What Would a Car With a Bad Oxygen Sensor Do?

Updated March 21, 2017

Modern cars are full of a wide variety of sensors ranging from air intake sensors, oxygen sensors, temperature sensors, knock sensors and more. If a sensor is faulty, at the very least you may have a light come on your dashboard. For other sensors, you may experience more serious limitations with your car's performance. Knowing more about your sensors can help to troubleshoot any problems that you are experiencing with your car.

What Does an Oxygen Sensor Do?

The oxygen sensor is one of the main measuring devices used for the fuel control computer to regulate the air mixture with fuel in the combustion chamber. For this reason, oxygen sensors are important components for fuel regulation and consumption.

Signs for Replacing

Losing several miles per gallon in fuel economy can indicate that you may need to replace your oxygen sensor, although there can be multiple other issues surrounding fuel economy as well. If your car's computer indicates a failure code for the oxygen sensor, then the sensor and the wiring should both be tested. If the sensor is bad, then the engine will have decreased power performance and will not respond as quickly. A car may even stall out while driving due to backlogged exhaust systems.


Originally, the oxygen sensor was developed to help reduce harmful emissions caused by automobiles. This happens as the oxygen sensor monitors the level of oxygen in the exhaust so that the computer can regulate the air-fuel mixture during combustion. A car with a bad oxygen sensor can fail many emissions testing procedures, depending on the state in which the driver resides.


If your oxygen sensor goes without replacement in the proper time, that can mean serious damage to your catalytic converter, which will be a costly repair. Catalytic converter malfunctions may also lead to a complete blockage in your exhaust system, leading to other exhaust problems and repairs as well.

When to Replace

Generally, for newer vehicles, the oxygen sensor should be replaced at every 100,000 mile interval. Some cars have a special O2 sensor reminder light that tells you when you need to check your oxygen sensor as well.

Other Factors for Replacing the Oxygen Sensor

Using fuel contaminated with leaded gasoline, however uncommon that is, can cause oxygen sensor failure. Other causes of failure may include phosphorus contamination from excessive oil consumption or silicone from coolant leaks or sprays. Other reasons for failure include environmental factors such as road splash, slat, oil or dirt which can coat the sensor and lead to mechanical stress or failure.

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About the Author

David McGuffin is a writer from Asheville, N.C. and began writing professionally in 2009. He has Bachelor of Arts degrees from the University of North Carolina, Asheville and Montreat College in history and music, and a Bachelor of Science in outdoor education. McGuffin is recognized as an Undergraduate Research Scholar for publishing original research on postmodern music theory and analysis.