Hi, I'm sure this issue has been dealt with in the past, however I have searched without success to find the answer.. so if someone could help I would be grateful.
09 XC70 non turbo 3.2
It had a software update last week and the Catalyst efficiency codes were thrown for both Bank 1 & 2 two days later.
I scanned the o2 sensors with an OBD scanner which only shows two sensors. Which two I don't know, as there are two banks and therefore 4 sensors, but they were seen as o2-1& o2-2. The voltage appears to fluctuate on the downstream as much as the upstream which would indicate a failed Cat' but which one??
Could the software update have caused this?
Isn't it unlikely that both Bank 1 and Bank 2 would fail at the same time?
Doesn't appear to be any vacuum leaks.
Could something else be going on???
I've used cat clean -desperate measures, didn't do anything, light still on!
Does anyone have any ideas?
I'm stumped.

 

We’re you able to get these two codes resolved. I’m having a hard time with my xc90 3.2l I keep getting P0420 P0430. I had lots of codes when I purchased. But I was having 4 5 6 misfires. I put new plugs and swapped the coils around not new. Also replaced the thermostat, which I must note the Duralast part from autozone was not a perfect fit. I have no more misfires. But these two codes stay.

 

These are the Catalytic converter efficiency codes - what they are saying is the rear O2 sensors (post cat) are still detecting oxygen. This can be caused by contaminated cats that are not heating fully, issues with the O2 sensors or something as simple as an exhaust leak or by somebody who installed after market parts that are not up to OEM specs. If you don't live in a state with strict emissions testing, you can consider using a CEL-BOSS spacer to move the rear sensors away from the main airflow (a common trick for tuned engines). I'd start by checking around for exhaust leaks, particularly by the flex pipe. There are also Youtube vids where people advocate cleaning the cats although I'm not sure if I've seen any testimonials about that actually working

 

I’m going to take it for testing of the intake and exhaust for leaks. I was having the misfire codes before repairs. I didn’t see these codes until I removed the intake I noticed some cracks around the vacuum house on the purge valve I made sure that was sealed. The long hard plastic hose seems good. The intake gaskets all looked good. I don’t hear an obvious exhaust leak. My gut tells me the misfires ruined both cats... but my scan data is weird From the research. My bank 1 sensors have hardy no activity and bank 2 is up and down like crazy. I got the truck at a good deal... but I think I see why. Local Volvo repair shop said 750 each upstream cat used! 1980 new. I always go to them for genuine parts but heck, I’m think after market cats. Then the o2 sensors are 500 for 4. Wow. I hope someone here can help I have pics of my scanner data. Thanks.

 

yep, that's why I suggested looking into a cel-boss spacer. If your car is running good and can pass emissions, it may be worth considering.