How does a car behave if the lambda probe does not work? Possible signs of a malfunctioning oxygen sensor

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

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External signs and causes

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

1. The power unit began to operate less stably. The revolutions 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 is not functioning properly, this will cause excessive fuel consumption.
3. The fuel supply has become ineffective, 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, the motor may experience intermittency when operating at idle speed. At maximum - efficiency internal combustion engine operation will also be less low.
5. There were problems with the functioning of electronic systems. Due to the need to repair the sensor, separate compartments power unit will work unstably. This is due to the fact that pulsed fault signals are sent with a delay.
6. While driving vehicle began to twitch. Especially when the car is going uphill.
7. When the engine operates at any speed, popping noises may appear.
8. The engine began to respond slowly to pressing the gas pedal. Acceleration occurs, but not immediately.

One of the important symptoms is the lightning of the Check Engine indicator or the oxygen controller failure light on the car’s dashboard.

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

1. At first, it begins to function unstably. Periodically, the signal from the device disappears, information is provided over a wide range. This leads to deterioration in the quality of the combustible mixture, as well as unstable speed operation. On initial stage The car jerks when moving, popping noises uncharacteristic of internal combustion engine operation occur, and a malfunction indicator may light up on the dashboard.
2. At the next stage, the lambda probe stops functioning on a cold engine until the unit warms up. The symptoms of the problem will be similar, only they will appear with greater force. The engine power of the car may decrease, and a response will appear when you press the gas pedal. As a result, this can lead to overheating of the internal combustion engine.
3. At the third stage oxygen sensor usually fails completely. The power of the power unit drops even more, this is clearly evident when driving at high speed. An unpleasant and pungent odor appears from the muffler.

Reasons that may cause a breakdown of the oxygen sensor:

1. The device casing has depressurized. Because of this, exhaust gases and air began to get inside.
2. Controller overheating. The reason may be due to malfunctions in the ignition system or incorrectly performed tuning of the power unit.
3. Long-term 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, which block its operation. This is usually due to the regular use of low-quality fuel.
5. There is a power failure or the wiring leading to the central control unit is damaged.
6. Mechanical damage to the device. A strong blow to the case may destroy the internal components of the controller. This often occurs during regular off-road driving.

The “Online auto parts store” channel talked 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 cable with 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 has failed and needs to be replaced.

The tester checks like this:

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 sets the measurement limit to 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 throttle change method by 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 that the oxygen sensor is working properly.
5. It is necessary to artificially create a lean mixture situation. To do this, you can create an air leak by slightly loosening the air duct clamp. With a lean mixture, the tester reading should be no more than 0.2 volts.

V_i_t_a_l_y talked about diagnosing the oxygen controller using a multimeter.

Other diagnostic methods

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

You can use an oscilloscope for diagnostics. If the test shows 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 at the signal contact is characterized by greater smoothness, 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. For testing, the controller is removed from the manifold; however, WD-40 or brake fluid cannot be used, since they will get on work surface will cause it to break. If special means are used when unscrewing coked threads, their residues are removed before removing the device.

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

Instructions for repairing and replacing the sensor

You can replace or restore the controller yourself.

How to remove the sensor

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

1. Warm up the surface of the part to approximately 60 degrees. To do this, you can use a regular lighter or torch. 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. It is not recommended to use special tools for dismantling.
4. Remove the protective cap.

Diman Stepanenko spoke about dismantling the lambda probe on his own.

Cleaning and Soaking

There are two options for restoring the oxygen sensor:

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

It must be taken into account that phosphoric acid or another similar product belongs to the category of hazardous substances. When working with a substance, it is important to remember safety rules. Acid should not be allowed to enter the mucous membranes or inside the body.

First way

This method cannot be called accelerated, since the consumer needs to gain 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. Do not use a hacksaw for removal as it will damage the work surface. Dismantling is carried out using a lathe - at the base of the oxygen sensor, you need to cut off the protective cap using a cutter. The cutting is done close to the thread.

