O2 Sensor Comparison
 

Is there any difference between the Bosch universal rear O2 sensor and the Bosch OE rear sensor besided the fact that you have to add the electrical connector to the universal one? BAP GEON has the universal sensor for the 2000-2002 2.4 for $56 and the OE for $142. Any performance issues or drawbacks using the universal sensors? Both are made by Bosch. I don't mind doing a little soldering to save $80+.
http://www.bap-geon.com/Catalog/CatalogResults.aspx

Go with the direct fit only. Volvo's hate the spliced universal ones.

10-4. Are these OE Bosch sensors okay or do I need to get ripped off by my local stealer? http://c2c.activant.com/ctoc/index.j...NCUlE6BlIIXnYf

The direct fit Bosch are ok.(in the link above)

I popped a P0163 code on my 2001 C70 and replaced the Bank1 S2. I erased the codes and was running through a drive cycle and it CEL came back on. I pulled the code and its the same one. P0163. I replaced the O2 sensor with a Bosh easy link. Do you think that's the problem? I saw where you said the easy links weren't good. My OBDII reader shows 0.435 on the live data stream.

did you check for possible vacuum leaks? next would be to double check the wire splices to make sure they are mapped correctly and a good contact at the original connection.

I've used the a Bosch sensor in my 850 with no problems as well as an Audi so I'd be inclined to think its a vacuum leak or possibly a reset issue. From what I can tell reading online that the "smartlink" is just a marketing term for the generic connector which you have to splice in vs buying OEM where you pay extra for a vehicle specific cable.

Yeah, I checked for vacuum leaks and exhaust leaks that could throw it off. The wires were the same color, Black, Grey and two Whites. I diagnosed it further and I think the problem it before the O2 Sensor. The DATSC Volvo site I used to diagnose the P0163 code said to check the voltage at the plug where the O2 sensor plugs in and it should be .500 or above, if it's not, use a jumper wire to ground in the plug to the chassis and it should go above .500. Mine was at .480 and when I grounded the proper pin in the plug there was no difference in the voltage. They said that indicated a problem with the ECM. I'm trying to find someone local to check the ECM so I don't have to mail it off.
I agree about the "smartlink", LOL....it makes sound..Uhhh...Smart.