The lambda probe is an oxygen controller. It is used to control and balance the proportions of air and fuel in the formation combustible mixture. Proper functioning of the element will prevent destabilization of the motor's working process. To determine the cause of the breakdown, you need to know the signs of a malfunction of the lambda probe.

External signs and causes

If the lambda probe heating system or the device itself in the car does not work, the symptoms of the malfunction will be as follows:

1. The power unit began to work less stably. Turnovers can spontaneously increase and fall. The engine often stalls, especially at traffic lights.
2. The quality of the combustible mixture, which is pumped with air into the cylinder system, has decreased. If the sensor has been damaged, this will cause excessive fuel consumption.
3. The fuel supply has become inefficient, the fuel enters the combustion chambers uncontrollably. This can lead to malfunctions in the operation of the unit, as well as the electronic system of the car.
4. Over time, intermittent operation of the motor may occur when operating on idling. At the maximum - efficiency ICE operation will also be less low.
5. There were malfunctions in the functioning electronic systems. Due to the need to repair the sensor, separate compartments power unit will be unstable. This is due to the fact that the impulse signals about the malfunction are given with a delay.
6. While driving vehicle began to twitch. Especially when the car is coming uphill.
7. When the engine is running at any speed, pops may appear.
8. The engine began to slow down to respond to pressing the gas pedal. Acceleration occurs, but not immediately.

One of the important symptoms is the ignition of the Check Engine indicator or the oxygen controller failure light on dashboard auto.

The reasons why the performance of the oxygen sensor will be impaired may not occur immediately, so the failure of the part occurs in several stages:

1. At the first, the oxygen sensor begins to function unstably. Periodically, the signal from the device disappears, information is supplied in a wide range. This leads to a deterioration in the quality of the combustible mixture, as well as precarious work revolutions. At the initial stage, the car twitches when driving, pops uncharacteristic for the operation of the internal combustion engine appear, and the malfunction indicator may light up on the tidy.
2. At the next stage, the lambda probe stops functioning on a cold engine until the unit warms up. Symptoms of malfunctions will be similar, only they appear with greater force. The engine power of the machine may decrease, a response will appear when you press the gas pedal. As a result, this can lead to overheating of the internal combustion engine.
3. In the third stage, the oxygen sensor usually fails completely. The power of the power unit drops even more, this is clearly manifested when driving on high speed. An unpleasant and pungent smell comes out of the muffler.

Causes that may be associated with a breakdown of the oxygen sensor:

1. The case of the device has been depressurized. Because of this, exhaust gases and air began to get inside.
2. Controller overheating. The reason may be related to a malfunction in the ignition system or improper tuning of the power unit.
3. Prolonged exposure to external factors. This reason can be attributed to natural wear and tear, since any oxygen sensor fails over time.
4. The working surface of the oxygen sensor is covered with combustion products that block its operation. This is usually associated with the regular use of low quality fuel.
5. A power failure has occurred or the wiring leading to the central control unit has been damaged.
6. Mechanical damage to the device. A strong blow to the case may destroy the internal elements of the controller. This often manifests itself with regular off-road driving.

The channel "Internet store of auto parts" spoke about the causes of malfunctions in the operation of oxygen controllers.

How to check with a multimeter

Before diagnosing the oxygen sensor itself, its heating device is checked.

The tester can check the operation of the heating component of the oxygen sensor:

1. The diagnostic device switches to the resistance parameter measurement mode.
2. The probes of the device are connected to the heater contacts. These elements are usually made of a cable characterized by a large cross section.
3. The contacts of the heating device are ringing.
4. If the heating element is working, then the resulting resistance value will be less than 10 ohms. If this parameter is higher, then the electric heating device is out of order, it needs to be replaced.

