Klaus, thank you for your time and your response. I just got off the phone with the service manager of the place I took the car to yesterday trying to get some kind of refund for an unaccomplished task. I asked them to resolve/turn OFF the CEL. I can barely write this to you now as I am sooo frustrated and mad with this car.

The tech replaced my rear oxygen sensor and told me that the signal was bad and it was not producing the proper voltage. Keep in mind I replaced this rear sensor twice already last year, with the last replacement being a NGK brand.
Now I have heard that many Volvo people say you must buy the O.E. Bosch sensors and forget the spliced wiring. I now have new front and rear Bosch plug 'n play sensors. They somehow were able to run the car while the CEL was OFF and give me a legal emissions sticker for another year. Great right? I drive the car home and I didn't make it 10 miles before the light is back on again. I then went back this shop this morning and the owner plugged in his fancy, schmancy analyzer to tell me that the new rear sensor is mimicking the front sensor. No difference between front and rear sensor readings. He then determines that I now need a new catalytic converter. I guess these shops today just think I will keep throwing money at this CEL until they get it right. I give up as to where to take it next. It's as if I can't trust anyone anymore.

I asked of there was a code for the converter and the tech laughed at me. It does not work that way he said. As far as what you said about trying to find out what is making the cat die, (maybe it's not the cat) who can even diagnose that at this point?

Sorry for the looong winded response.