When Should the Oxygen Sensor Be Replaced?

Oxygen sensors are not among the maintenance items that need to be replaced regularly, such as oil and air filters, so they typically are replaced only when they fail.

Oxygen sensors are a critical component of the fuel and emissions systems because they monitor the amount of oxygen in the exhaust and transmit that information to the engine computer, which adjusts the air-to-fuel ratio accordingly. If an oxygen sensor fails, the engine computer won’t be able to correctly set the air-fuel ratio, which could result in lower fuel economy, higher emissions and damage to other components, such as an overheated catalytic converter.

No vehicle that we’re aware of has a warning light that signals when an oxygen sensor has failed, so you have to rely on other vital signs to alert you when you have a bad oxygen sensor that you will need to replace, such as the check-engine light on the dashboard illuminating and increased fuel usage.