Back to all

Making Sense of the O2 Sensor (Oxygen Sensor Replacement)

August 18, 2025

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.  

Car Fix Waukegan
119 South Green Bay Road
Waukegan, IL 60085
8478738403
http://carfixwaukegan.com

Need Service?

Request a Quote

More articles from Car Fix - Waukegan

Refresh Your Brakes (Brake Fluid Exchange)

May 3, 2026

Brakes are one of your vehicle's most important safety components, and you may have noticed that they don't stop as surely as they used to. Maybe it takes you applying a little more pressure to them than before, or perhaps you get the feeling that they're not stopping you as quickly. Those coul... More

Differential Service

April 26, 2026

When you're driving and turn a corner, you probably aren't aware of all that's going on with your wheels. The outside wheels have a longer distance to travel than the inside wheels, so there are gears that allow the wheels to go at different speeds when you turn. That set of gears is called a ... More

Busting Automotive Myths in Waukegan, IL

April 19, 2026

Myths passed around our Waukegan, IL community start with a grain of evidence and are then built up with a lot of imagination and very elastic logic. And the internet is a breeding ground for automotive myths. Some bloggers recall the vehicles of yesteryear and declare their modern decedents to... More