Unless you are an automobile mechanic or work around car parts, you probably do not know anything about oxygen sensors. Of course, the name itself gives a pretty big clue, but still leaves a lot to the imagination. The fact is, oxygen sensors are very important to the overall function of a vehicle. The following are what could be referred to as the three W's of oxygen sensors:



What is an Oxygen Sensor?

An oxygen sensor is actually a probe that is mounted inside a vehicle's exhaust. This device is used to measure the ratio of air to fuel inside the exhaust after the combustion process. The sensor sends out voltage information to the engine's computer every few seconds so that it can make adjustments as needed. If there is a perfectly balanced mixture of air and fuel, the output voltage will be around 0.45 volts.

If there is less oxygen in the mixture than needed, it is said to be a rich mixture. The oxygen sensor will report a higher voltage reading of 0.8 volts or above. When the sensor reports a reading of 0.3 volts or below, the mixture is considered to be a lean one. Upon receiving a too high or too low voltage reading, the engine's computer will command the mixture to go either lean or rich, causing it to become balanced again.

Why Replace the Oxygen Sensor?

The function of an oxygen sensor is to measure the air/fuel mixture. It is important that this mixture stay as balanced as possible because it affects the fuel efficiency of the vehicle. The air/fuel mixtures in today's fuel injected vehicles can go back and forth between rich and lean very quickly. Therefore, it is essential for the oxygen sensor to be able to respond appropriately.

Along with better fuel efficiency, having a fully functioning oxygen sensor is good for the environment. A more balanced air/fuel mixture leads to fewer emissions and helps reduce air pollution. If you care at all about the threat of global warming, this should be as great of an incentive for you as getting better gas mileage.

The oxygen sensor can also harm a vehicle's catalytic converter if it is not working properly or has failed. This cannot only cause a decrease in power and gas mileage, but lead to expensive repairs as well.

When Should the Oxygen Sensor be Replaced?

Because emissions from vehicles play such a big role in air pollution, oxygen sensors have become standard equipment. In most vehicles made after the mid 1990s, there is a dash light or check engine light that alerts drivers when their sensor or sensors may not be functioning properly. When this happens, it is best to have the vehicle checked by a mechanic to ensure which sensor (there can be between 1 and 4 sensors) needs to be replaced. For those who do not have a dash light, an emissions test may be necessary. If your vehicle doesn't seem to be performing like it used to, (not as much power or getting worse gas mileage) a faulty oxygen sensor may be to blame.

Depending on where the sensor is located, the replacement procedure can be easy or it could be quite hard. Do-it-yourself mechanics will most likely need to purchase a special socket with a slit in the side for the oxygen sensor wire. Of course, any professional mechanic can perform this procedure as well. Replacing an oxygen sensor will cost somewhere between $50 and $300 but may be well worth the money because of better fuel efficiency.

Conclusion

Hopefully, you now have a better understanding of what an oxygen sensor is, why it is important, and when it needs to be replaced. Pay attention to dash light warnings or other signals your car may be giving you through its performance or lack thereof. A properly functioning vehicle can save you money in the long run, and just might help save the environment.