I have a 2000 s80 t6 with 140k miles. When the car is turned on it will drive for ten feet then the transmission will disengage. If the car is turned off and restarted it will go for another ten feet and then disengage as if it was put into neutral. It does not work in reverse and the sequential shift does not work either. There are 7 codes but most have to do with emissions that i don't care about. There are two codes that the reader did not specify p1171 and p1181. The engine is running fine. I replaced the transmission pan gasket and fluid this summer and the fluid still looks fine.

 

1171 & 1181 are fuel trim codes.
Here's some info on our crappy transmissions:

Volvo S80-XC90

 

An update: I manually shifted the sequential shift into third and the car drove forward. I was then able to back it up and then drive froward several times in drive. I then backed up a hundred yards and tried to drive forward in drive but the car moved very slowly. I stopped shifted manually into third and the car then drove forward again. The fluid levels are fine and the fluid looks and smells brand new. The wiring under the air cleaner into the trans looks fine although the conduit crumbles at a touch.

 

final update (I hope). For anyone who experiences this problem in the future, it appears that the transmission filter was completely blocked. I changed it and the transmission is working beautifully to this point. A word of advice if you drop the transmission pan I would suggest replacing the bolts because when I tried to reinstall the pan three of the bolts snapped off.