The tester checks as follows:

1. Locate the controller mounting location under the hood of your vehicle.
2. Connect the multimeter probes to the signal outputs of the sensor or electrical circuits. The tester itself is set to a measurement limit of 2 volts.
3. At the next stage, it is necessary to artificially create a situation of an over-enriched combustible mixture. To do this, you can use the method of regassing, periodically pressing the gas pedal. Or you can remove the pressure sensor connector.
4. Then the readings given by the tester are read. Ideally, they should be from 0.8 volts, this indicates the health of the oxygen sensor.
5. It is necessary to artificially create a lean mixture situation. To do this, you can make air leaks by loosening the air duct clamp a little. With a lean mixture, the tester readings should be no more than 0.2 volts.

V_i_t_a_l_y talked about diagnosing an oxygen controller using a multimeter.

Other diagnostic methods

If there are signs of a malfunction of the lambda probe, you can use computer diagnostics. It allows you to monitor the operating parameters of the oxygen sensor online.

For diagnostics, you can use an oscilloscope. If the test showed that the lower limit of the device drops to zero volts, then the controller is working, but it will need to be changed soon. If the time dependence of the voltage on the signal contact is more smooth, then it is time to replace the sensor.

It is correct to start diagnosing four-pin oxygen sensors with a visual inspection; this procedure is recommended to be performed every 10 thousand kilometers. The controller is dismantled from the manifold for testing, and WD-40 or brake fluid must not be used, since their contact with the working surface will lead to its breakdown. If special tools are used when unscrewing the coked thread, their remains are removed before the device is removed.

Evaluate the color as well as the condition of the working area of ​​the oxygen controller. If traces of soot are visible on it, this indicates a re-enriched combustible mixture in the engine. Its presence leads to contamination of the device, therefore, to ensure better performance, soot must be removed. A coating of gray or white indicates the use of additives in engine fluid or fuel. The presence of a shiny coating indicates that the concentration of lead in the fuel used is exceeded. If the plaque is intense, then the sensor cannot be repaired, it must be replaced.

Instructions for repair and replacement of the sensor

With your own hands, you can replace or restore the controller.

How to dismantle the sensor

Removing the device, regardless of the model of the machine, is performed as follows:

1. Warm up the surface of the part to about 60 degrees. To do this, you can use a regular lighter or burner. Warming up will make it easier to remove the device from the seat.
2. Disconnect the wires connected to the part.
3. Carefully unscrew the oxygen sensor. The use of special tools for dismantling is not recommended.
4. Remove the protective cap.

Diman Stepanenko spoke about the self-dismantling of the lambda probe.

Cleaning and soaking

There are two options for restoring the oxygen sensor:

• the first - using phosphoric acid;
• the second - with phosphoric acid and a burner.

It should be noted that phosphoric acid or another similar agent belongs to the category of hazardous substances. When working with a substance, it is important to remember the safety rules. Do not allow acid to enter the mucous membranes or into the body.

First way

This method cannot be called accelerated, since the consumer needs to get full or at least partial access to the ceramic surface of the device. This component is hidden behind a protective cap made of metal, it is not easy to dismantle it. Do not use a hacksaw to remove as it will damage the work surface. Dismantling is carried out using a lathe - at the base of the oxygen sensor, it is necessary to cut off the protective cap with a cutter. The cutting is done next to the thread.

If it is not possible to use the machine, it is allowed to use a file. It will not work to completely remove the cap with this tool, then small windows about 5 mm in size can be made on it. Approximately 100 ml of phosphoric acid is used for cleaning. In its absence, you can use a rust converter.

Device recovery:

1. Pour the liquid into a glass container. You can use jars, glasses, etc.
2. Dip the oxygen sensor core into the container. The controller must not be completely immersed in liquid. Wait about twenty minutes.
3. Remove the sensor from the container, flush its base with tap water. Wait until the device is completely dry.
4. If it was not possible to remove the dark coating on the core the first time, repeat the procedure. It is necessary to ensure that the element again becomes a metallic color.
5. If after several attempts to perform high-quality cleaning did not work, then a brush can be used to enhance the effect of the product. It wets and processes the base of the device. As a result, the plaque should be removed. If the protective cap has been removed, then the brush is not needed. Instead, it is better to use a toothbrush.
6. After the cleaning has been completely completed, the sensor is flushed. If the cap has been dismantled, then after restoration it must be replaced. For this, argon welding is used.

