o2 sensor problems

i have a 90 xj and i cant pass aircare out here in canada, stuck it on a diagnostic computer and found out that the o2 sensor isnt working, so i got a new one put it in and i still failed, but heres the thing, i stuck it back on the diagnostic tool, and found that its still not working although its brand new, could it be that the computer is screwed up? does anyone know if there is a way to bench test a o2 sensor to see if it does work or not?

any info would be greatly appreciated
nick

I have never heard of a way to bench test for an o2 sensor. but i would check the wiring harness connectors from the o2 all the way back to where the wires go through the fire wall.

just my .o2

Jeremy s.