08 bmw 328i p0430 catalyst system below threshold bank 2

Question

I just filled tank with injector cleaner and good gas but the code cane on after I had disconnected battery and changed window regulator. I was hoping that I might get I to clear up with the cleaner. But what side is bank 2? And do you know what the ohm readings should be on sensors? The catalytic converters aren’t too bad but the 02 Senaida cost about same locally, around 100. But I don’t want to be a part changer I want the issue fixed right there’s 121000 miles on car and it doesn’t have a mnybsoubds like a knock or valve noise. Exchaust doesn’t have a smell. I’d appreciate help