When using this method, please note:

1. If the device is heavily soiled, then twenty minutes to restore it will not be enough. With critical blockages, the soaking procedure can be increased to three hours. In some situations, cleaning can take up to an entire night, at least eight hours.
2. After cleaning, you need to check how effectively the procedure was performed. For diagnostics, it will take some time for the car owner to understand how the car behaves and how much fuel it “eats”. If the malfunction indicator remained on the tidy, then the controller could not be repaired.
3. If the machine is equipped with a sensor whose protective cap is equipped with a double shell, then it will not be possible to make a hole in it with a file. To solve the problem, it is necessary to soak the device in acid or another agent with the cap itself.

The process of cleaning the oxygen controller is shown by Alexander Sabegatulin.

Second way

To restore the controller, you will need the same acid, as well as a gas burner or a stove. When using a household stove, give preference to a small burner.

Cleaning procedure:

1. The lid is removed from the burner. Then it is turned over and installed back, with a slight offset to the side. It is necessary to install the cover so that it closes the pipe itself from the ingress of liquid inside.
2. The fire is lit on the burner.
3. The core of the lambda probe must be dipped into a container with acid, then take it with pliers and heat it over a fire. This will cause the acid to boil, causing the substance to splatter. A greenish tint of salt will appear on the working surface of the device.
4. Wait until the substance has completely boiled away. Rinse the controller with clean water and then repeat the cleaning procedure. These steps must be followed until the controller is completely shiny. This may take ten minutes or more. Before further installation, the lambda probe thread must be treated with graphite grease, which will prevent the oxygen sensor from sticking to the threaded hole.

Installing a lambda probe

The device is mounted in the reverse order:

1. A protective cap is installed on the sensor.
2. Wires are connected to the device.
3. The controller is installed in seat and twists.

How to make a corrector (trick) lambda probe?

There are several types of correctors for oxygen controllers. The mechanical device is the simplest and most affordable in terms of the execution of correctors. It is necessary to carve a special adapter into which a lambda probe is installed, as well as a mini-catalyst. After that, the assembled device is mounted in the regular place of the muffler of the machine.

If the catalytic device or the oxygen sensor installed after it breaks down, a signal will be sent to the control unit. The module will be warned that the exhaust gases contain harmful substances, the volume of which exceeds the allowable value. The control unit will perceive this event as an emergency and will increase the fuel supply to enrich the air-fuel mixture.

When installing such a corrector, exhaust gases will flow through a small adapter hole into the catalyst device. The latter is filled with ceramic dust with a catalytic layer. The concentration of harmful substances in the exhaust gases will be less. The control module will perceive this as the correct operation of the controller and the standard catalyst device. The production of blende is carried out using a lathe and a scheme; steel or bronze can be used as a material.

Scheme of a mechanical corrector for a lambda probe

Universal drawings that can be found on the net may not be suitable for making a snag of a lambda probe for a specific car model, you need to look for a proven option.

Manufacturing electronic blende controller:

