Took my xc90 in for a diagnostics today for my
AWD. AWD is not working correctly very limited power to the rear. the mechanic said I need to replace the whole AOC and DEM. the codes he pulled are
BCM-0094: communication problems with DEM: DTC active
BCM-0095: communications problem with DEM: DTC active
CEM-1a64: Communication with AOC control module signal missing: DTC active


I have read a lot of times that the DEM pump fails on these xc90. Is it worth it to replace the whole AOC and DEM assembly or try and go with a new pump and filter. Help would be greatly appreciated. Thanks

 

Without look at at the car I can't exactly diagnose the car but when you get communication faults the module is usually bad. Are you sure you're getting power at all to the module. I have seen the fuse for the DEM blow so you might want to check to see if it is. If the fuse is blown disconnect the DEM and AOC and put in a new fuse. Then plug in the parts one by one and which ever one blows the fuse is the problem.

 

I checked the 7.5 amp fuses in the back panel behind the taillight they look good. I saw a forum online those were the ones to look at. I'm guessing the DEM is dead. Maybe not the AOC.