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Discussion Starter · #1 ·
So, after extensive searching on the forums, I'm still a bit stuck.

Here's my XC90: https://www.swedespeed.com/projects/project_xc90/index_Project_XC90.html



I had to keep the XC90 parked outside for a few weeks, and it was facing downhill in my driveway. One day I hopped in and got the Anti-Skid Service Required message. My scan tool (not VIDA/DiCE - yet...) is giving me a Permanent Fault code BCM-0094 Communication Between Control Units; Communication problems with AOC.

In addition, I've seen an Intermittent Fault BCM-0148 communication between control units; wrong configuration ID.
There's was also an Intermittent Fault BCM-0115 communication between control units; Communicational problems with SAS, signal missing.

Am I looking at multiple issues here, or is there a chance that this is multiple things all occurring at the same time? I was able to clear the intermittent faults and they haven't come back, however the BCM-0094 is indeed a fault that will not clear.

I've tried looking for a flow chart specific to the fault that I have, but I'm not having any luck, other than the one on XeMODeX, which doesn't really address the BCM-0094.

Any tips or help are welcome!
 

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Was the battery drained ? Always disconnect the car battery when parking the car for several weeks - have the key in POS II when disconnecting and connecting back (with headlights ON)

Do the Climate controls work properly ?

AOC that would bring me to the DEM (AWD)

I would look in this order (from cheapest to the worse): axle (drive shaft) center bolts, reluctor rings (tiny cracks), clockspring (SAS), brake pressure sensors, DEM
 

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Check the AOC fuse. I don't have the number handy, but its in the back and its a 7.5 amp fuse. I think it's labelled AWD in the owner's manual.

The SAS code will likely need a new clockspring if it returns.

Those codes won't be caused by axle center bolts, reluctor rings or brake pressure sensors.
 

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Was the battery drained ? Always disconnect the car battery when parking the car for several weeks - have the key in POS II when disconnecting and connecting back (with headlights ON)

Do the Climate controls work properly ?

AOC that would bring me to the DEM (AWD)

I would look in this order (from cheapest to the worse): axle (drive shaft) center bolts, reluctor rings (tiny cracks), clockspring (SAS), brake pressure sensors, DEM

Is the headlights ON a thing? Just hadn't heard that before. What happens if not?
 

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Was the battery drained ? Always disconnect the car battery when parking the car for several weeks - have the key in POS II when disconnecting and connecting back (with headlights ON)

Do the Climate controls work properly ?

AOC that would bring me to the DEM (AWD)

I would look in this order (from cheapest to the worse): axle (drive shaft) center bolts, reluctor rings (tiny cracks), clockspring (SAS), brake pressure sensors, DEM

Is the headlights ON a thing? Just hadn't heard that before. What happens if not?
No. That is irrelevant. As is the position II part. Nothing happens.
 

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The reasoning for that pertains to the airbags. If you worked on or near the SRS system, Volvo wants you to reconnect it with the key in position II so that if you somehow created a short, the airbag doesn't blow up in your face when you turn the key on. Headlights have nothing to do with it.
 

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The reasoning for that pertains to the airbags. If you worked on or near the SRS system, Volvo wants you to reconnect it with the key in position II so that if you somehow created a short, the airbag doesn't blow up in your face when you turn the key on. Headlights have nothing to do with it.

Agreed about the SRS, but I am under the impression it was said that having the headlights on would prevent a power surge that sometimes causes the thermistor in the CCM to fail
 

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Never heard of that and cannot find any documentation of it. VIDA specifically states the reasoning behind the position II part.
 

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Discussion Starter · #10 ·
The battery never died on it. I just checked out the fuses in the rear and none of them are blown. I talked to the dealership and they want $200 just to diagnose it (apparently I'm in the wrong business). Buying a DiCE would be cheaper...

Also found out that in Virginia, if the anti-skid service message is on then it will fail the annual $20 Virginia Safety inspection. That's not required until the end of September for me though so I have some time.

So.... I don't want to just grab the cheapest DiCE I can find on eBay or Amazon. Can anyone recommend a trusted seller? I've already found a VIDA image and plan on setting it up in a VM while I wait on the DiCE to arrive.

I'm also going to try to get those two relays on the CEM and see if that does anything.
 

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Discussion Starter · #11 ·
Okay. I'm getting battery voltage on two of the wires on the 4 wire connector that goes to the AOC. I popped off the DEM just to make sure that there wasn't any obvious water or oil infiltration. The connectors on the pump and the 4 wire connector are all clean. The fluid is still fairly clean after the filter and fluid change 10k ago.

Now that I've put everything back together, I started her up and no message. Since all 4 wheels are up, I popped her in gear and BOOM! I have AWD again.

Maybe I just needed to let the pressure out of the kanooder valve and top of the blinker fluid to fix it. Weird.

Anywho, stay posted. As my oldest vehicle, I am considering letting her go to a new owner so I can make room for an XC90 T8 that I've been eyeballing.
 

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Discussion Starter · #12 ·
Okay. I'm getting battery voltage on two of the wires on the 4 wire connector that goes to the AOC. I popped off the DEM just to make sure that there wasn't any obvious water or oil infiltration. The connectors on the pump and the 4 wire connector are all clean. The fluid is still fairly clean after the filter and fluid change 10k ago.

Now that I've put everything back together, I started her up and no message. Since all 4 wheels are up, I popped her in gear and BOOM! I have AWD again.

Maybe I just needed to let the pressure out of the kanooder valve and top of the blinker fluid to fix it. Weird.

Anywho, stay posted. As my oldest vehicle, I am considering letting her go to a new owner so I can make room for an XC90 T8 that I've been eyeballing.


I spoke too soon. The message is back. Still coming up as a BCM-0094 communication with AOC error. Looking like the DEM is being a jerk.

Any recommendations on repair places with reasonable rates?
 

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Could be the yaw rate sensor under the passenger seat and under the amplifier. Has this car had any water intrusion due to the dreaded A pillar sunroof drains or via the air inlet plenum for the A/C that is just in front and below the windshield on the passenger side?
 

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You were playing with the pump and it worked for a bit. When I changed the pump our problems went away and the AWD worked.
 

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Discussion Starter · #17 ·
Nah. The A-Pillar sunroof drains are cleaned once a year. In fact, I just did that a couple of months ago when I put in new A-Pillar trims... My old sun visors would catch between the windshield and trim cover, and started peeling them... I can pull the amp though to be sure tomorrow, although I'd think that would be a different DTC.

Also, this ought to be a sticky or something... https://www.dtcdecode.com/Volvo
 

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Discussion Starter · #18 ·
It's not the yaw sensor with that code. Likely a bad DEM.
I'm thinking the same thing. The filter and fluid was changed last year. None of the fuses in the rear were blown. In addition, I have the same voltage on pins 1 and 2 as I do on the battery when the key is in position 2.

Now, should I rebuild with someone like XeMODeX, for $650 or pay roughly the same for a new one from the dealer, or maybe take my chances with a junk yard part and a $400 clone from them??? Decisions...
 
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