Diagnostics An oxygen sensor that’s going bad or has failed altogether won’t always throw a check engine light or trip a diagnostic trouble code. Sometimes if there’s an internal problem ...

One of the most common reasons your check engine light comes on is a faulty oxygen sensor. Here's how to detect problems with the sensors and how to fix them.

Finally, a bad O2 sensor can have other consequences also. Besides potentially causing damage to your vehicle, you'll also probably fail an emissions test if you have a faulty O2 sensor.

Oxygen sensors are not among the maintenance items that need to be replaced regularly, so they typically are replaced only when they fail.