as others have noted, this uses a wideband o2. either a 4 wire (Denso) or 5 wire (Bosch).

is this a non turbo? if so, i am in the same boat. i replaced b1s1 about a month ago on my 01 s60 n/t hoping to rid of an intermittent cat code. it had 240K on it so i ... Login to read more.