire and observe the reading of the voltmeter. When the positive wire of the heater is found, the voltmeter should show constant 12 V. Next, with 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. If 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 millivoltmeter constant voltage and we connect it parallel to 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 replace if the voltage "stands" at 0 , 45 B.

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

There is another quick way to check the lambda probe... It should be done like this:

Gently pierce the positive contact of the tester (black lambda wire), the other contact to ground. With the motor running, the readings should fluctuate from 0.1 to 0.9V. Constant readings (for example, all the time 0.2) or readings outside this range, or fluctuations with a lower amplitude indicate a probe malfunction.

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 pozamorachivatsya, you can conduct several tests for a rich and poor mixture and additionally.

1. Disconnect the oxygen sensor from the shoe and connect it to a digital voltmeter. Start the car, and, pressing the gas pedal, increase the engine speed up to 2500 rpm. Using the enrichment device fuel mixture, arrange a reduction of revolutions to 200 per minute.
2. Provided that your car is equipped fuel system electronically controlled, remove the vacuum pipe from the fuel pressure regulator. Look at the voltmeter reading. If the arrow of the device approaches 0.9 V, it means that the lambda probe is in working order. This is evidenced by the lack of response of the voltmeter, and its readings are within the limits of less than 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 reading will be 0.2 V or less.
4. Check the operation of the lambda probe in dynamics. To do this, connect the sensor to the fuel supply system connector and install a voltmeter parallel to it. Increase engine speed to 1500 rpm. The voltmeter readings with a working sensor should be at a level of 0.5 V. Another value indicates a failure of the lambda probe.

Checking the voltage in the heating circuit

A voltmeter is needed to check the presence of voltage in the circuit. We turn on the ignition and connect it with the 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 that of the battery when the engine is not running (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 ECU, 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 resistances to check the health of the heater (two white wires), but you will need to switch the tester to Ohms. In the documentation for a specific sensor, the nominal resistance is necessarily indicated (usually it is about 2-10 ohms), your task is only to check it and draw a conclusion. The video shows this method:

Oxygen sensor reference voltage test

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

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

European carmakers, under the yoke of environmentalists and new bills that demand to limit emissions harmful substances into the atmosphere, they resort to the use of various new units in every possible way. Most often these are various neutralizers or catalysts - devices that actively reduce the amount of harmful substances in the exhaust of a car.

Basic functions of a lambda probe

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

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

Principle of work

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

Malfunctions

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

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

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

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

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

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

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

Testing the probe

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

This article will talk about what a lambda probe is, we will also consider the symptoms of a malfunction of this node. It is also called an oxygen content sensor. It is installed in the exhaust tract car engine internal combustion... Moreover, this sensor is installed on both gasoline and diesel engines.

Oxygen Sensor Basics

The lambda probe is similar in its principle of operation to a solid ceramic electrolyte based on zirconium. The ceramics were also alloyed with yttrium oxide. Above is a thin layer of spraying c It turns out that one electrode perceives the exhaust gas, while the other - air from the atmosphere. It is due to this that the parameters of the working gas are compared with normal atmospheric air. It is also worth noting that the most effective work is carried out at temperatures above 300 degrees. It is with this heating that the zirconium electrolyte begins to conduct current. And now it's time to learn about what affects how a lambda probe works. For example, the Priora malfunction symptoms can be determined even by ear.

The principle of operation of the lambda probe

Due to the fact that there is a difference in the mass content of oxygen, a output voltage... To increase the sensitivity of the device at low temperatures, for example, when starting the engine, it is necessary to use forced heating. The electric coil is located in the ceramic body of the lambda probe. It has a connection to the vehicle's on-board network. There is also an oxygen sensor element, which is based on It changes its resistance when the engine is running. This is how the lambda probe works. The symptoms of VW Golf 3 malfunction are the same as in domestic cars.

Oxygen sensor operation

At the moment when the engine starts and warms up, the engine operates without data coming from the lambda probe. All correction of the air-fuel mixture is carried out according to data received from other devices. In particular, these are throttle valves, engine temperature, crankshaft speed. main feature a lambda probe based on zirconium is that with a slight deviation from the oxygen content norm when analyzing the composition of the fuel mixture, there is a significant change in the output voltage in the range of 0.1-0.9 Volts.

Titanium oxygen sensors

Titanium dioxide sensors are also available. Then, when there is a change in the mass fraction of oxygen in the exhaust gases, they gradually change the resistance in volume. No voltage is generated in sensors of this design. They are much more difficult than zirconium ones, they are used for very expensive cars eg BMW, Nissan, Jaguar. On budget cars devices based on titanium, as a rule, are not used because of their high cost. On cars of the middle and low class, the cheaper zirconium one uses a lambda probe. Signs of malfunction "Renault-Megan 2" shows such that are no different from those present on domestic cars.

