Can 02 sensor harm engine if unplugged?

Yes, unplugging the O2 sensor can harm the engine over time. The O2 sensor plays a crucial role in monitoring the exhaust gases and helping the engine control module adjust the air-fuel mixture. Without proper readings, the engine may run rich or lean, leading to increased emissions, reduced fuel efficiency, and potential engine damage due to overheating or excessive carbon buildup. Additionally, it may trigger diagnostic trouble codes and cause the check engine light to illuminate.