If it is not possible to use the machine, you can use a file. It is not possible to completely remove the cap with this tool, but you can make small windows about 5 mm in size on it. Approximately 100 ml of orthophosphoric acid is used for cleaning. If it is not available, you can use a rust converter.

Device recovery:

1. Pour the liquid into a glass container. You can use jars, glasses, etc.
2. Place the oxygen sensor core into the container. The controller cannot be completely immersed in liquid. Wait about twenty minutes.
3. Remove the sensor from the container and rinse its base with tap water. Wait until the device is completely dry.
4. If you are unable to remove the dark deposits 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, high-quality cleaning fails, you can use a brush to enhance the effect of the product. The base of the device is wetted and treated with it. As a result, the plaque should be removed. If the protective cap has been removed, then the brush will not be needed. It is better to use a toothbrush instead.
6. After cleaning has been completely completed, the sensor is washed. If the cap has been removed, then after restoration it must be put back in place. For this, argon welding is used.

When using this method, please note:

1. If the device is heavily soiled, then twenty minutes will not be enough to restore it. For critical blockages, the soaking procedure can be extended to three hours. In some situations, cleaning may take a full night, at least eight hours.
2. After cleaning, you need to check how effectively the procedure was performed. Diagnostics will require some time for the car owner to understand how the car behaves and how much fuel it “eats.” If the malfunction indicator on the device remains lit, 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, you need to soak the device in acid or another product 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 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 lid so that it covers the pipe itself from liquid getting inside.
2. The fire on the burner is lit.
3. The lambda probe core must be dipped in a container of acid, then taken with pliers and heated over a fire. This will cause the acid to boil and the substance will begin to splash. 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 continued until the controller is completely shiny. This may take ten minutes or more. Before further installation, the thread of the lambda probe must be treated with graphite lubricant, which will prevent the oxygen sensor from sticking to the threaded hole.

Installing a lambda probe

Installation of the device is carried out 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 the seat and screwed in.

How to make a corrector (fake) lambda probe?

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

If the catalyst 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 permissible value. The control unit will perceive this event as an emergency and increase the fuel supply to enrich the air-fuel mixture.

When installing such a corrector, exhaust gases will flow through a small hole in the adapter 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 lower. The control module will perceive this as correct work controller and standard catalyst device. The manufacture of blende is carried out using a lathe and a diagram; 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 Internet may not be suitable for making a lambda probe blende for a specific car model; you need to look for a proven option.

Making an electronic controller fake:

1. Using the SprintLayout program and a printer, a layout drawing and arrangement of circuit elements are printed. Printing is done on glossy paper.
2. When sending a file for printing, you must select 100% black for layer K1. In the program, check the box next to Mirror and Scheme Outline. All other layers are deleted.
3. Then the next layer is sent for printing. For the M2 layer, the color is black. The checkbox opposite the Mirror item 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 no less than 1 and no 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. The board is cleaned using fuel or solvent.
7. Then you need to transfer the printout with the tracks 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 as close as possible to the board. As a result, the toner should be reprinted from the foil surface onto the circuit. If the paper density is low, the tracks will be visible. The problem can be corrected using 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 and the elements are soldered.
Connecting all components on the decoy board

What is the price?

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

Video “Installing a mechanical snag of a lambda probe”

The channel “Oil change and other types of maintenance” talked about self-installation mechanical oxygen sensor corrector.

Lambda probe service life at normal conditions operation ranges from 50 to 250 thousand km, depending on the type of sensor.

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

If an error is detected in the operation of the lambda probe, then it is necessary to carry out a full external inspection 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 traces of corrosion on it.

Typical malfunctions of lambda probes, their causes and solutions

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

Poisoning of the sensor sensing element.

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

← Antifreeze poisoning. If contaminated with antifreeze, granular gray or greenish deposits with white streaks appear on the tip:
→ Check the engine cooling system and especially the cylinder head gasket for leaks and carry out repairs. Replace lambda probe.

← Oil poisoning. If the engine consumes excessive oil, gray or black deposits appear on the tip:
→ Check the engine for wear or oil leakage and make repairs. Replace the sensor.

