OK here we go...Tech or anyone I need some expert advice.

1999 s80 non turbo 181K meticulously maintained. Check engine light came on about 6 months ago and yes about two weeks later the emissions testing notification arrived with a deadline of end of May. Codes are P0432 and P0422. Since then I have checked for vacuum leak (spray carb cleaner all over), replaced MAF reset codes (increased gas mileage from 19.8 to 21) check engine back on, replaced exhaust manifold gaskets (all six), reset codes check engine light back on, O2 sensors all four direct volvo parts ( needed to change anyway with the mileage) reset codes check engine light back on.

IR heat test on cat after long drive:
Front right passenger side 330 degrees before cat 515 degrees after.
Front left driver side 340 degrees before cat 500 degrees after.

IR heat test on cat after sitting idling 30 min:
Front right passenger side 290 degrees before cat 380 degrees after.
Front left driver side 290 degrees before cat 380 degrees after.

Seems cat is fine though I'm not sure. Also, this is original exhaust system, spark plugs and coil packs all replaced two years ago.

Brought it to my independent Volvo mechanic and he is stumped. His experience is Volvos for 25+ years I take it to him when the repair is to intense and have never had any issues with his work. Just trying to provide all the information I can....

Tech if your out there or any one else that can offer a suggestion, I'm at a loss and can not renew licence as check engine light comes on after 30 miles or so. From what I understand that is an automatic failure. Really do not know what to do at this point. Any help is really appreciated.

 

I am having a similar issue on my 'new to me' 2000 v70. Currently researching to find the fix. Did you find the problem with yours?

 

http://www.permoveo.ltd.uk/tabid/122...o/Default.aspx



http://www.permoveo.ltd.uk/tabid/122...o/Default.aspx



Both point to an optical sensor circuit issue. But I don't know anything about that part...

 

Well AdlerV70, I have to say I have had some success. I did pass emmissions too yeah! Here's my fix. I figured from research that one of the fronts O2 sensors was bad (I did run with the check engine light on for some time) and she was running rough. After I replaced all four O2 sensors the car now runs like a champ. But the Check engne light was still coming on. So I figured the CAT had been degraded a bit due to the bad front O2 dumping more unburned fuel in CAT. I guess the CATS on these cars are tuned pretty tight and those rear O2 sensors are the key if your car is running fine but you still get that check engine light with the P0432 and the P0422. So I put these on

O2 Simulator, angled, cel fix

These are post CAT angle extenders. They are a tight fit on the exhaust and you have to angle them towards the middle (not facing straight back) to get them to fit but it wasn't too bad a job. Anyway seems that moving those rear O2 sensors back a bit help reduce the sensitivity and allows a bit more range of play before tripping the CEL.

Let me know what your symptoms are and if you decide to do this. It seems to have worked for me and if it works for you its a cheap fix but you must make sure those front O2's are working good as those are the key to the fuel/air mix and the car running great, etc. The rear O2's are key to the "CAT efficiency below threshold" cel. I expect my cel to return eventually.....so I'm curious if this fixes you problem too. Good Luck!

 

look at the voltage you are getting from the rear O2 sensors at normal operating temp. If they are stuck at a low .120V then you might have damaged/twisted the wires as you were putting them in. At a perfect 14:7 A/F ratio they should be around .450V. I had the same codes pop on me but after replacing all 4 O2 sensors it went away. Don't forget to disconnect battery when replacing sensors. you need to look at the LT and ST trim as well. in a perfect world you want the LT and ST sum to equal 0.

 

hook the car up to a Volvo scanner and in 5 minutes I would bet you could could find the problem.

Those cat codes should be easy to confirm or not. All you would have to do is watch the O2 sensors do there thing.