1. With the help of the SprintLayout program and the printer, the wiring drawing and the location of the circuit elements are printed. Printing is done on glossy paper.
2. When sending a file for printing, for layer K1, you must select black by 100%. In the program, check the box next to Mirror and Scheme Outline. All other layers are removed.
3. Then the next layer is sent to print. Layer M2 is set to black. The check mark next to the item Mirrored is removed, but it remains opposite the second element. Other layers are removed.
4. When performing the task, it is recommended to use foil textolite. It must be one-sided, and its thickness will be at least 1 and not more than 2 mm.
5. When the printout is in hand, it must be transferred to the LM324 board using an iron. The board itself is cut out taking into account the dimensions, and printouts must be made along its contour. After cutting, attach the diagram to the drawing, the dimensions must match exactly.
6. Using fine-grained sandpaper, the copper layer is cleaned. With the help of fuel or solvent, the board is cleaned.
7. Then, a printout with tracks must be transferred to the working surface of the board. A printed layer of elements is installed on the reverse (copper surface). To do this, foil paper is applied to the board and heated with an iron, the procedure takes no more than 10 minutes. When warming up, the surface of the iron should be pressed to the board as much as possible. As a result, the toner should be reprinted from the foil surface to the circuit. If the paper density is low, then the tracks will show through. The problem can be fixed with a permanent black marker.
8. The next step will be etching, this will require ferric chloride or sodium perchlorate.
9. Then holes are drilled on the board, the elements are soldered.
10. At the final stage, the operating parameters of the corrector are adjusted. To do this, +950 mV is applied to the input, the voltage value is adjusted in the range from 950 to 1000 mV. For the LM324 board, the procedure is done by setting the elements VR3 and VR4.

Connection of all components on the blende board

What is the price?

The cost of the device will be different depending on the manufacturer and brand of the machine.

Video "Installation of a mechanical snag lambda probe"

The channel "Oil change and other types of maintenance" spoke about self installation mechanical corrector of the oxygen sensor.

Many motorists are faced with the problem of increased fuel consumption. This can be due to many engine problems: sensor and actuator failure idle move, ignition problems, compression loss, high pressure pump failure.

But, if fuel consumption has increased significantly (up to 50%), oxygen sensors should be checked immediately, in motorist practice they are often referred to as a “lambda probe”.

What is a lambda probe in a car

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

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

Video - faulty oxygen sensor:

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

Symptoms of an Oxygen Sensor Failure

The main signs of a malfunctioning oxygen sensor include:

• significantly increased fuel consumption;
• uneven engine operation, especially when the accelerator pedal is pressed;
• increased emissions of toxic engine waste;
• catalytic converter malfunctions.

The principle of operation of the lambda probe and the common causes of its failure

The most common cause of lambda probe failure is wear and tear. A typical probe design is shown in the figure:

The weakest points of the design are the ceramic tip and the electric heater. Burnout of the electric heater does not completely disable the sensor.

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

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

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

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

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

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

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

In the diagram: 1 - zirconium dioxide, 2.3 - electrodes (sometimes platinum), 4 - negative ground, 5 - output signal contact. The zirconium oxide probe acquires the properties of a solid electrolyte at a temperature of 300 to 400 degrees Celsius (which is why the probe is preheated). Then the lambda probe starts to register voltage in accordance with the oxygen concentration.

As can be seen from the graph, the dependence has a pronounced stepwise characteristic, which is very beneficial when processing signals using digital methods.

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

• getting inside exhaust system foreign impurities (antifreeze in case of violations of the cylinder head gasket, ether residues when using "quick start" sprays when starting the car, oil with low engine compression, etc.);
• high concentration of lead in fuel;
• cleaning the exhaust system with products not intended for these purposes;
• entry into the exhaust manifold of dust, impurities not removed by the fuel filter.

In many cars, two lambda probes are installed, before and after the catalyst. This makes it possible to control the quality of the mixture with greater accuracy, as well as to check the effectiveness of the catalyst.

How to check a lambda probe with a multimeter and other methods

Checking the performance of four-pin lambda probes installed on most modern cars, it is easier to start with monitoring the performance of the heating element.

To do this, you need to switch the multimeter to the resistance measurement mode and “ring” the outputs of the electric heater. Usually they are made of wire of a larger cross section. The resistance must be less than 10 ohms. If the resistance is greater, this indicates a malfunction of the electric heater.

After 10,000 km of the car, it is advisable to perform a visual check of the probe. To do this, the sensor must be removed from the manifold.

