Back to all

Making Sense of the O2 Sensor (Oxygen Sensor Replacement)

November 30, 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.  

Tuffy Tire & Auto Service Plainfield
23846 W 135th St
Plainfield, Illinois 60544
815-436-1337

More articles from Tuffy Plainfield

Don't Start with That (Bad Starter Motor)

March 8, 2026

We've all heard that expression, "That's a non starter." When it comes to your vehicle, that's not music to a driver's ears. That sickening sound when you start the ignition and instead of hearing the engine crank, you hear it slowly turn over and your dash lights go dim. There can be many reaso... More

Losing Your Cool (AC Condenser Replacement)

March 1, 2026

Its always more comfortable in your vehicle when you can control temperature and humidity in the cabin. Air conditioning, which is standard on most newer vehicles, is a vital part of that comfort, and a key component of that system is the condenser. The condenser converts the refrigerant gas into... More

T for Transmission, T for Trouble (Automatic Transmission Trouble Signs)

February 22, 2026

One of the hardest working components of your vehicle is its transmission, shifting gears up and down when you need it to. The transmission is vital to your vehicle driving properly, and if you start to see signs of problems in it, its best to have them fixed earlier rather than later. (Since ne... More