OK- one of my Civics just threw a code for the downstream (secondary) o2 heater. Wondering if a primary sensor will work as a replacement? I know Ill probably have to splice wires, and I am ok with that, just need to know if itll work the same. Reason I ask is because I have a few good used primary sensors, and free is good. Thanks

 

I know they're supposed to be different but I could swear that I remember them both having the same number of wires and same wire colors. I had half a dozen of these things back when I had a garage and that's what I recall. If that helps.

 

As long as their both 4 wire you'll be fine.

 

awesome. thanks guys!