The oxygen sensor is positioned inside in the exhaust pipe, and it is used to detect rich or lean mixtures. This sensor is an essential component in the emissions control system, and it transmits data to the engine's computer. The primary function of the oxygen sensor is to help the engine operate as smoothly as possible by detecting the appropriate air-to-fuel ratio and using fuel efficiently.
As gasoline is burned inside the engine, a certain amount of oxygen is used to formulate a perfect ratio of air to fuel. When a smaller amount of air is used, fuel is wasted, and this is known as a rich mixture. This type of mixture leaves unburned fuel after the combustion process, which causes pollution. When a larger amount of air is used, there is an excess of oxygen, and this is known as a lean mixture. This type of mixture generates increased amounts of nitrogen oxide pollutants, which leads to engine damage or poor engine performance. The oxygen sensor is used to detect the different mixtures and produce an applicable voltage. The voltage is transmitted to the engine's computer. After determining if the mixture is rich or lean, the device adjusts the amount of fuel that enters the engine. If an oxygen sensor is malfunctioning, the computer is unable to detect the air to fuel ratio, and it simply guesses the perfect ratio. This causes the engine to perform poorly and consume more fuel than required.