Hello,
Wondering if anyone could give me some insight. I recently had code p0432 come up(main catalyst below operating threshold (bank 2)). And an emissions test showed I was almost double on my NOX emissions as what is allowed. These 2 are obviously related what I'm wondering is if the high NOX could be the cat converter being no good or is it more likely the o2 sensors. Or neither and just lean fuel causing both? I looked and could find no obvious vaccuum leaks or exhaust leaks.
I should mention that the car is running fine an there are no noticeable problems, ie running rough or stumbling,hesitating.


Any help or thoughts would be appreciated.

 

I would say possibly bad O2.

 

Thanks tech.
I m going to grab a scanner that shows live data so hopefully that will isolate the o2 sensor(s) if that's the problem.

 

too much nox is the after affects of no catalyst operation and high temperatures in the cylinders, which could be caused by a rich biased oxygen sensor. it could also cause predetenation if it gets too hot. sometimes the egr system is inop but i dont think volvos have that.. or i know mine doesnt...

 

Thanks for the input. I got a new code P0422 same code but now in the other bank. I still haven't got the oxygen sensor monitor to run so am waiting to see if I get anything referring to that. Can't believe its this hard to get it to run its cycle. I've made 5 one hour trips I figured it would cycle by now. Guess I'm not being specific enough on the drive.[:@]