I am posting up my findings for future reference. As these XC90's start coming down in price i am sure we will be getting more and more fellow volvo owners making the move to the xc90. Many will have AWD problems and haldex problems.
If you got a DEM-0006 code that means your Haldex pump (#3) is bad. I got one used from
www.vwvortex.com turns out that the haldex units on audi tt's A4's S4's R32's (circa 2008) basically the AWD vw/audi family with these 2nd generation haldex units. They carry the same pump, the same pressure sensor but i am not 100% sure on the haldex unit itself. The unit i have is from a 2008 VW r32, did not try and use it since i ran out of time today at work. Volvo wanted $290USD for the pump and $115USD for the pressure sensor. I got DEM, pump, sensors and shipping for $100USD I know all the sensors from the VW works 100% in my 2003 XC90 T6 AWD Haldex unit. I did not try the DEM like i said above, no time.
If you get a DEM-0007 code it is a pressure sensor bad. thats the smallest sensor in the picture below #6. attached is the TNN for a DEM-0007 code.
Below is a picture of the haldex pump and all the internal haldex sensors, fluid guide, haldex break down.
So if you need to fix the AWD sensors and pumps, i did all the research and sensors will interchange with VW's. If you look closely at the haldex connectors it will have VW logos on them! From the parts breakdown it doesnt show the weird long sensor with the brown connector end. i dont know what that one is called but it also has the same part number stamped on it like the pressure sensor.
BTW- #10 is a filter and Volvo never has these in stock and when i wanted to order it there was a 4 week national backorder. vovlo parts manager says they never change it, i just some how feel better when it is changed out while i am in there, its $18USD