Differences between lambda probes

It is worth noting that the principles of operation of oxygen sensors are the same, regardless of who the manufacturer is. The only difference is in the dimensions of the body of these elements. There may also be a slightly different connection, often there is a difference in the connector. All sensors, as mentioned above, are heated or not. Therefore, they differ in the number of wires for connection. According to the materials, the differences are as follows: either zirconium or titanium. In the latter, the heater output is always red. There are also types for diesel engines... They are more broadband. Cannot be installed on gasoline engine such a lambda probe. Symptoms of a malfunction (Skoda-Octavia is also of interest to many motorists) are accompanied by an error code with a short description.

Why does the lambda probe fail?

Very often, the cause of premature failure is the poor quality of gasoline. Iron and lead, which may be present in bad gasoline, instantly clog the platinum electrodes. Consequently, the oxygen sensor fails, it cannot normally take all readings. If they have a strong output, then a certain amount of oil will get into. This is also the cause of the premature failure of the oxygen sensor. Even if a little solvent or detergent accidentally gets on the oxygen sensor, you can immediately say that it is broken. He does not survive the ingress of such solutions. Destruction of the lambda probe occurs when in exhaust system there are pops. Ceramics are very fragile, so sharp impacts like these can destroy them. If the ignition angle is incorrectly set or if the air-fuel mixture is too rich, the sensor housing will heat up strongly. This becomes the cause of premature failure.

Less popular causes of breakage

Please note that when installing the lambda probe, you cannot use various sealants that are based on silicone. You can also destroy the lambda probe if you try to start the engine many times, making short pauses between attempts. Provided the engine will not start. This will necessarily lead to the fact that the air-fuel mixture will accumulate in exhaust system... After some time, it will ignite and create a powerful blast wave. Even a poor-quality contact or in the output circuit that can destroy the device. The total resource of the elements ranges from 30..70 thousand kilometers. It largely depends on the conditions under which the operation takes place. The longest service life is for sensors with additional heating. Most foreign cars use such a lambda probe design. The symptoms of malfunction ("Ford Focus 2" or "Skoda" are in your possession) are the same. Therefore, you can diagnose yourself if you correctly recognize all the symptoms.

Frequent sensor breakdowns

Among the most popular breakdowns, one can note an inoperative heating element, as well as loss of sensitivity. Due to the latter, the speed of the device decreases. Most importantly, try not to replace the lambda probe with any imitators. The electronic control unit will not be able to recognize someone else's signal. Therefore, the fuel mixture correction for this simulator will not occur. Please note that if the oxygen sensor has successfully worked in the conditions of our country (low-quality gasoline), and its service life is clearly more than three years, then you do not even need to contact the diagnostician. It is immediately necessary to replace the lambda probe. The Skoda clearly shows signs of malfunction when the vehicle has been driven over 70 thousand km. Some models of oxygen sensors may even have a resource of just over 30 thousand kilometers.

How to tell if a sensor is defective

If present unstable work motor on low revs, it feels like the engine is "troit". And at the same time, the consumption of gasoline increases, the dynamics of the car worsens. Often you can hear a crackling noise coming from the catalytic converter after you turn off the engine. It is also possible to increase the (significant) temperature of the catalyst itself. Sometimes it heats up so much that the metal simply heats up. In some cars, the malfunction can also be judged by the warning lamp. Check Engine... Only, unfortunately, not all systems electronic control allow you to identify and indicate the malfunction of this element.

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

The need for an oxygen sensor

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

A bit of history

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

Principle of operation

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

Operating conditions of the lambda probe

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

Broadband

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

How to determine a breakdown

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

Emergency firmware

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

Conclusion

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

A lambda probe is an O 2 concentration sensor (or, more simply, an oxygen sensor) that allows you to estimate the amount of unburned oxygen contained in exhaust gases. These indicators are extremely important, since due to the maintenance of certain proportions of fuel and air, the most efficient combustion of the air-fuel mixture occurs. The best ratio is considered to be 14.7 parts of oxygen per 1 part of gasoline. If this ratio is violated, then the mixture will be lean or, conversely, rich, which, in turn, will affect fuel consumption and engine power.

Although outwardly the oxygen sensor does not look like a "vital" part, it performs a very important function, so any malfunction of the lambda probe, the "symptoms" of which we will consider, must be immediately corrected.

Signs and causes of a malfunction of the lambda probe

According to statistics, oxygen sensors fail gradually, so you can identify its malfunction if you pay attention to the following "symptoms" in time:

• The idle speed began to fall or "float".
• The car jerks, and after starting the engine, you hear claps uncharacteristic of the engine.
• The engine power has decreased and a delayed reaction is observed when the gas pedal is pressed.
• The engine overheats a lot and fuel consumption has increased.
• The smell in the exhaust pipe has changed ( traffic fumes become more toxic).

