The oxygen sensor monitors exhaust gases to help the engine control unit (ECU) maintain the ideal air-fuel mixture. A faulty sensor can lead to poor fuel economy, rough idling, or increased emissions. Most vehicles have multiple sensors located in the exhaust system, and they typically last 60,000 to 100,000 miles. Signs of failure include a check engine light or decreased performance. Replacing a malfunctioning sensor restores efficient combustion and reduces harmful emissions. The process involves disconnecting the electrical connector and unscrewing the sensor using a specialized socket. Always use a sensor compatible with your vehicle’s make and model. Regular checks during maintenance ensure accurate readings and optimal engine operation.