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

← Leaded gasoline poisoning. One or two refills with leaded gasoline will result in shiny, dark gray deposits appearing on the sensor.
→ Replace leaded gasoline with unleaded gasoline and replace the sensor.

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

Burnt out heating element.

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

1. Temperature shock as a result of water entering the sensor due to forcing deep puddles or washing the engine compartment.
2. Faulty electrical wiring.
3. Problems with the catalyst.

→Attention!

If the heating element burns out, the catalyst should be checked, since 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.
→Try to drive through puddles calmly, without splashing, especially if the car has normal ground clearance.

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

. “Crooked” hands of auto mechanics dismantling/installing the sensor while carrying out other work or parts located near the sensor. Damage occurs as a result of the sensor falling onto a hard surface, or something hard and heavy (key, head, part, bolt, etc.) falling onto the sensor or electrical connector.
→ There’s hardly anything you can do to help here, but be careful!

Incorrect laying of the lambda probe cable after reinstallation. As a result, 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 that the wires are laid correctly after installing the sensor.

The exhaust system of the car is gradually being modernized. And this applies not only to the installation of catalysts designed to clean gases from lead and other harmful substances. In addition, modern cars are equipped with an oxygen sensor. People call it a lambda probe. What is an oxygen sensor? Replacement, checking, malfunctions - further in our article.

Characteristic

Not every car enthusiast knows why this element is needed. A lambda probe is a sensor that reads information about exhaust gases and transmits it to the ECU.

The received information is processed in the unit, then the device balances the composition of the fuel-air mixture in order to equalize the order of its combustion in the cylinders.

Where is it installed, types

This element is located in the exhaust manifold (the so-called “spider”), where the exhaust system pipes are connected. In some cases, the sensor is installed closer to the catalyst. But this arrangement does not affect the overall performance of the device. There are several types of oxygen sensors:

• Broadband type.
• With two-channel layout.

The latter were installed on old cars (before the 90s). Modern cars equipped with a broadband lambda probe. Such a sensor is able to accurately detect deviations in the composition of exhaust gases and quickly balance this ratio by reducing or increasing oxygen in the mixture. A working sensor can reduce fuel consumption. Also, its work is aimed at maintaining optimal idle speed.

Why does the oxygen sensor (Kalina) fail?

Signs of a malfunction may vary. First of all, this concerns the quality of the combustible mixture itself. Various deposits can worsen the performance of the oxygen sensor. The element also malfunctions due to depressurization of the housing.

This often happens due to obsolescence of the element. Less often, the housing is damaged mechanically, since it is located in a fairly safe place. Another reason is improper power supply. The sensor contacts may move away, as a result of which information is received incorrectly by the control unit. The composition of the fuel-air mixture is disturbed (too lean or rich). Another cause of malfunctions is an incorrectly set advance angle. This applies to cars with a distributor ignition system. Interruptions can also occur due to problems with high-voltage wires, or due to spark plugs. The engine begins to stall at idle and operate incorrectly at high speeds.

How to identify the problem?

Let's look at possible signs of a malfunctioning oxygen sensor:

• Increased fuel consumption.
• Jerking when moving.
• Noticeable drop in power.
• Unstable engine operation at idle.
• Increased toxicity of exhaust gases.

Note that these symptoms do not always occur specifically because of the oxygen sensor.

Therefore, having identified one of the above symptoms, we proceed to a more detailed check of the device. We'll look at how to do this below.

Detailed diagnostics

How to check There are two ways to do this:

• Visually.
• Using a multimeter.

Let's look at the first method first. So, first we remove the connector from the lambda probe. We examine all contacts. The wires must not be broken or damaged. If the contacts do not fit tightly against each other, this needs to be corrected. Next, we check the oxygen sensor itself. A Priora, the signs of a sensor malfunction may include the presence of soot, must be urgently repaired.

This is due to the combustion of a rich fuel mixture. Because of this, the device becomes dirty and cannot quickly respond to all changes. If there are shiny deposits (this is lead), the oxygen sensor is replaced. Lead damages both the probe itself and the catalyst. What are the signs of a bad oxygen sensor? The presence of lead indicates the use of excess fuel additives or low-quality motor oil.

