Oxygen sensors provide important data that is used by an engine's computer to adjust the air and fuel used for combustion. When an oxygen sensor fails, the engine operates less efficiently than designed which reduces engine performance.
Oxygen sensors are used to measure the amount of oxygen in the exhaust system. With this information, the engine's computer is able to determine what adjustments are needed for peak performance. Some vehicles use oxygen sensors before and after the catalytic converter to measure the converter performance as well.
Oxygen sensors must be hot to operate properly. Unheated oxygen sensors rely on the exhaust heat for their operation. This means the sensor does not work until the engine has fully warmed up. Heated oxygen sensors use an electrical heating element to heat the sensor, allowing it to work regardless of exhaust temperature.
When a heated oxygen sensor stops working, the engine's computer is unable to precisely adjust the fuel mixture. This causes the engine to not perform efficiently which increases fuel consumption and emissions. If the heating element alone fails, the sensor will not work until the engine fully heats the exhaust.