As a result of a failed sensor, the quality of the fuel mixture entering the combustion chamber deteriorates, which disrupts the smooth operation of the engine. There can be many reasons for this:

• Incorrect operation of the heating circuit or reduced sensitivity of the sensor tip.
• Low-quality fuel with a high content of iron, lead, oil decay particles and other harmful impurities. All of these substances adhere to the platinum electrodes, causing the sensor to malfunction.
• Problems with the heating system of the lambda probe. If the heating has ceased to function as needed, then the oxygen sensor will give inaccurate data.
• Overheating of the regulator body. This happens if the ignition timing is incorrectly set.
• Worn out oil scraper rings... In this case, in exhaust pipe falls motor fluid, which acts on the lambda probe.
• If the engine is started repeatedly.
• The use of sealants (especially silicone) for the installation of lambda probes.
• The level of compression in the engine cylinders is violated. In this case, the combustible mixture burns unevenly.
• Clogged petrol injectors in the engine.

If you notice that the lambda probe is not working, the symptoms should not be ignored, as otherwise you will provide yourself with many problems with the car. The fact is that most modern machines, are equipped with an emergency blocking block, which can be triggered at the most unfortunate moment. However, the impossibility of further movement is not the worst thing. If the sensor is depressurized, then the injection system will fail and you will have to pay for expensive repairs of a more serious unit.

Oxygen sensor test

Usually, a lambda probe is diagnosed using a voltmeter and an ohmmeter or multimeter, which replaces both of these testers at once. To check the filament coil of the regulator, it is necessary to disconnect pins 3 and 4 of the connector (usually brown and white wires) from the block and connect the ends of the tester to their terminals. If the resistance of the coil is at least 5 ohms, then this is a good sign.

Also, checking the lambda probe with a multimeter allows you to find out the sensitivity of the oxygen sensor tip. To find out the thermoelectric parameters of an element, it is necessary to turn on and warm up the engine to 70-80 degrees. After that:

• Bring the engine speed to 3000 and hold this indicator for 3 minutes to warm up the sensor.
• Connect the negative probe of the tester (signal wire) to the ground of the car, and the second to the output of the lambda probe.
• Check the tester reading, the data should vary from 0.2 to 1 V and update up to 10 times per second.
• Press the accelerator pedal sharply and release it, if the multimeter shows a value of 1 V, and then drops sharply to zero, then the lambda probe is in order. If the data on the tester does not jump when the pedal is pressed and released, and the readings are about 0.4 - 0.5 V, this indicates the need to replace the sensor.

If there is no voltage at all, then, most likely, the cause of the malfunction lies in the wiring, so "ring" with a multimeter all the wires that go from the ignition switch to the relay.

Healthy! To more accurately clarify the characteristics of the sensitivity of the lambda probe, you will need professional equipment- oscilloscope.

If your car is equipped with a "smart" on-board system, then pay attention to the "Check Engine" signal, which can give the following errors:

• 0130 - indicates that the sensor is giving a wrong signal.
• 0131 - very weak sensor signal.
• 0133 - lambda is responding slowly.
• 0134 - there is no response at all.
• 0135 - malfunction of the lambda heater.
• 0136 - grounding of the second sensor has shorted.
• 0137 - the second sensor gives a very low signal.
• 0138 - too high signal of the second lambda.
• 0140 - probe breakage.
• 1102 - it is impossible to read the indicators, since the resistance of the element is too low or is completely absent.

However, before you check the oxygen sensor lambda probe (video of this process is presented below) using a special tester, pay attention to it appearance... If substances that interfere with its full-fledged work are adhered to it, then it may be possible to limit ourselves to repairing this element.

How to repair a lambda probe

Do-it-yourself repair of a lambda probe is quite simple, for this you need to determine in which node the failure occurred.

If the problem is with the contacts of the circuit, then first of all it is necessary to find the place of the break and check if the contacts are oxidized. The signal may, elementary, not come from the control unit. So check the lambda power supply. If the contacts of the element are oxidized, they must be treated with WD40.

If there is a lot of carbon build-up on the probe body, it may be necessary to clean all parts of the system. And then a logical question arises, how to flush the lambda probe. The fact is that it is strictly forbidden to process platinum electrodes and a ceramic rod with sandpaper. Therefore it is necessary to use specialized means designed to dissolve rust.

To clean the sensor, follow these steps:

• Dismantle the lambda probe, preheating its housing to 50 degrees.
• Remove the protective cap.
• Soak the sensor in phosphoric acid for 30 minutes (it will handle even the most difficult deposits).
• Rinse the lambda in water, dry and reinstall the element. Remember to lubricate the sensor threads special means to create a complete seal (but do not use silicone sealant).

Since the cost of sensors ranges from 1000 - 3000 rubles per element, it is quite reasonable to try to repair the lambda probe with your own hands (see the video below), and only then start installing a new element.

In custody

Vehicle systems are very sensitive and require constant diagnostics and preventive maintenance. In order for lambda probes and other elements to work properly, do not save on good fuel, because most often it is low-quality gasoline that leads to the rapid failure of important working elements.