Back to all

Making Sense of the O2 Sensor (Oxygen Sensor Replacement)

December 1, 2024

As you know, today’s vehicles rely on a lot of computers in them to keep them running clean and efficiently.  Those computers depend on information delivered by several sensors throughout the engine and exhaust system.  And one of the most important is the oxygen sensor.  

Known as the O2 sensor for short, it looks for too much unburned oxygen that has made it into the exhaust. That signals something isn’t right with the engine’s air-fuel mixture.  The sensor sends signals to the engine’s computers, which can then make adjustments to make sure the engine is running as it was designed to.

Some vehicles can have several O2 sensors, and since they can measure oxygen at various points in the combustion/exhaust process, the computers can pinpoint where the problems lie.  For example, an O2 sensor can detect how much oxygen is coming out of the engine’s combustion chamber, and another one can measure oxygen coming out of the catalytic converter.

As you can see, it’s important that those O2 sensors are working correctly.  If they’re not, the computer is getting bad information.  Garbage in, garbage out. That can result in lousy fuel economy and excess pollution coming out of your tailpipe. It can also affect your vehicle’s performance.  Sometimes your Check Engine light will illuminate when one of your O2 sensors goes bad.  Or you may notice your engine misfiring or idling roughly. 

If you notice any of these symptoms, bring your vehicle on in, and a technician will pinpoint the trouble spot.  

Tuffy Joliet (South Plainfield)
2031 SR 59
Joliet, Illinois 60586
815-436-1829

More articles from Tuffy Joliet

It's (Not) Complicated (Engine Air Filter)

March 29, 2026

While many components of your vehicle are complex and composed of lots of mechanical and electrical parts, there's one that isn't complicated but still important. It's your engine air filter. (And, we should point out, the engine air filter isn't to be confused with the cabin air filter. The ca... More

The Last Gas (Fuel Pump Replacement).

March 22, 2026

You're heading down the road and you notice your vehicle is sputtering, like it's running out of gas. But the gauge show's it's still got a quarter of a tank. So what gives? It could be that your fuel pump is failing, meaning your engine is not getting enough gas to run properly. While fuel pu... More

Don?t Skip Out on These! (Vehicle Maintenance Items You Should Never Postpone)

March 15, 2026

Maybe that little sticker on your windshield is giving you the reminder that its time for your vehicle to have an oil change. Youve thought, Aw, I can skip this one and save myself a little money. When it comes to things you should never ignore on your vehicle, timely oil changes are number one... More