Of course before you go replacing an O2 sensor you'll want to be sure that's the problem. Even the parts are expensive, not to mention the labor if you're paying a shop to do the work for you. A Check Engine Light can mean a lot of things, and even though the oxygen sensor is often the culprit, there are hundreds of other possibilities.
How do you know if your car or truck needs a new O2 sensor?
The answer to this question is simple. Your Check Engine Light is on because the computer is "throwing a code." In tech speak this means that the computer has detected a malfunctioning system, and has produced an error message which caused the Check Engine Light to come on. With a code reader, you can read this error, called an OBD Code, and determine if the O2 sensor is the culprit. If you don't have a code reader, there's a free and easy way to retrieve that error message. Learn how.