What is an O2 sensor, and what is its function?

An O2 sensor, also known as an oxygen sensor, plays a critical role in a vehicle's exhaust system. Its primary function is to measure the level of oxygen in the exhaust gases emitted from the engine. This measurement is vital for the engine control unit (ECU) to adjust the air-fuel mixture for optimal combustion efficiency. By detecting the ratio of oxygen in the exhaust, the O2 sensor helps ensure that the engine operates within the ideal range for performance and emissions control, enhancing fuel efficiency and reducing harmful emissions. This sensor is crucial for maintaining the balance in the combustion process and can significantly impact the vehicle's overall performance and compliance with environmental regulations.