So I've got this 2004 S60R (trying to sell it possibly) and one of the issues id like to fix on it (depending on what it's gonna take) is the O2 sensors, i can get the codes if needed but its basically the heater circuit for both sensors and saying both sensors have "no activity detected"...

when I got it it was just "no activity detected" for the upstream sensor, and the rear sensor was throwing a fit because no cat, put on a spacer and then that went away, replaced the upstream sensor with a Bosch one and it seemingly threw everything out of whack. fuse is good, wiring looks fine from what I can see for both sensors, I was careful with both sensors etc. downpipe is stock, just cat deleted so I don't think the front O2's position or anything is affecting it because the piece where that bung is, is factory pipe still. would really like to get it fixed for my own peace of mind, and so I can sell it easier... I've heard anything from the MAF affecting it, to a bad ECU so any help would be appreciated. again not looking to get too involved if possible so if its indeed ECU or something I'm probably not gonna bother...

I did try to search but couldn't find much or anything for my specific case...

 

Did you happen to accidentally order a O2 sensor with 4 wires instead of 5?

 

Well I posted on another forum as well, and also after driving 200+ miles since I last reset it there’s no longer any codes for the front sensor (I only noticed them after I first cleared them after replacing it) and even now after about 500 miles still not front o2 codes. I bought the sensor on RockAuto and selected the upstream Bosch sensor, so unless they had sent me the wrong one which I doubt since they’re a different connector… then don’t think that could’ve happened. I went ahead and bought a new rear sensor since it looked pretty old and crusty, as did the old front sensor, when I was doing the spacer for the rear sensor so I’ll report back after that I guess