0410 and 0134, replace O2 sensor or wait?
I bought my '98 355 this week and decided that after 4 days of ownership, it was time to start modifying ;-). I knew from the last major that was done this year before I bought the car that the aftermarket cats that were on it were failing but the last owner decided to hold off on replacing as they were still ok at the moment. I'm swapping them out for track pipes and getting rid of the Tubi exhaust for a Capristo (anyone looking for a Tubi?!).
After getting the expected CEL that I was waiting on for the ailing cats after putting a couple hundred miles on the car, I pulled the codes and got P0134 that triggered the CEL and P0410 as pending. The P0410 was from the typical blown fuse. Swapped it out and now I can hear the annoying fan on cold starts so that should get rid of that code. My issue now is that, as I understand it, the heater for the O2 senors is on that same fuse. So I'm wondering if the Bank 1 Sensor 1 P0134 error I'm getting is just related to the cat failing or also from the P0410 and the fuse being blown. Long story short, should I replace the O2 sensor while I have everything apart or is it likely fine?
Car has 17,500 miles and Fabspeed headers. I don't know why the original cats were replaced nor what brand. After pulling them off the car last night there is no branding on them whatsoever, only thing I can tell is that they are made of stainless. The car was owned by a collector for its entire life before me and always serviced at a Ferrari dealership, so it's a bit of a mystery on these cats, but I'm scrapping them anyway.