Damaged lambda sensor – symptoms

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Damaged lambda sensor - symptoms

When it was first used for general use, it was the nineties of the twentieth century. At that time, the world began to pay more attention to the environment, and thus to the quality and quantity of car exhaust. The lambda probe was supposed to be a solution to solve the problem. The innovative solution was a source of pride for producers. Especially who emphasized their pro-ecological approach by placing appropriate markings on cars, indicating the presence of a probe. For car users, all this sounded very mysterious, modern and attracted attention. What is this? What is its operation and why it fails from time to time? Damaged lambda sensor – do you know all the symptoms?

A bit of history, or how it started?

A specific solution was created in 1979. However, widespread use took place only in the nineties of the twentieth century. In the initial period, the lambda probe was used only in gasoline engines. Today it has changed. Due to extremely restrictive combustion standards, several probes are used in diesel and also diesel engines.

What lambda sensor is it and what is it for?

It is an electric sensor that is located in the exhaust system, and more specifically in the exhaust pipe in front of the catalytic converter. The task of the probe is to measure the composition of exhaust gases that come out of the engine compartment.


Internal combustion engines require a mixture of air and fuel that, in simple terms, “explodes” in the engine compartment and contributes to driving the vehicle. The purpose of the probes is also to monitor the amount of air that has not been consumed in the exhaust gases emitted from the engine. The collected information is transferred to the control computer. It on this basis selects the correct composition of the fuel-air mixture.

There should be a mixture in the engine compartment characterized by a strictly calculated ratio, which is 1 (fuel): 14.7 (air). Such a ratio ensures optimal combustion of fuel and, consequently, proper engine operation. It also reduces the amount of harmful substances that enter the atmosphere, including exhaust gases. Incorrectly selected mixture not only affects the quality of exhaust gases, but also can cause engine failure.

Why is the lambda sensor failing?

Damage to a particular device occurs under extreme conditions. Due to the fact that it is located in the middle of the exhaust system, as well as the exhaust system, it is affected by very high temperatures exceeding 300 degrees Celsius. What’s more, such elements as water, road salt, dust that escape from the outside also have an unfavourable effect. According to estimates, the probe is able to survive mostly on a mileage of about 50-100 thousand kilometres. However, the good condition of the engine and the refuelling of high quality fuel can contribute to a significant extension of the life of the device. 

Symptoms of damaged lambda sensor

Among the symptoms informing about the damage of the probe, the increase of combustion, which may even exceed 50%, is mentioned first. Another symptom that can be felt by the driver is uneven engine operation. Damaged lambda sensor can be indicated by a red indicator light, which is activated on the dashboard of the car. Sometimes the failure of the device can be assessed on the basis of a coloured film appearing on the probe. The colour observed may indicate the likely cause of the abnormality. And so when we notice the colour:

    • red – we can suspect the presence of harmful elements in the fuel,

    • dark brown – then we get information about too rich air-fuel mixture,

    • green – we know about the leakage of refrigerant fluid,

    • black and greasy – we are alerted to excessive oil consumption.

Damage to the lambda probe can also be caused by irregularities in mechanical failure of its structure. For example, fusion of cables, bending, corrosion of styles or loosening of gaskets.

Repair of damaged lambda sensor

The repair should be carried out by a mechanic. In modern cars, access to the lambda probe may not be easy. In order to disassemble and replace a damaged device, many elements must be used. An important issue is also the removal of control computer errors. This can not be done without a specialized device.

A malfunctioning probe can not be ignored. Failure to take corrective action may involve high costs. It contributes to greater combustion, which is particularly severe when moving around the city. Failure to repair can also damage the particle filter. That is why it is so important not to ignore any symptoms that indicate a lambda probe failure.