I bought a sensor myself which looked exactly like the original except a blue sleeve for the wiring. Its a bosche oem. I believe its from kemparts.
It didnt work in my car. no-input error. I decided to put back my old 02 back in the car because i would get a couple of days out of it before I would have to reset it. My question is.. how do you know that your other one is for a 2.4L ? Because thats what i'm suspecting the one I got was for also? Do you have any particular numbers on it? I am hesitant from getting another I till I know forsure (like yourself) that I'm getting the right one (besides spending $300can at the dealer just for the part.
All I did get out of the dealer was that the airpump doesnt matter for the front 02. Only effects the rear 02.
And I dont know why the damn things cost so much for a volvo especially since one for a GM is like $20 What gives!