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2007 Volvo xc70 AWD problems

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2001 - 2007 V70
2004 - 2007 V70 R
2001 - 2007 XC-70
2001 - 2009 S60
2003 - 2007 S60 R

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Fataqui
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Joined: Wed Apr 19, 2017 1:41 am
Year and Model: 2007, xc70
Location: Maine
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2007 Volvo xc70 AWD problems

Post by Fataqui »

Recently my old 07 xc70 starting having AWD issues, it would work one day, then the next day it wouldn't. So I took it to the dealer and had a diagnostic done. I was told the "feed pump" had gone out and I was quoted 1200.00 to fix it plus they said my propeller shat was also bad, the center universal joint was pretty much shot. So i had both items replaced for almost 3600.00, crazy. They then called me to report that my DEM was dead and that would be another 2600.00. I was like NO, just finish what I had already authorized and I would come get it. So when I picked my wagon up I asked them for my old pump and they said it was thrown out and that I should have asked them to save it before the replacement was installed. Which made me really mad, so they were like you have to leave now, anyway, seeing like they were not wanting to help me anymore I just left. But before I left I pulled the #23 fuse from the REM so I wouldn't burn the new pre-charge pump out. So when I got home I ran VIDA and saw 100's of errors, related to stuff that had no problems before this. They were airbag errors, immobilizer errors, etc. So I cleared everything and all those crazy errors went away. But I wondered why they even were there to begin with. So now I am left with the following errors...

BCM-0111
BCM-A031
BCM-A032
DEM-0007

So I put the #23 fuse back in before resetting everything, and then took it for a 20 mile drive after when I go to DEM > VEHICLE COMMUNICATION > the DEM reports its getting power and I get these readings...

DEM-DEM Voltage 11.7 V
DEM-CEM Voltage 11.88 V
DEM-Oil temperature 33 C
DEM-pump current 14 mA
DEM-Oil pressure 0 MPa

So my question is... How can my DEM be dead, if its reporting these values, really the only value its not reporting is the "Oil Pressure"? So could someone please help me figure out what is really wrong with my AWD!

TIA!
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oragex
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Re: 2007 Volvo xc70 AWD problems

Post by oragex »

Sorry about the bad experience at Volvo, don't hesitate to leave a feedback on local.google.com
For the AWD, if the DEM has internal corrosion, usually Xemodex can fix these. The car would normally still drive with only FWD, but if the DEM goes bad the engine may not even start. So for now maybe leave it there, perhaps the problem with intermittent AWD was only the pump. But know that the spline collar also goes bad on AWD and that's another few thousands
Fataqui
Posts: 16
Joined: Wed Apr 19, 2017 1:41 am
Year and Model: 2007, xc70
Location: Maine
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Re: 2007 Volvo xc70 AWD problems

Post by Fataqui »

Just a quick update....

I pulled the Haldex unit on Saturday to replace the "Pressure Sensor, #30759668", I also tested the solenoid using a old Borg Warner service reference chart from 07/12 and that showed me that the solenoid was okay, so i just replaced all the o-rings on the solenoid and then I simply replaced the Pressure Sensor with one I pulled from a 06 XC70 from a local junk yard, but before I did that I also replaced the o-ring on the Pressure Sensor. I also bought a new "Haldex Repair Kit, #30783288" because the gasket seal on my original one was no looking very good. Then after getting the Haldex unit back in, I refilled the unit with fresh oil, and I didn't drain any out, I just filled it until it began overflowing, after I just installed the fill/drain plug. I don't ever remove 75ml/100ml because my original Haldex Service Manual doesn't say to do that, only Volvo does, and I have done it that way for years without any troubles. So after that, I cleared the DEM, SAS, BCM, CEM after driving it for about 60 miles, after I checked everything out, the DEM final came back to life, everything was working as it should. What I mean by that, before I replaced the Pressure Sensor, I couldn't get the Haldex unit to actually state that it was powered ON and running, and I also couldn't get a pressure reading, only a temperature reading, and the solenoid was not getting powered up. But afterwards, the DEM reported that it is running and ON, plus the Pressure Sensor was now giving a pressure reading within the acceptable range, and the solenoid also came back on line. So replacing the Pressure Sensor total fixed my DEM-0007 error. But still after all that I was still left with....

BCM-0111
BCM-A031
BCM-A032

So I ran a network trace on the entire DSTC system using Vida, and everything came back okay, yaw sensor, steering wheel control module, DEM, but I noticed that the steering wheel angle sensor, the (clockspring/contact reel), was acting very strange, if I turned the steering wheel it would show the degree of movement as I was turning the steering wheel, but if I stopped turning the steering wheel, and just held it there, it would report that the steering wheel was now at "0" degrees again, so basically no matter how much I turned the steering wheel when I stopped turning the steering wheel, the (clockspring/contact reel) would report to the BCM that it was at "0" degrees which completely didn't jive with the yaw sensor, so the CEM finally gets tired of that craziness and blocks the BCM from communicating with the DEM unit. So I went back to the junk yard and pulled 2 (clocksprings/contact reels), one was a older unit #31264469 in a 05 XC90, and the other was a #31313083 that I pulled from a 06 XC70, and I paid $40.00 for both of them. So I installed the #31313083 unit seeing it was newer, and then I re-calibrated all the DSTC modules, then I cleared the BCM. After that I simply started my XC70 and BAM no more "Anti Skid Service Required", and the all wheel drive is working great again, happy me!!!

So like others have stated many times before...

DEM-0006 = bad AOC pump, (its dying or its dead)
DEM-0007 = bad AOC pressure sensor, (faulty reading, no pressure reading reported, only the temperature is reported)

and...

BCM-0111 -------
BCM-A031 ---------- = bad clockspring/contact reel
BCM-A032 -------
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