Diagnostics with a multimeter

How to check with a multimeter? To do this we need to connect the signal wire from the block oxygen probe to our measuring device. Next, we start the engine and keep the speed around 2.5 thousand. Let's release the gas pedal. We pull out the vacuum tube from the fuel regulator and look at the readings of the device.

If the voltage is less than 0.8 V (or absent at all), signs of a malfunction of the oxygen sensor have been confirmed. There is no point in repairing it. Due to the design features, the element can only be replaced. The cost of this element ranges from two to three thousand rubles for VAZ cars. How to change the oxygen sensor yourself, see below.

DIY replacement

First disconnect the terminal on battery. Next, disconnect the block from the sensor itself. Sometimes it is attached using clamps - we also unscrew them. After this, we pick up the “22” or “24” key (depending on the make of the car) and unscrew the probe. Please note that the sensor is part of the exhaust system and, accordingly, operates under extreme load conditions. It is very difficult to unscrew it the first time. Use universal lubricant VD-40. Try not to damage the threads and edges of the stuck sensor itself. As a last resort, you can use a hammer, screwdriver and gas wrench.

With light blows we move the element from side to side. You can pry it out with a screwdriver. If this does not help, use a drill to drill a hole in the probe in place of the nut. We insert a screwdriver inside and try to pull it back out. This should help. We screw a new one in place of the old element. Try to ensure that the part fits snugly against the surface of the exhaust manifold pipe (but do not overtighten the element).

Conclusion

So, we have found out the main signs of a malfunctioning oxygen sensor. The lambda probe is a very small but important element in a car. Its malfunctions can cause serious interruptions in engine operation. Therefore, it is so important to diagnose its breakdown in time.

In engines internal combustion Oxygen determines the optimal ratio of components of the combustible mixture, efficiency and environmental friendliness of engine operation. A lambda (λ) probe is a device for changing the volume of oxygen or its mixture with unburned fuel in the manifold of a power unit. An understanding of the design and operating principle of the sensor will help the car owner monitor its performance, preventing unstable engine operation and excessive fuel consumption.

Purpose and principle of operation of the lambda probe

Lambda probe mounted on the exhaust pipe

Strict environmental requirements for cars force manufacturers to use catalytic converters that reduce exhaust toxicity. But its efficient operation cannot be achieved without controlling the composition of the air-fuel mixture. Such control is carried out by an oxygen sensor, also known as a λ-probe, the operation of which is based on the use feedback device and fuel system with discrete or electronic system injection.

The amount of excess air is measured by determining the residual oxygen in the exhaust gas. To do this, the lambda probe is placed in front of the exhaust manifold catalyst. The sensor signal is processed by the control unit and optimizes the air-fuel mixture, more accurately dosing the fuel supply to the injectors. On some car models, a second device is installed after the catalyst, which makes the preparation of the mixture even more accurate.

The lambda probe works as a galvanic cell with a solid electrode made in the form of ceramics made of zirconium dioxide doped with yttria, on which platinum is deposited, which acts as electrodes. One of them records readings of atmospheric air, and the second - exhaust gas. Effective operation of the device is possible when the temperature reaches more than 300 o C, when the zirconium electrolyte becomes conductive. Output voltage appears from the difference in the amount of oxygen in the atmosphere and exhaust gas.

Oxygen sensor device (lambda probe)

There are two types of λ-probe - broadband and two-point. The first type has higher information content, which allows you to more accurately tune the operation of the engine. The device is made of materials that can withstand elevated temperatures. The operating principle of all types of sensor is the same, and is as follows:

1. Two-point measures the oxygen level in the engine exhaust and atmosphere using electrodes on which the potential difference changes depending on the oxygen level. The signal is received by the engine control unit, after which the fuel supply to the cylinders by the injectors is automatically adjusted.
2. The broadband consists of an injection element and a point-to-point element. A constant voltage of 450 mV is maintained at its electrodes by adjusting the pumping current. A decrease in oxygen content in the exhaust leads to an increase in voltage at the electrodes. After receiving the signal, the control unit creates the necessary current on the injection element to pump or pump out air to bring it to the standard voltage. So, when the fuel-air mixture is excessively rich, the control unit sends a command to pump in an additional portion of air, and when the mixture is lean, it affects the injection system.

