Classification and Function of Oxygen Sensors
In modern engines, we can generally see two oxygen sensors, namely the front oxygen sensor and the rear oxygen sensor. The function of the front oxygen sensor is to monitor the oxygen content in the exhaust gas, and then the ECU determines the concentration of the combustible mixture, ultimately adjusting and controlling the fuel injection quantity. The function of the rear oxygen sensor is to monitor the working condition of the three-way catalyst. If the rear oxygen sensor reports a fault, it is generally due to damage to the three-way catalyst.

Working principle of oxygen sensor
At present, the material of oxygen sensors on car engines is mostly zirconia, and the measuring head of the oxygen sensor can monitor the oxygen content in the exhaust gas. This includes two situations, one is when the combustible mixture is rich; Another type is a lean combustible mixture. In any case, the oxygen content in the exhaust gas should be lower than that in the atmosphere, and there will be a difference in the concentration of oxygen ions at the inner and outer ends of the zirconia probe. That is to say, there are fewer oxygen ions in contact with the exhaust gas, while there are more oxygen ions in the zirconia part in contact with the air through the oxygen sensor sleeve. The concentration difference of oxygen ions on both sides will generate an electromotive force in zirconia. This electromotive force is the signal of the oxygen sensor.
When the concentration of the mixed gas is high and the oxygen content in the exhaust gas is basically zero, the concentration difference of oxygen ions generated inside and outside the oxygen sensor is large, resulting in a large induced electromotive force and strong signal. On the contrary, when the mixture is too lean, the oxygen content in the exhaust gas is higher than that in the rich mixture, so the difference in oxygen ion concentration between the inside and outside is small, and the induced electromotive force is small. Therefore, the ECU will judge the concentration of the mixture based on the strength of the oxygen sensor signal.

What are the impacts of damaged oxygen sensors
There are two types of damage to the oxygen sensor, one is caused by its own reasons; Another reason is that external factors cause damage to the oxygen sensor. The damage to the oxygen sensor caused by its own reasons is due to the aging of the oxygen sensor, which leads to damage or poor operation of the internal heating device, resulting in signal distortion. External factors are often caused by poor fuel quality and excessive harmful substances. So what impact will a damaged oxygen sensor have on your car?
1、After the oxygen sensor is damaged, it can cause the ECU to control the fuel injection quantity incorrectly, and in severe cases, it may lead to severe carbon buildup in the engine, especially in the fuel injectors.
2、Damage to the oxygen sensor can cause the pressure of the fuel injector to be too high, and over time, it can lead to fuel injector leakage and damage.
3、The operation of the three-way catalyst is affected, and after the oxygen sensor is damaged, the concentration of combustible mixture is likely to increase. At this time, the amount of exhaust gas increases, which increases the working pressure of the three-way catalyst and ultimately leads to its damage.