Many use WD sprays for this, or worse, brake fluid. The ingress of these liquids into the working area of ​​​​the lambda probe can lead to its malfunction.

Even if special tools are used to unscrew the coked threaded connection, they should be removed immediately before removing the sensor.

IN working area the sensor should pay attention to its color and condition. The presence of soot (a sign of a rich mixture) leads to contamination of the sensor, soot must be removed for its best performance.

White or gray deposits are evidence of the presence of additives in the oil or fuel, they can also lead to a malfunction of the lambda probe. A shiny coating is a sign of an excess of lead in the fuel. If the buildup is heavy, the sensor must be replaced.

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

In order to check the lambda probe with a multimeter, you need to connect its probes to the signal wires, switch to the measurement limit of 2 Volts. Then, artificially create situations of an enriched mixture, for example, by regassing, or by removing the pressure regulator connector. In this case, the readings of the multimeter should be more than 0.8 Volts, then the probe is working.

Then a lean mixture situation is created (you can artificially create an air leak by unscrewing the air duct clamp). The multimeter should read less than or equal to 0.2 volts.

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

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

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

Oxygen sensor replacement

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

Video - replacing a lambda probe with an Audi A4 B5:

The original lambda probe is usually expensive (up to 6,000 rubles, sometimes more). For some car models, the original sensor cannot be found; it makes no sense to buy from disassembly. In this case, it is better to install a universal lambda probe.

Universal lambda probe

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

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

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

Video - installing a connector on a universal lambda probe:

When installing the sensor, you should pay attention to the tightness of the connection with the collector, the safety of the thread.

Cleaning

Cleaning the lambda probe is an extreme measure. It is done only when there is confidence that the sensor accurately shows the wrong data and the last hope before sending it to the dustbin is cleaning.

The service life of lambda probes under normal operating conditions is from 50 to 250 thousand kilometers, depending on the type of sensor.

The most common reasons for their premature failure are listed below.

If an error in the operation of the lambda probe is detected, then it is necessary to conduct a complete external examination of it and check its operation:

1. Check the integrity of the electrical connector and sensor wires.
2. Carefully inspect the sensor itself for dents, cracks and other mechanical damage.
3. Check the cleanliness of the contact group of the electrical connector, as well as the absence of corrosion marks on it.

Typical malfunctions of lambda probes, their causes and solutions

← If the engine is running normally and the fuel burns out completely, then there is no coating on the working tip of the sensor, and its surface has a dull, matte dark gray color.

Poisoning of the sensitive element of the sensor.

If you observe the following changes on the sensor tip, then you should pay attention to the need for additional repairs.

← Antifreeze poisoning. In case of contamination with antifreeze, granular deposits of gray or greenish color with white streaks appear on the tip:
→ Check the engine cooling system and especially the cylinder head gasket for leaks and repair. Replace lambda probe.

← Oil poisoning. In case of excessive consumption of oil by the engine, deposits of gray or black color appear on the tip:
→ Check engine for wear or oil leakage and repair. Replace sensor.

← Soot poisoning. If the ignition and/or fuel system malfunctions, dark brown or black soot appears on the sensor.
→ Check fuel system, measure toxicity exhaust gases. The sensor will need to be replaced.

← Poisoning with leaded gasoline. One or two refuelings of leaded gasoline will result in dark, shiny deposits on the sensor. gray color.
→ Replace leaded petrol with unleaded petrol and replace the sensor.

← Poisoning by fuel additives. Frequent use of various fuel additives or recent engine repairs using silicone sealants will cause red or white deposits to form on the sensor.
→ Clean the fuel system and engine. Replace sensor.

Burnt out heating element.

If the sensor tip looks quite healthy, its wires and electrical connector are in order, then the sensor failed as a result of the heating element burnout. The heating element could burn out for the following reasons:

1. Temperature shock due to water on the sensor due to forcing deep puddles or washing the engine compartment.
2. Faulty wiring.
3. Problems with the catalyst.

