Replacing O2 sensors [Archive] - Forum


View Full Version : Replacing O2 sensors

04-25-2007, 10:58 AM
How do you know if they're going bad or need to be swapped?

04-25-2007, 12:07 PM
You'll get an Engine Light on your dash most likely.

04-25-2007, 02:30 PM
with the scan feature, you can watch for laziness in the signal, that is a tell tale sign of a bad sensor, upstream or down, also bad fuel trim values would be another. the problem with the scan tool though is that it doesnt refresh fast enough, so using an oscilloscope is the best, but a scan tool will do. if it is reading too high or low all the time then its going out, it should switch the signal constantly from rich to lean from 300mV to 800mV back and forth.