Posted on 12/19/2025
When the check engine light comes on, and the car still feels mostly normal, the oxygen sensors are often involved. They sit quietly in the exhaust stream, measuring gases that most drivers never think about, but the engine computer relies on those readings constantly. When a sensor starts to fail, or its signal does not make sense, the computer has no choice but to turn that light on and protect the engine and catalytic converter as best it can. Why Oxygen Sensors Matter More Than Most Drivers Realize Oxygen sensors help the computer decide how much fuel to deliver at any moment. They provide feedback on whether the engine is running rich or lean, so the system can adjust and keep the mixture in a narrow, efficient range. That control affects fuel economy, smoothness, emissions, and catalytic converter life. Without accurate O2 sensor data, the computer is forced into a backup strategy. It uses preprogrammed values instead of live feedback, which keeps the car run ... read more