→Attention! If the heating element burns out, the catalyst should be checked, because if problems with the catalyst persist, the new lambda probe will fail again within a short time.

Corrosion of the contact group of the electrical connector.

Water ingress into the electrical connector (on contact group) due to forcing deep puddles or washing the engine compartment.
→Try to pass puddles in a calm mode, without splashing, especially if the car has a normal ground clearance.

Mechanical damage to the sensor, sensor cable, electrical connector.

. "Crooked" hands of auto mechanics dismantling/mounting the sensor during other work or parts located near the sensor. Damage occurs as a result of the sensor falling on a hard surface, something hard and heavy (key, head, part, bolt, etc.) falling on the sensor or electrical connector.
→ There is hardly anything to help, but be vigilant!

Incorrect laying of the lambda probe cable after re-assembly. As a result of this, the cable insulation melts due to its contact with hot parts of the engine, or, in the case of the second sensor, it breaks during movement.
→ Check the correct wiring after installing the sensor.

Replace lambda probe

If the oxygen sensor is faulty, there are several options for solving the problem. One of them is to change the lambda probe sensor. You can do this yourself by buying a new part in a specialized store or car service. Pay attention to the marking that is applied to the old probe. With exactly the same should be a new probe.

If you are not sure that you can handle it, contact the experts. Where can a lambda probe be replaced? In any car service for little money. Experts will do a quality job. The next 50,000-100,000 km, the original oxygen sensor will work perfectly.

• Improves engine performance;

A significant disadvantage of this solution is the price. The cost of a new lambda probe reaches 25,000 rubles. If the car has a disabled or knocked out catalyst, replacing the lambda probe will not help. Software shutdown will help - chip tuning.

Clear lambda probe

Soot often accumulates on the oxygen sensor, and combustion products settle inside. This prevents him from working at full capacity. The car loses traction, decreases maximum speed and increasing fuel consumption. One of the solutions to the problem is cleaning the lambda probe.

1. 
   
2. Orthophosphoric acid cleans the lambda probe in 15-25 minutes. Then rinse the device with warm water and dry thoroughly.

Types of snags on the lambda probe

Disabling lambda probes programmatically using chip tuning will bring nice bonuses:

• Increased power and torque;
• Reduced fuel consumption (compared to emergency mode);
• Improved traction on the bottoms;
• The gas pedal will become more responsive;
• The overall dynamics of the car will improve, acceleration will become more frisky;
• Gear shifts will be smoother;
• The operation of the engine with the air conditioner on is optimized, the car will stop “stupid”.

Software deactivation of lambda probes is carried out by ADACT partners in Russia and the CIS countries.

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Do not drive with a defective oxygen sensor. The car loses dynamics, fuel consumption increases. Therefore, car owners change, clean, install snags or programmatically disable the lambda probe. Which way is better? We analyzed the pros and cons of each.

Replace lambda probe

If the oxygen sensor is faulty, there are several options for solving the problem. One of them is to change the lambda probe sensor. You can do this yourself by buying a new part in a specialized store or car service. Pay attention to the marking that is applied to the old probe. With exactly the same should be a new probe.

Replacement must be done on a cooled engine and the ignition off. To begin with, the wires are disconnected from the old device. Then the old probe is disconnected with a wrench, and a new one is put in its place. You have to be careful not to break the thread.

If you are not sure that you can handle it, contact the experts. Where can a lambda probe be replaced? In any car service for little money. Experts will do a quality job. The next 50,000-100,000 km, the original oxygen sensor will work perfectly.

Benefits of Installing a New Oxygen Sensor

• Saves fuel from 5 to 15%. The deterioration of the sensor affects fuel consumption, so installing a new one will return it to normal;
• Improves engine performance;
• With 100% certainty notifies about the failure of the catalyst;
• Reduces the release of harmful substances.

