Reasons for the failure of the oxygen sensor. What to do with a non-working lambda probe

Models of lambda probes are special samples of an oxygen sensor, which is necessary for the correct operation of the electronic system in the fuel combustion chambers. Thanks to this element, the system manages to balance and constantly monitor the percentage ratio between oxygen and gasoline. With the help of a probe, the electronic system constantly corrects the structure of the fuel mixture supplied to the engine, and also warns of destabilization in the engine's working process.

When operating this fragile device in very aggressive environments, it gradually wears out and requires replacement after two years of use. By replacing the lambda probe, you can avoid engine damage. With a periodic check of the lambda probe, you will have a real guarantor of the stable operation of your car.

How does a lambda probe work?

The main purpose of the sensor is to timely determine the chemical composition of the exhaust gas and determine the level of the percentage of oxygen in it. In order to avoid problems in the operation of the engine, this indicator must be kept in the range of 0.1-0.3%.

Types of lambda probes

Now on the automotive equipment market, you can increasingly find only 2 variations of the device:

The probe is based on a two-channel layout type. This type of sensor was mainly used in cars from the 80s, and is also used in modern economy class cars.
Wideband lambda sensor. This type of probe is used as standard in 70% of middle and upper class machines. This type of sensor not only accurately determines any deviations from the norm between the elements, but also informs the system in a timely manner for instant position stabilization.

All samples of modern lambda probes are mounted in a special exhaust manifold, where the hoses and pipes are connected directly. This positioning of the sensor allows you to get the maximum performance and accuracy of this instrument.

The main task of any lambda probe is to significantly increase the working resources of the car by reducing fuel consumption and increasing the stability of maintaining speed during idle. As a result, this sensor does not give specific values of the parameters of the fuel mixture, but reacts only when the obtained values are destabilized. After detecting a discrepancy with the set parameters, the sensor transmits information to the central unit, which corrects the fuel-air ratio.

Advice: if it was made by you or by another car, be sure to check the correct operation of the probe. If this part is replaced, the correct operation of the device may be impaired.

The main symptoms of a lambda probe malfunction

Among the signs that make it possible to determine in advance whether the probe is working properly or not, the following are distinguished:

The appearance of instability when the engine is running (the engine starts to pick up speed abruptly and also stalls abruptly);
Deterioration of the quality of the fuel mixture pumped into the cylinder system (this leads to excessive consumption of fuel);
Uncontrolled and ineffective fuel supply (the appearance of malfunctions in the operation of the engine and the electronic system of the machine);
The gradual appearance of intermittent engine idling;
Decrease in the efficiency of the engine at maximum speed;
Problems in the operation of electronic systems (malfunctions in the sensor lead to unstable operation of the engine compartments, since the signal about the malfunction is transmitted with a delay);
The presence of periodic "twitching" of the car;
The appearance of incomprehensible pops when the engine is running;
Untimely (delayed) response of vehicle engine systems to pressing the accelerator pedal;
The appearance of a constantly flashing light on the sensor malfunction on the central instrument panel.

In the event that you find one or more of the indicated reasons for your vehicle, you should consider replacing this device.

Advice: One of the main indicators that the lambda probe is completely out of order is a constant sharp drop in engine power when accelerating.

Repair or replace the lambda probe?

As well as the repair of the lambda sensor should be carried out in a car service. However, in most cases, this spare part is completely replaced, since it simply cannot be repaired further. The problem is the high cost of original sensors from an authorized dealer.

As a result, most motorists decide to switch to using a universal sensor, which is suitable for almost any brand of car and is much cheaper than its native counterparts. In addition, if you want to save money, you can purchase a lambda probe from a showdown. Used sensors are shown there, however they may have an extended warranty period. You can also immediately purchase a full-fledged model of the exhaust manifold, in which the lambda probe is already installed.

If the problem lies only in the presence of a small error in the operation of the sensor, you can quickly repair it yourself. The main signs of a malfunction are associated with its strong pollution during the settling of fuel combustion products. In order to understand whether the probe has affected the operation or not, it is enough just to show it to the specialists at the auto center. After experts confirm the fact that the lambda probe you removed is working, you just have to carefully clean it from dust and burnt deposits, and then put it back.

DIY lambda sensor repair steps

To dismantle the lambda probe, it will be necessary to first warm up its surface to the limit of 60 degrees. Then carefully remove it and additionally take out the protective cap. After that, you can start cleaning with phosphoric acid, which helps to easily cope with any (even the most persistent) combustible deposits.

Advice: at the end of work, before installation, do not forget to pre-lubricate the threads with a special sealant to ensure complete tightness of the product.

Video: how to check a lambda probe?

A lambda probe is an oxygen sensor. The Greek lambda in mechanical engineering means the ratio of excess air in the fuel-air system. A breakdown of this device can have extremely negative consequences for the engine and the entire vehicle. Therefore, it is very important to know how to determine the malfunction of the lambda probe.

The purpose

The lambda probe measures the amount of oxygen in the residual gases. The collected data is transferred to the engine ECU. This allows you to determine the nature of fuel combustion. Without this, stable operation of the catalytic converter is impossible.

