Possible signs of a malfunction of the oxygen sensor. Oxygen sensor: replacement, check, malfunction

The exhaust system of the car is gradually being modernized. And this concerns not only the installation of catalysts and particulate filters, designed to purify gases from lead and other harmful substances. In addition, modern cars are manned by an oxygen sensor. In the people it is called a lambda probe. What is an oxygen sensor? Replacement, check, faults - later in this article.

Characteristic

Not every car enthusiast knows about what this element is for. The Lambda probe is a sensor that reads out information about the exhaust gases and transfers it to the ECU.

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

Where to set the types

This element is located in the exhaust manifold (the so-called "spider"), where the branch pipes of the exhaust system are connected. In some cases, the sensor is mounted 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 older cars (up to the 90's). Modern machines are equipped with a broadband-type lambda probe. Such a sensor is able to accurately determine the deviations in the composition of exhaust gases and quickly balance this ratio by decreasing or increasing the oxygen in the mixture. A good sensor can reduce fuel consumption. Also, his work is aimed at keeping the optimal speed at idle.

Why does the oxygen sensor fail (Kalina)

Symptoms of the malfunction may be different. First of all, it concerns the quality of the most combustible mixture. Various deposits may aggravate the operation of the oxygen sensor. Also, the element malfunctions due to the depressurization of the housing.

This often happens because of the moral wear of the element. Less often the body is damaged mechanically, since it is located in a fairly safe place. Another reason is improper power supply. The sensor contacts can go away, so the information on the control unit does not arrive correctly. The composition of the fuel-air mixture (too poor or rich) is violated. Another cause of malfunctions is the incorrectly set advance angle. This applies to cars with a tumbler ignition system. Interruptions can occur due to problems with high-voltage wires, or because of candles. The motor starts to triple to idle and does not work correctly at high revs.

How to identify the problem?

Let's consider possible signs of malfunction of the gauge of oxygen:

• Increased fuel consumption.
• Jerks on the move.
• Noticeable drop in power.
• Unstable operation of the motor on idle.
• Excessive toxicity of exhaust gases.

Note that these signs do not always happen precisely because of the oxygen sensor.

Therefore, after identifying one of the above symptoms, we proceed to a more detailed examination of the device. How to do this, consider below.

Detailed diagnostics

How to check the lambda probe (oxygen sensor) with your own hands? There are two ways to do this:

• Visually.
• Using a multimeter.

First consider the first method. So, first remove the connector from the lambda probe. We inspect all contacts. The wires must not be broken or damaged. If the contacts do not fit together tightly, you need to fix this moment. Next, we check the oxygen sensor itself. "Priora", the signs of sensor failure which may be in the presence of soot, should be urgently repaired.

This is due to the combustion of a rich fuel mixture. Because of this, the device becomes dirty and can not react quickly to any changes. In the presence of shiny deposits (this is lead), the oxygen sensor is replaced. The lead damages both the probe itself and the catalyst. What are the signs of a malfunction of the oxygen sensor? The presence of lead indicates the use of excess fuel additives or poor quality motor oil.

Multimeter Diagnosis

How to check a lambda probe (oxygen sensor) with a multimeter? To do this, we need to connect the signal wire from the oxygen probe block to our measuring instrument. Then we start the engine and keep the revolutions around 2,5 thousand. Let's release the gas pedal. Pull the vacuum tube out of the fuel regulator and look at the instrument reading.

If the voltage is less than 0.8 V (or none at all), the oxygen sensor malfunction signs are confirmed. Repair it makes no sense. In view of the structural features, the element is only replaceable. The cost of this element is from two to three thousand rubles for cars brand VAZ. How to change the oxygen sensor yourself, see below.

Self-replacement

First disconnect the battery terminal. Next, detach the shoe from the sensor itself. Sometimes it is attached with clamps - we also unscrew them. After that, we pick up the key "for 22" or "for 24" (depending on the car brand) and twist the probe. Note that the sensor is part of the exhaust system and, accordingly, operates under extreme loads. The first time to unscrew it is very difficult. Use universal lubricant VD-40. Try not to damage the carving and the edges of the very attached sensor. In extreme cases, you can use a hammer, a screwdriver and a gas wrench.

Light strokes move the element from side to side. You can screw it with a screwdriver. If this also did not help, drill a hole in the probe with the drill in place of the nut. We insert a screwdriver inside and try to remove it. This should help. In place of the old element, we twist the new one. Try to keep the part snug against the surface of the exhaust manifold pipe (but do not overtighten the element).

Conclusion

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