Need help: '99 S80 with code p0036
 

I am attempting a fix-it-myself, but my research shows that this is a "bank 1 sensor 2". Am I correct in assuming that it is the post-catalytic converter sensor for cylinders 1-3? Someone suggested replacing "both", but I am not sure if that meant both bank 1 sensors or both post-catalytic converter sensors. Any help would be appreciated. I have been fearful of doing work on this car, but it is getting old enough that I can invest less in repairs by doing it myself and not feeling as if I am feeding a horse that won't run.

Should I avoid Bosch's downstream/upstream/or universalsensors?

Thanks for any assistance.:confused:

this is what i got from Chilton Library site but its for 2000 S80:

Bank 1, Sensor 2

-Before servicing the vehicle, refer to the precautions.
-Raise and safely support the vehicle.
-Remove the lower engine cover.
-Disconnect the heated oxygen sensor cable harness above the sub-frame.
-Disconnect the cable harness from the SIPS member.
-Remove the screw for the cable harness clamp in the three-way catalytic converter.
-Remove the rear heated oxygen sensor. Use Proper tool.

To install:

-Install the rear heated oxygen sensor. Tighten to 33 ft. lbs. (45 Nm).
-Reconnect the heated oxygen sensor cable harness above the sub-frame.
-Reconnect the cable harness from the SIPS member.
-Install the lower engine cover.
-Reconnect the cable harness clamp in the three-way catalytic converter. ----Tighten the screw.