Possible causes of lambda probe malfunction

Appearance of a faulty lambda probe

Like any other device, the lambda probe can fail, but in most cases the car remains on the move, while its driving dynamics deteriorate significantly and fuel consumption increases, which is why the vehicle needs urgent repairs. λ-probe failures occur for the following reasons:

1. Mechanical failure due to damage or defect of the housing, violation of the sensor winding, etc.
2. Poor fuel quality, in which iron and lead clog the active electrodes of the device.
3. Oil getting into the exhaust pipe due to poor condition of the oil scraper rings.
4. Contact of solvents, detergents or any other operating liquids on the device.
5. “Popping noises” from the engine due to failures of the ignition system, destroying the fragile ceramic parts of the device.
6. Overheating due to incorrect ignition timing or rich fuel mixture.
7. The use of sealant when installing a device containing silicone or vulcanizing at room temperature.
8. Numerous unsuccessful attempts to start the engine within a short time, which leads to the accumulation of fuel in the exhaust manifold and its ignition, causing a shock wave.
9. Short to ground, poor contact or lack of contact in the input circuit of the device.

Symptoms of a malfunctioning lambda probe

The main malfunctions of the λ-probe are manifested in the following symptoms:

1. Increased overall toxicity of exhaust gases.
2. The engine is unstable at low speeds.
3. There is excessive fuel consumption.
4. When driving, the vehicle's driving dynamics deteriorate.
5. When stopping the car after driving, a characteristic crackling sound is heard from the catalyst in the exhaust manifold.
6. In area catalytic converter the temperature rises or it heats up to a red-hot state.
7. Signal from the “SNESK ENGINE” lamp during a steady state of movement.

Methods for checking a lambda probe

Checking the lambda probe with a multimeter

To check the λ probe yourself, you need digital voltmeter and vehicle owner's manual. The sequence of actions is as follows:

1. The wires are disconnected from the probe block and a voltmeter is connected.
2. The car engine is started, the rotation speed is set to 2500 rpm, and then reduced to 2000 rpm.
3. Remove the vacuum tube from the fuel pressure regulator and record the voltmeter readings.
4. At a value of 0.9 V, the sensor is operational. If the voltmeter does not respond at all, or the reading is below 0.8 V, the λ probe is faulty.
5. To check in dynamics, the probe is connected to the connector, connecting a voltmeter in parallel and maintaining rotation crankshaft engine at 1500 rpm.
6. If the sensor is working properly, the voltmeter will show 0.5 V. Deviation from given value speaks of a breakdown.

Lambda probe repair

If the λ-probe breaks down, it can simply be turned off, and the control unit will switch to average fuel injection parameters. This action will immediately make itself felt in the form increased consumption fuel and the appearance of an error in the engine ECU. If the lambda probe breaks down, it must be replaced. But there are technologies for “revitalizing” a faulty sensor, which make it possible, with a certain degree of probability, to return it to a working state:

Repairing a lambda probe by soaking in phosphoric acid

1. Rinse the device with phosphoric acid at room temperature for 10 minutes. The acid eats away carbon deposits and deposited lead on the rod. It is important not to overdo it, so as not to damage the platinum electrodes. The device is opened by cutting off the cap at the very base on a lathe, and the rod is dipped in acid, then washed in water and the cap is welded in its original place using argon welding. After the procedure, the signal is restored after 1-1.5 hours of engine operation.

Old and new lambda probe

2. “Soft cleaning” of electrodes with an ultrasonic dispersant in an emulsion solution. During the procedure, electrolysis of viscous metals deposited on the surface may occur. Before cleaning, take into account the design of the probe and the material of its manufacture (ceramics or metal ceramics), on which inert materials are applied (zirconium, platinum, barium, etc.). After restoration, the sensor is tested using instruments and returned to the car. The procedure can be repeated many times.

