2006 xc90 v8 awd multiple can bus communication faults

[Hkanitz]

I have owned this vehicle for a couple of years. I bought it for cheap with problems I was sure I could fix. The original problems were traction control, no awd. Now this thing starts up and runs for a few, then loses guages, trans not shifting. After a few times of doing this and starting and stopping it will drive without incident all day. So far, I recently purchased a chinese dice unit and 2014d. I also bought the EWD wiring diagrams. Vida came up with these codes, cem 1a61, 1a62 1a64, 1a5e, 1a5f, df17, and uem ooo4. From what I see, the major one causing my problem is the df17 code. Apparently the can high speed and low speed are shorted together somewhere. I have never seen such a screwed up wiring diagram in my entire life! I am a licensed aircraft mechanic and am certified on most aircraft flying. I would greatly appreciate any and all help finding this short. I am leaning towards the DEM being shorted internally. Could this shut down the can communication?

[RickHaleParker]

Yes a short in one of the Modules can pull down the CAN Bus. If you suspect an internal short in a module, disconnect it, clear codes and see what comes back.

You could narrow down where a short is by disconnecting the CEM then probe the different local circuits.