Originally posted by 93DituneEX How can I tell if my o2 sensor is bad?
The is no good way to really know for sure. You can try probing with with a voltmeter but if you have to know which pins NOT to short together -- and even then it could read fine even though it's going bad. How many miles do you have on your car? If you have over 90k the chances are it is bad or on it's way there. Once they get really bad they can flag the Check Engine Light too.