I don't know which one is which. There are two O2 sensors on my car, one very close to the engine and the other one a little further back. I need to know which is which so I can decide on whether or not I will be changing this item out.
I had a check engine light come on and I went to checkers (local parts store) to get the computer scanner on it and it showed the #1 O2 sensor to be bad. it only has 70000 miles on the car so I don't think it is the #2 O2 sensor.