To ensure stable engine operation modern car A wide variety of sensors are used to collect information about the operation of a particular system. Based on their data, the electronic control unit adjusts the quality of the fuel mixture, regulates its quantity entering the combustion chambers, determines the required one, and turns on and off various additional mechanisms.

In this article we will talk about what oxygen is sensor (lambda probe) VAZ-2114, consider its design and principle of operation. In addition, we will try to understand the malfunctions of this element and methods for eliminating them.

What is an oxygen sensor

An oxygen sensor is an electromechanical device designed to determine the quantitative oxygen content in exhaust gases. Its use is mandatory for all cars with an environmental class higher than Euro-2.

Why is it needed? The fact is that modern environmental standards require a car to have a minimum content of harmful compounds in its exhaust. It is possible to achieve their reduction only by forming an ideal (stoichiometric) fuel mixture. It is for these purposes that the oxygen sensor, or, as it is also called, the lambda probe, serves. Electronically receiving information about the oxygen content in the exhaust, it increases or decreases the amount of air to form the mixture.

Where is the oxygen sensor located?

In cars VAZ-2114 lambda probe may be located in different places, depending on the engine modification. In “fourteeners” equipped with one and a half liter power units, it is located on top of the exhaust pipe. You can only get to it from below, by driving the car onto a viewing hole or overpass. In 1.6-liter VAZ-2114 lambda probe much more conveniently located. It is screwed into the top of the exhaust manifold housing. You will immediately see it when you lift the hood.

How does an oxygen sensor work?

U VAZ-2114 lambda probe has a fairly simple design. It is based on a ceramic element with two electrodes. They are usually coated with zirconium dioxide. One of the electrodes is in contact with air (placed outside the exhaust pipes), and the second is in contact with exhaust gases.

The operating principle of the device is based on the potential difference that occurs between the contacts of the device during engine operation. The electronic control unit sends an electrical impulse to the sensor and analyzes its changes. Based on the increase or decrease in voltage at the probe contacts, the ECU “makes a conclusion” about the amount of oxygen in the exhaust.

Lambda probe: signs of malfunction (VAZ-2114)

Failure of the “fourteenth” oxygen sensor is usually accompanied by the following symptoms:

• the “CHECK” warning light lights up on the instrument panel, warning the driver about an error;
• engine operation at idle speed is unstable (the speed fluctuates, the engine periodically stalls);
• a noticeable decrease in the power and traction characteristics of the power unit;
• the car “jerks” when accelerating;
• increased fuel consumption;
• excess level of toxic substances in exhaust gases (determined by measurement at a specialized station).

What can the electronic control unit tell you?

If on dashboard If the warning light comes on, indicating errors in engine operation, and its lighting is accompanied by the above problems, it is advisable to test the controller. Today this can be done as at the station Maintenance, and at home. Of course, if you have a special tester and a laptop (tablet, smartphone) with the appropriate software. When connected, this device will give you codes for possible problems.

In cars VAZ-2114 lambda probe, which is out of order, can declare its malfunction with the following errors:

What can happen to the lambda probe

The lifespan of the lambda probe for the “fourteenth”, declared by the manufacturer, is 80 thousand kilometers. But this does not mean at all that it cannot fail much earlier or last twice as long.

Reason malfunction of the VAZ-2114 lambda probe can be:

• overheating of the working element;
• violation of the tightness of the connection between the sensor and the exhaust manifold body;
• clogging of the device contacts due to the use of low-quality fuel, or oil (coolant) getting into gasoline.

Procedure in case of problems with the lambda probe

If you notice signs of oxygen sensor failure, do not rush to the store to buy a new device. Replacing a VAZ-2114 lambda probe is not such a cheap pleasure. The fact is that this sensor costs about 2.5 thousand rubles. Therefore, first you need to:

• visually inspect the lambda probe;
• establish its modification (in case of purchasing a new one and subsequent replacement);
• check the functionality of the probe.