The catalyst efficiency window is very small. Therefore, it is so important to identify the signs of a malfunction of the lambda probe in advance. After all, it is this device that is responsible for monitoring the exhaust tract.

Important! The device is only available in systems with electronic injection.

To understand why the lambda probe broke, you need to understand a little about its design. It is installed in the exhaust tract, close to the catalyst. If the system meets the Euro 3 standard, then there must be another device at the output.

Diagnostics

Attention! To determine most of the symptoms of a lambda probe malfunction, high-quality technical diagnostics are required. It is recommended to check it once every 30 thousand kilometers.

The main indicator of a malfunctioning lambda probe is an incorrect output voltage. At idle at 2000 rpm. This indicator should be in the range from 0 to 1 V.

To measure the residual oxygen in the used gases, the temperature must be 300-400 degrees. At this temperature, the zirconium electrolyte acquires conductivity. The difference between atmospheric oxygen and oxygen in the exhaust pipe leads to the appearance of a voltage at the electrodes of the lambda probe.

Therefore, to check for faults, diagnostics are carried out with the engine running. All measurements are carried out using a multimeter or oscilloscope.

At the end of the troubleshooting procedure, the resistance of the sensor heater is measured. Disconnect the plug before checking. Standard from 2 to 14 ohms. Usually the manufacturer sets the standards for his lambda probes himself. Voltage is also checked. The recommended indicator is 10, 5 V.

Attention! A lower reading indicates a malfunction. Checking the battery voltage, connection and cable voltage can help.

Malfunction symptoms

There are certain symptoms that make it possible to determine in advance the malfunction of the lambda probe. If your engine stops working stably, the sensor may be the cause.

If the lambda probe is faulty, the quality of the pumped fuel mixture deteriorates. Feeding becomes uncontrolled and ineffective. Typically, the recovery of the device from normal operating mode occurs gradually. As a result, it is extremely difficult to notice a malfunction in the early stages of the process.

Any serious lambda probe malfunction begins with an unstable signal transmission to certain engine compartments. Naturally, idling goes wrong.

The revolutions fluctuate in a fairly wide range, which leads to a decrease in the quality of the fuel system and the efficiency of the entire engine. One of the signs of serious damage to the lambda probe is the constant "jerking" of the car.

Incomprehensible pops are heard when the engine is running. A light on the instrument panel flashes constantly, signaling a malfunction of the lambda probe. The complex of these phenomena clearly demonstrates that something is wrong with the sensor. If nothing is done now, then soon the device will completely fail.

Attention! An important bell and a sign of a serious malfunction is a drop in power.

The next stage of the lambda probe malfunction is the final breakdown. In addition to the drop in power, there is a slow response of the system when the accelerator pedal is pressed. Pops are constantly heard from under the hood. The car "jerks".

Attention! Another important symptom of a malfunctioning lambda probe is engine overheating.

What happens if you ignore the symptoms of a malfunction?

Naturally, every driver is interested in what the malfunction of the lambda probe affects. Most often, when a given part fails, the following consequences can be observed:

The vehicle is moving unnaturally.
Fuel consumption increases significantly.
An unpleasant, pungent odor is generated from the exhaust pipe.

In modern cars with electronic filling, in the event of a breakdown of the lambda probe, emergency blocking is immediately activated. This allows you to save the car from serious damage, even if the driver did not notice any signs of a malfunction. In addition, driving with a broken lambda probe is simply unsafe.

The car is behaving too unpredictably. Because of this, an emergency situation on the road may arise, which will endanger not only the life of the driver, but also the lives of other people. That is why it is so important to notice the signs of a malfunction in time and send the car to the service. Moreover, for greater safety, it is better to call a tow truck.

In the worst case scenario, the sensor is depressurized. In such a case, further movement may damage the engine. For restoration, at least major repairs will be required.

When depressurization occurs, exhaust gases enter the intake duct. When braking, the lambda probe begins to fix a huge number of oxygen molecules. As a result, the injection system completely fails.

The main symptom of such a malfunction is power loss. This is best seen at high speeds. At the same time, mechanical tapping under the hood is constantly heard. Bad smell and tugs are also present.

Advice! In order to be sure of a malfunction of the lambda probe, open the hood and inspect the valves. A sign of breakage will be sediment from soot formations.

Causes

It is best not to troubleshoot vehicle malfunctions, rather than let them occur. There are a number of reasons that can lead to a breakdown of the lambda probe, the main ones are:

Bad gasoline. Excess impurities clog the platinum electrodes.
The unsatisfactory condition of the oil scraper rings.
Vehicle hit in an accident.
Contact with the ceramic tip with solvents or antifreeze.
Overheating of the lambda probe housing. This is due to an incorrectly set ignition timing.
Bad contact of the output circuit of the sensor.
Malfunctions in the ignition system.
Repeated attempts to start the engine with short rest periods. This causes unburned fuel to build up in the exhaust pipe and can ignite.

Important! Under no circumstances should sealants be used when installing the lambda probe, which tend to cure. Also, they should not contain silicone.

