Lambda probe: signs of malfunction (Priora, Skoda Octavia, Renault-Megan 2, Ford Focus 2)

This article will tell you what a lambda probe is, and the symptoms of this node's malfunction are also discussed. It is also called an oxygen sensor. It is installed in the exhaust path of an automobile internal combustion engine. And this sensor is put on both petrol and diesel engines.

Basic information about the oxygen sensor

The Lambda probe is similar in principle to its functioning on a galvanic cell consisting of a solid ceramic electrolyte based on zirconium. Doping of the ceramic with yttrium oxide was also carried out. From above there is a thin layer deposition using platinum. It turns out that one electrode perceives the exhaust gas, while the other - the air from the atmosphere. It is through this that the parameters of the gas worked with normal atmospheric air are compared. It is also worth noting that the most effective work is carried out at temperatures above 300 degrees. It is with this heating that the zirconium electrolyte begins to conduct a current. And now it's time to learn about what affects how the lambda probe works. Signs of malfunction "Priora", for example, will allow you to determine even by ear.

The principle of the lambda probe

Due to the fact that there is a difference in the mass content of oxygen, an output voltage appears on the sensor electrodes. To increase the sensitivity of the instrument at a low temperature, for example during engine start-up, forced heating must be used. The electrical spiral is located in the ceramic body of the lambda probe. It has a connection to the vehicle's on-board network. There is also an element of the oxygen sensor, which is based on titanium dioxide. It changes its resistance when the engine is running. It is on this principle that the lambda probe works. The symptoms of VW Golf 3 are the same as in domestic cars.

Oxygen Sensor Operation

At the moment when the engine starts and warms up, the engine operates without data coming from the lambda probe. All correction of the air-fuel mixture occurs according to data obtained from other devices. In particular, they are sensors for the position of the damper in the throttle, engine temperature, and crankshaft speed. The main feature of the lambda probe based on zirconium is that with an insignificant deviation from the norm of the oxygen content, when analyzing the composition of the fuel mixture, a significant change in the output voltage occurs in the range 0.1-0.9 Volts.

Titanium Oxygen Sensors

There are also sensors made of titanium dioxide. Then, when there is a change in the mass fraction of oxygen in the exhaust gases, they gradually change the resistance in volume. Generation of voltage for sensors of this design does not occur. They are much more complicated than zirconium ones, they are used on very expensive cars, for example BMW, Nissan, "Jaguar". On budget cars, titanium-based devices are generally not used, since they have a high cost. On cars of middle and low class, the cheaper zirconium is used by the lambda probe. Signs of a malfunction "Renault-Megan 2" shows those that are no different from those present in domestic cars.

Difference between lambda probes

It is worth noting that the principles of operation of oxygen sensors are the same, do not depend on who the manufacturer is. The only difference is in the dimensions of the housing of these elements. There can also be a slightly different connection, often there is a difference in the connector. All sensors, as mentioned above, have heating or not. Therefore, they differ in the number of wires for connection. According to the materials of the difference, the following are: either zirconium or titanium. In the latter, the heater output always has a red color. There are also types for diesel engines. They are more broadband. You can not install a lambda probe on the gasoline engine. Symptoms of a malfunction (Skoda Octavia is also of interest to many motorists) are accompanied by an error code with a brief description.

Why the lambda probe breaks down

Very often, the cause of premature failure is the poor quality of gasoline. Iron and lead, which can be present in bad gasoline, immediately clog the electrodes from platinum. Consequently, the oxygen sensor fails, it can not normally take all the readings. If the oil-removal rings have a strong production, some amount of oil will enter the exhaust pipe . This also causes a premature failure of the oxygen sensor. Even if you accidentally accidentally got a little solvent or detergent on the oxygen sensor, you can immediately say that it broke down. He does not survive getting such solutions. The destruction of the lambda probe occurs in the case when claps occur in the exhaust system. Ceramics are very fragile, so such sharp blows can destroy it. If the angle of ignition is incorrectly set or if the fuel-air mixture is excessively enriched, the sensor body is heated up strongly. This causes a premature failure.

Less common causes of breakage

Note that when installing the lambda probe, you can not use a variety of sealants that are based on silicone. You can also destroy the lambda probe if you try to start the engine many times, making small pauses between attempts. Provided that the engine does not start. This necessarily leads to the fact that the fuel-air mixture will accumulate in the exhaust system. After a while it will ignite and create a powerful blast wave. Even a poor-quality contact or a short circuit in the output circuit, capable of destroying the device. The total resource of the elements varies in the range of 30..70 thousand kilometers. In many respects it depends on the conditions under which exploitation takes place. The longest service life of the sensors, which have additional heating. Most of the foreign cars are used such a design lambda probe. Symptoms of a malfunction ("Ford Focus 2" or "Skoda" are in your possession) are the same. Therefore, you can diagnose yourself, if you correctly recognize all the symptoms.

Frequent sensor failures

Among the most popular failures, one can note a non-working heating element, as well as a loss of sensitivity. As a result, the speed of the device decreases. Most importantly - try not to replace the lambda probe with any simulators. The electronic control unit will not be able to recognize the foreign signal. Consequently, the correction of the fuel mixture for this simulator will not occur. Please note that in the event that the oxygen sensor has successfully worked in our country (low-quality gasoline), and its service life is already clearly more than three years, then the diagnostician can not even be contacted. At once it is necessary to replace the lambda probe. Signs of malfunction "Skoda" shows clearly when the mileage is over 70 thousand km. Some models of oxygen sensors can have a resource of just over 30 thousand kilometers.

How to determine if the sensor is faulty

If there is an unstable operation of the motor at low revs, it feels as though the engine is "troyting". And thus the expense of gasoline raises, the dynamics of the car worsens. Often you can hear crackling from the catalyst after you muffle the engine. It is also possible to increase (significant) the temperature of the catalyst itself. Sometimes there is such a heating, that the metal simply turns hot. In some cars, the fault can also be judged by the Check Engine warning lamp. Only, unfortunately, not all electronic control systems allow to identify and indicate the malfunction of this element.