Do you have problems with oxygen sensor?

What is an oxygen sensor?

The oxygen sensor in a car is another important component. Its main task is to check the oxygen level in the exhaust gases and transmit the information to the power unit control module.

Now that we have covered the basics of "what does an oxygen sensor do in a car," let's delve into the details of its structure.

This component of every car is a small electrochemical sensor (4 to 8 cm). The sensor consists of a housing, a protective screen through which the gas mixture passes, ceramic and heating elements, electrodes, an air channel, a conductor, and an insulator. The ceramic element is an alloy of zirconium dioxide coated with electrodes and platinum, which produces an electrical signal in response to the oxygen level. The heating element helps the sensor reach its operating temperature faster. Signals are transmitted to the ECU via conductors and a connector. Modern cars are most often equipped with two such sensors, and sometimes even more. In this case, one sensor is located before the catalytic converter and the other after it.

How does an O2 sensor work?

When fuel is burned, oxygen concentration plays an important role in engine efficiency. So, what is an O2 sensor in a car? The amount of oxygen in the fuel-air mixture indicates whether the concentration of components is correct when they are fed into the combustion chambers. Too much oxygen indicates that the mixture is lean; too little oxygen indicates that the mixture is rich. When the onboard computer detects either of these scenarios, it adjusts the amount of fuel supplied accordingly.

If there are two sensors in the car, the one located in front of the catalytic converter sends a signal to the ECU, which adjusts the fuel supply to achieve optimal performance. The second sensor monitors the catalytic converter and, in case of malfunction, also sends a signal to the ECU similar to the first one. Thus, the ECU detects the error and the Check Engine light illuminates on the dashboard.

A faulty oxygen sensor in a car tells the PCM to add or reduce the amount of fuel when it is not necessary, which can cause certain problems.

The most common cause is dirty contacts. We have already written about why it is important to clean electronic sensors, and we recommend that you read this article.

There are several dirty oxygen sensor symptoms:

• The "Check Engine" light is on. Of course, the "Check Engine" light can come on for many reasons, so you should check your car immediately. A faulty oxygen sensor is a common cause of this.
• High fuel consumption. One of the most unpleasant symptoms for every driver. Have you noticed high fuel consumption? This may be the result of a faulty oxygen sensor.
• Black smoke from the exhaust pipe and an unpleasant rotten egg smell from unburned fuel.

Replacing the O2 sensor

In fact, a faulty oxygen sensor is a serious problem that should be addressed as soon as possible. Most zirconium O₂ sensors last 60,000–150,000 km. The higher the quality of the sensor, the longer it will last, which is why there is such a large gap. Operating conditions have a significant impact: poor-quality fuel, overheating of the exhaust system, oil or antifreeze leaks shorten the service life.

Is it possible to replace a faulty sensor yourself? In fact, yes, but this process requires certain knowledge and special tools. Also, after replacement, you need to clear the errors with an OBD-II scanner so that the ECU can update the lambda sensor readings and reset the previous errors. You can use inCarDoc for this.

How to use the InCarDoc app to monitor harmful emissions

You can save time and money with InCarDoc. This app helps you perform comprehensive vehicle diagnostics and detect malfunctions in the catalytic converter, O2 sensor, engine, and other systems in a timely manner.  

The app offers recording and viewing of dynamic engine parameters and a special economizer widget that records fuel consumption on the route. Thus, using inCarDoc for OBD2 diagnostics is the way to efficient car operation.