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

Read a Good Tire Lately? (Tire Wear)

September 14, 2025

There's lots of good information to read in books and online. You might not know that you can also "read" your tires and learn a lot about what shape they're in and if they are in need of attention. It's important to know how your tires are doing because a tire failure can be very dangerous to y... More

Move it or Lose It (Dormant Vehicles)

September 7, 2025

When it comes to your vehicle, driving it too much can cause some issues. But what about not driving a vehicle enough? That has consequences as well. Here are a few things that can happen if a vehicle isn't driven enough. When the engine doesn't operate, the oil isn't lubricating. That means so... More

Always on Guard (TMPS)

August 31, 2025

One of the most important things you can do to keep your vehicle running safely is to make sure your tires are properly inflated. If one or more is vastly over- or underinflated, that has the potential to cause major handling problems and may result in a dangerous accident. All vehicles in recen... More