Secondary O2 question

Rusty Accord · Sep 13, 2017

I've got a 99 sedan with an F23 engine that has a ULEV window sticker on it. I'm looking at replacing the cat with a Magnaflow Cat, and am wanting to know which O2 sensor to use, as there are 2 called out for the rear sensor on Honda's parts site. Does it really matter which one I use? I was planning on getting a new Denso sensor using an interchange number for the Honda sensor.
Thanks for any help you can offer.
Side note; I'm also replacing the rest of the exhaust (cat and cat back system) and would like to be done under there before winter sets in. Well that and I want to turn off the check engine light for the PO420 code.

RedRyder · Sep 13, 2017

What are the part numbers? Maybe one of them is just a revision.

Accordx · Sep 13, 2017

Ah, the good old P0420 code. Popped up and I reset it, popped up again then disappeared a few days later and I haven't seen it since. I would assume the two you found are interchangeable but don't quote me on that haha.