Hi all and thanks for taking the time to read this.

So this is my first Volvo and first use of the forum ,and as a ''car enthusiast'' with more cars than I should have,
I realize that the answers I am seeking are probably already somewhere on the site, however I have been
unable to locate them... So thanks for your patience.
I have owned many traditional 4x4's over the years , but this is my first AWD , and I have only dealt with old
school stuff and I am stumped with this traction issue.
I live in the US but am building a home off grid 15 miles up a rough dirt road in the French alps (grew up here);
I come every summer for a couple of months and hammer away. For the passed 18 years I used a first generation
Nissan Pathfinder that has ,along with an WW2 military trailer, done a reliable job of hauling materials up the mountain.
But in the interest of having a vehicle that could perform the same job and allow the family an I to do some comfortable
road trips as well we purchased a 2007 xc90 with a 2.5 gasoline motor and less than 100 000 miles. The car runs great
and has been a real pleasure to drive. Before settling on the xc90 I watched some YouTube clips of guy's with wheels
18'' of the ground still getting great traction and that was a big part of deciding it was Ok to move on to a
''non transfer case'' vehicle.
On the first steep hair pin I was stuck wheels spinning...got a run for it ,got up the hill and spent the evening studying
how the xc90 system works, tried again the following day and was relieved to see the back wheels spinning as well
as the front; so the rear axle is engaging but apparently whatever triggers the brakes to lock the spinning wheel(s) does not.
I ordered a Volvo diagnostic tool; to my dismay about a dozen codes popped up, however most were related to wipers,
climate control, sound system and other ''non essential'' things. The only code that I could find that may be related
to the issue is ABS 0136 (brake pressure sensor 1 and 2 outside it's permitted range). Can anyone out there tell me how
to interpret the message, and if that is possibly a cause for my wheel slippage.
Brakes work well; brake pads look good, discs do show wear.
In case you are wondering there is not a Volvo dealership anywhere near here... And I have always been able to
resolve or at least diagnose my own car problems, so I am hoping this xc90 doesn't prove to be beyond my ability's...
Thanks again for any help/advice you can provide.