A significant disadvantage of such a solution is the price. The cost of a new lambda probe reaches 25,000 rubles. If the car has a disabled or knocked out catalyst, replacing the lambda probe will not help. Software shutdown will help - chip tuning.

Clear lambda probe

Soot often accumulates on the oxygen sensor, and combustion products settle inside. This prevents him from working at full capacity. The car loses traction, reduces the maximum speed and increases fuel consumption. One of the solutions to the problem is cleaning the lambda probe.

How to clean an oxygen sensor:

1. Before cleaning the probe, inspect it carefully. If there is damage, or the structure is deformed, then the malfunction is unlikely to be due to contamination. If there is no damage, then the lambda probe can be cleaned.
2. You will need phosphoric acid, which corrodes scale well and cleans soot. Do not use mechanical cleaning tools: iron brush, sandpaper, file, etc. You will damage the precious metal layer and the sensor will become unusable.
   Remove the oxygen sensor from the car and place it in acid. To speed up the process, take a soft brush and apply the liquid evenly over the entire surface.
3. Orthophosphoric acid cleans the lambda probe in 15–25 minutes. Then rinse the device with warm water and dry thoroughly.

Unfortunately, cleaning does not always help.

If orthophosphoric baths did not bring results, the sensor should be replaced or disabled by software.

Install lambda probe

A broken or malfunctioning oxygen sensor cannot be repaired, but can be replaced with an expensive new one or a snag can be installed. Many car owners choose this simple way to deceive the electronic control unit. At the same time, the snag sends an average (similar to a working) signal to the ECU and the computer thinks that everything is fine. In this case, the whole point of the adaptability of the engine disappears. The computer does not understand how well the mixture is prepared and how environmentally friendly the exhaust is. Without a normal sensor, the ECU goes crazy, which leads to increased consumption fuel and other troubles.

Types of snags on the lambda probe

• Mechanical snag on the lambda probe. This universal spare part is installed on almost all cars. Inside it there is a mini-catalyst through which the exhaust gases pass. There they clean up a bit and the electronic unit management receives underestimated values ​​of harmful emissions.
• Electronic snag on the lambda probe. It is specially programmed for a certain brand, volume and year of manufacture of the car, which makes it more expensive than mechanical. Connect the device to the wires through which the values ​​​​are adjusted to acceptable values.

In both cases, the signals from the first and second oxygen sensors will be different. The ECU will take these readings for the normal operation of the catalyst.

Pros and cons of installing a snag lambda probe

Lambda probe snag will extinguish " check engine". The cost, compared to other solutions, is small, so this is the most popular procedure.

A snag on a lambda probe, unlike sensor replacement or chip tuning, does not take into account different parameters and engine operating conditions. For example, adjusting the fuel injection. Therefore, during automatic adjustment, the readings after some time will go beyond the limits of conditionally normal error P0140 will come out again and the check will light up.

Disable lambda probe programmatically

After the physical removal of the catalyst, the software shutdown of the lambda probes after it is a mandatory step. Without adaptation, the second sensor located after the catalyst transmits incorrect exhaust values, the check lights up and the engine goes into emergency mode. This is fraught with increased fuel consumption and poor dynamics.

Considered more economical and much more environmentally friendly. At the same time, the power supply system of such an internal combustion engine has a large number of sensors.

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

If the lambda probe fails, the engine may run unstable, lose power, etc. Next, we will look at 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 how to check an oxygen sensor

Read in this article

Oxygen sensor in a car: purpose and principle of operation

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

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

The general arrangement 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 the release of gases.

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, the specified sensor determines the coefficient of excess air, "sniffing out" the exhaust and fixing the residual oxygen in the composition of the exhaust gases. The main task of the oxygen sensor is to transmit to the engine ECU important information, which allows the controller to determine how efficiently the process of fuel combustion in the cylinders takes place.

