Possible Cat problem
Hey Scotty love your channel. I have a 2017 Volvo xc90 T6 108000 miles , engine code p0420 keeps sending the check engine light on then a few days later off again and then on again. The code was there even after the light went off. I just had the flex pipe repaired by Volvo and this problem began a few days later. I brought it back for an oil change and asked them to check it and they said that since the code is off its not a problem. They also said they took it on a road test and all was good so they cleared the code. I did not believe them and sure enough the next day the light is back on. Do you think its the cat or could it be something that wont cost me an arm and two legs to repair.
Take it back and demand they fix their flex pipe work (or any other work) that preceded the codes.
As mentioned above, I would do the same and take it back to them to correct the issue it sounds like they created.
They may have done a poor job servicing the flex pipe, and it's leaking.