Q: What is the Function of an Oxygen Sensor in the Exhaust System?
A: The oxygen sensor in the exhaust system reacts with oxygen to produce a voltage output that varies depending on the oxygen content. This feedback signal is used by the PCM to determine the required fuel injector pulse width and control the air/fuel ratio. The ideal ratio is 14.7:1 for minimum emissions and optimal fuel economy and performance. The post-converter oxygen sensor monitors the efficiency of the Catalytic Converter. The sensor configuration varies depending on the engine model. The PCM operates in an open-loop fuel control mode until the sensor reaches its operating temperature. Proper operation of the sensor depends on electrical connections, air supply, operating temperature, and the use of unleaded fuel. The PCM can detect sensor problems and set diagnostic trouble codes. When replacing the sensor, precautions should be taken to avoid damage or contamination. The sensor should be installed using anti-seize compound on the threads.