Hi I have a 1998 Saturn sl2. It just failed emissions (I don't live in CA) because of a busted catalytic converter and both o2 sensors. I would like to keep this repair as cheap as possible as i am just trying to get it to pass emessions. I am having diffculty finding out which finding out which o2 sensors to buy. I know there are two but are they the same? I can't find anywhere that says front and back. Any help would be greatly appreciated!!!!!

 

Buy from the dealer if you want working parts.

 

use denso brand sensors -- pull the ones you have and get the denso part numbers off them. Do not buy bosch. Do not buy universal fit

get from dealer or special order from parts house.
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I do not remember them being the same but the part numbers will tell you
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If you a getting a cat code, replace the sensors first -- start with front O2, clear codes and see if they return.
Logic: If one of the O2 sensors is dead, the car cannot figure out whether the cat is working properly.

Front gets coated with crap and needs replacement more often than rear.