What kind of lambda probe for VAZ-2114

On the first Samar models of the fourteenth model with one and a half liter engines, Bosch sensors 0 258 005 133 were installed. This lambda probe ensured the operation of the power unit in accordance with the requirements of Euro-2 standards.

Since 2004, VAZ-2114 engines began to be equipped with Bosch sensors 0 258 006 537. They differ from the previous modification by the presence of a heating element. It is noteworthy that all Bosch oxygen sensors for the “fourteenth” are interchangeable.

We check the performance of the oxygen sensor with our own hands

On the VAZ-2114 for performance? Full diagnostics of the device can only be done using an oscilloscope. But it is possible to determine whether it is working or not without complex electronics. To do this, you only need a voltmeter. Connect its “negative” probe to ground, and the “positive” probe to terminal “B” in the sensor connector, without disconnecting it from the on-board network. Turn on the ignition and look at the voltmeter reading. The voltage at the device terminals must match the battery voltage. If it is less, it means there may be a break in the sensor circuit.

If the voltage is okay, check the sensitivity of the working element of the probe. To do this, connect the “negative” probe of the voltmeter to terminal “C” of the sensor, and the “positive” probe to terminal “A”. The voltage should be within 0.45 V. If this indicator is exceeded by more than 0.02 V, the sensor must be replaced.

Repair or replacement

Having determined that the lambda probe of the “fourteenth” is faulty, you can either try to repair it or simply replace it. Restoring the sensor involves cleaning its contacts from carbon deposits. This may be the reason why the device has stopped functioning normally.

To begin, the sensor must be unscrewed from the manifold or exhaust pipe. This is not always easy to do. The fact is that its body very often sticks to the specified elements of the exhaust system. In this case, anti-rust liquid (WD-40 or similar) can help. Treat the joint with this liquid and wait half an hour.

When the sensor is unscrewed, pay attention to its body. It is not removable. The contacts that we have to clean are located behind the slots in the case at the bottom.

Important: do not clean contacts mechanically (knife, sandpaper, file, etc.)! This will only aggravate the situation and permanently disable the sensor.

Contacts should only be cleaned using chemical substances. For example, orthophosphoric acid. Simply place the lower part of the probe in acid for half an hour, and then dry it on a gas burner.

There is no need to disassemble the sensor by sawing its body. As practice shows, after such a procedure, its performance does not return.

If you decide to replace the lambda probe, buy a new device that meets the specifications from a car dealership and install it in place of the old one. With the ignition on, start the engine, warm it up and check if the CHECK warning light is on.

Ways to deceive the electronic control unit

There are three more ways to restore the engine to its former performance without buying a new oxygen sensor. Without a doubt, they were invented by our craftsmen. And they consist in the fact that it is necessary to mislead the electronic control unit so that it does not notice errors in the operation of the sensor.

The first method is mechanical. To implement this, a special spacer (bushing) is screwed in between the lambda probe and the manifold body (intake pipe). Its use allows you to distance the sensor contacts from the exhaust gases. Thus, the amount of oxygen between them artificially increases, and the electronic control unit “remains satisfied” with the result obtained.

A similar VAZ 2114 lambda probe costs about 500 rubles. And if you have a lathe, you can make it yourself.

The next way to deceive the ECU is electronic. Its essence is to install a primitive converter in the sensor circuit, consisting of one resistor (1 MΩ) soldered into the gap in the blue wire of the connector and one capacitor (1 μF) connected between the blue and white wires. As a result of such a simple deception, the electronic control unit will constantly receive a signal of the required voltage and perceive the operation of the lambda probe as proper.

Alternatively, you can also reflash the controller by changing its software. But it is better to entrust such manipulations with the “brain” of the engine to specialists.

How to extend the life of a lambda probe

To ensure that your oxygen sensor lasts as long as possible, do not neglect the following tips:

• use only high-quality fuel;
• do not allow oil and other process liquids to get into the fuel;
• Monitor the operating temperature of the engine, do not allow it to overheat;
• carry out diagnostics of the oxygen sensor in accordance with the schedule of routine maintenance provided by the manufacturer;
• If you identify signs indicating problems with the lambda probe, do not delay diagnosis.