The sensor resource is on average estimated at 30-70 thousand kilometers. Much depends on the manufacturer and the operating conditions of the vehicle. That is why it is so important to know the signs of possible breakdown. This information will help you to always be on the alert and prevent more serious malfunctions.

According to statistics, heated lambda probes have a longer service life. It is not surprising that the main symptom of a malfunction of such a device is the inoperative heating. Also performance decreases.

Advice! If you notice any of the above, use an oscilloscope to confirm. The device can be bought for 4000-5000 rubles.

Buying an oscilloscope allows you to save your car from a malfunction of the lambda probe and costly repairs. If you do not want to do the diagnostics yourself, just take the car to the service, the check procedure will not take much time.

Lambda probe malfunctions in the "Lada" Kalina

Unfortunately, the domestic car has already become famous due to the many malfunctions of the lambda probe. The signs of breakage are no different from the standard ones, but the reasons are largely due to a not entirely practical design.

Important! In most cases, the heating element breaks in the Kalina lambda probe. In addition, water, dirt or grease often gets on the sensor, which also leads to a malfunction.

If, while driving, you notice the symptoms of a malfunction described in the previous sections. There is a simple and reliable way to check the Kalina lambda probe without additional equipment. Just turn off the ignition, disconnect the harness connector and check contact X1 / C4. If there is no short circuit with the on-board network, the device is faulty.

Outcomes

Knowing the signs of a malfunction of the lambda probe will allow you to diagnose the breakdown in time and take all the necessary actions to quickly restore the vehicle's performance.

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, therefore the driver should always take care of regulator diagnostics. From this material, you will learn what the lambda probe has signs of malfunction, 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 a particular 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:

Use of low quality fuel. If the fuel contains iron, water, decomposition 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.
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 in 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.
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.
If the condition of the oil scraper rings is poor, doing so could cause engine fluid to enter the exhaust pipe. Accordingly, its effect on the sensor can be destructive and there will be a need to repair or replace the device.
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 ceramics of the device.
Shocks appear in the intake manifold of the motor.
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 at short intervals. As a result, unburned fuel builds up in the engine exhaust manifold. When a shock wave occurs, the fuel can ignite.
Contact with the ceramic element of various consumables- solvents, coolants, detergents, etc., may necessitate regulator repair.
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.
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.
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.
The compression level in the engine cylinders is incorrect. If the compression is uneven, it can lead to unbalanced combustion of the combustible mixture.
When installing the timing belt, the device marks were incorrectly set, or else they could be violated during the operation of the vehicle.
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 the signs of a breakdown. But if you familiarize yourself with the signs described below, then you will not have any problems during the check.

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

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.
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 notice 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 don't have a multimeter, contact an electrician for help.
The next step, by which you can check the malfunction, is the 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 the gas pedal is pressed, a slower reaction of the car will be felt. The same pops will be heard from under the hood, the car will twitch while driving - these signs of malfunction indicate that it is necessary to repair and restore the device.
One of the most dangerous signs of a malfunction is motor overheating.
Also, an 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.
If you have a modern car, then as a result of a breakdown of the device, the emergency blocking 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.
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 takes place, the exhaust gases do not escape 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 be completely damaged. If the regulator is depressurized, this can be learned as a result of power loss, which is especially felt when driving fast. Jerks and pops, as well as an unpleasant smell - the same symptoms of breakage. You can also check the body of the exhaust valves and the installation location of the plugs - 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:

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 fix in memory an error indicating the failure of the lambda probe heater.
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.
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 ECU 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 storage 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 ECU. 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:

To properly remove the device, warm up the engine a little and turn off the ignition.
All wires are disconnected from the device.
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.
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, so you don't need to put in a lot of effort. To ensure the tightness of the device, it can be treated with a sealant before installation.
Replace all wires.

Video "How to correctly change the lambda probe"

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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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 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. 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 air-fuel 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 amount of oxygen decreases, the ECU receives a more correct value of the indicator) and electronic(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 operates normally, 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 nominal 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 come from under the hood; the indicator on the dashboard is on; engine power decreases and the accelerator pedal operates more slowly; a pungent 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 about this. He brings the composition of the mixture back to normal by decreasing or increasing the volume of the 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 air-fuel mixture.

What is snag 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 working catalyst.
Electronic... This is a more complex microprocessor-based device. This is how the blende of an electronic 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 concentration of the fuel 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 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.

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) is 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 consumption of gasoline, increased engine load, and breakdown.

The oxygen sensor in some cars is located just 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 a 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 a 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 will be replacing the sensor completely or removing 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 odor appears from the exhaust pipe than before;

the motor is overheating.

From these changes, it is not difficult 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 exhaust toxicity. You need to regularly check it with a specialist, monitor the quality of the 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:

Didn't find the answer to your question? Find out, how to solve your particular problem - call right now by phone:

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

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

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

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Oxygen sensor in a car: purpose and principle of operation

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

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

The general structure of the lambda probe is as follows:

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

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

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

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

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

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

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

Lambda Sensor: Symptoms of Malfunctions

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

How to clean a lambda probe

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

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

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

Replacing the oxygen sensor

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

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

The replacement itself is performed as follows:

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

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

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

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

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

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

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

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

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

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

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

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

What is the bottom line

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

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