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

The main reason for such control is that the most efficient operation of the catalyst is possible only when 14.6–14.8 parts of air and 1 part of fuel are burned in the engine. When burning such a mixture, 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 injection fuel, which constantly receives signals from sensors (including the oxygen sensor).

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

Lambda probe: signs of malfunction

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 they do not work properly, the cylinders and then the exhaust gets motor oil. It can also get into the cylinders, etc. All this leads to the fact that the sensor resource is reduced or the element stops working.

Also, problems with mixture formation or ignition, overheating, short circuits and wiring faults, sensor contamination (including after combustion of gasoline with a high content of additives to increase the octane number) 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 speed floats;
• fuel consumption increases;
• a check is lit on the instrument panel;
• 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 also a second lambda probe, and there may be more sensors. In the first case, the lambda can often be disabled programmatically.

On machines 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 snags of the lambda probe, etc.

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

• Most effective way check is a computer diagnostics of the engine, which allows you to determine errors by the lambda probe. Decryption of errors computer diagnostics engine allows you to localize the problem.
• You can also install a known working sensor on the car. After you need to reset the errors. If the engine is working normally, then the reason is in the oxygen sensor.
• The performance of the lambda probe can also be assessed visually. This visual check will not be accurate, but is sometimes effective. To begin with, the wire connectors are inspected. Everything must be in place and securely fastened.

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

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

• Another way to check is to ring the lambda with a voltmeter tester. To quickly check the lambda probe, the tester is switched to 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. After you need to remove the vacuum tube from the fuel pressure regulator. After that, you can evaluate the tester readings. If the diagnostics and verification of the lambda probe shows 0.8V or less, and there are no indications at all, then it is clear that the lambda probe is faulty.

Also, the test must be repeated by creating a lean mixture. To do this, you need to make an air leak 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

We note right away that the part is officially non-repairable, that is, the lambda probe is not supposed to be repaired and the sensor needs to be changed. However, often the element fails precisely because of carbon deposits on the sensitive element. This element is under a protective cap.

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

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

Oxygen sensor replacement

To begin with, if the car has a heated oxygen sensor, it can often be replaced with an unheated lambda probe. You can also make a reverse replacement with a heated part. Even if the electrical circuit connectors 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 lambda probe must be replaced after the ignition is switched off. It is optimal to buy a lambda probe that has a marking similar to that of the element installed on the machine.

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 screwed new element and wiring is connected;
• the final step is to check the performance of the sensor;

Please note that when unscrewing and tightening the lambda probe, it is important not to strip the thread, that is, no extra effort should be applied.

As you can see, diagnosing lambda problems involves a separate knowledge of what 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 lambda probe voltage should be between 0 and 1 V (taking into account the exhaust temperature of 300–400 degrees Celsius).

Please note that it is under warming conditions that the zirconium electrode gets the opportunity 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-warmed engine.

We also note that if there is such an opportunity, it is better to use an oscilloscope for testing, and not a multimeter. It is the first option that allows you to more accurately assess the quality of the signal. It is also necessary to measure the resistance of the sensor heater. Measurements are first taken with the plug removed, the norm at normal temperature is 2 -14 ohms.

Then the voltage on the heater is measured (with the ignition on, as well as the sensor connector connected). 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 treat the thread with a special mounting paste. In this case, such a paste should not be allowed to get on the protective tube in order to avoid contamination and possible malfunctions of the sensor.

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

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

Given that the sensor takes outside air for comparison with exhaust, where the intake occurs through a connector, such a connector cannot be flooded with contact sprays or lubricated.

Particular care should be taken with. The lambda probe connector must be separately and qualitatively insulated. Even when driving off-road, the sensor can be mechanically damaged or contaminated. To avoid this, you should take into account the features and location of its installation on the machine. As a rule, it allows you to partially protect the lambda as well.

What is the result

As you can see, the oxygen sensor in a car is an important element, on which the quality and composition directly depend. fuel-air mixture. 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 the catalyst to fail, which is much more expensive element than an oxygen sensor.