I just took my relatively new 2012 Overland Hemi (with ORA II / QD) down a long trail here in Colorado. I drove for several miles on loose dirt in 4H with Select-Terrain on "Sand/Mud", and then "Service 4WD" light came on. The 4WD system continued to operate normally, however, except for the light.
I turned the car off and back on, and the light was gone, so I kept going. A few miles later, same thing. Now I am starting to get worried, as the trail is essentially a 12-mile long descent, with no way out except back up the hill, and it was highly unlikely I'd make it out without 4WD. But everything was still operating fine, except for the light, and I was not in any mood to turn back around.
For some reason, it occurred to me that I had never driven this long a distance before in Sand/Mud mode, so I "rebooted" the car (again, clearing the light), and left it in Auto for the remainder of the descent (another 8 miles, maybe). No problems whatsoever.
On the way back up, I kept it in 4L and Sand/Mud mode the whole time, and again had no problems.
I suspect the vehicle does not like being left in 4H in Sand/Mud mode for a long period. Maybe too much heat generation in the transfer case with the variable torque split changing all the time. Running it in 4L locks the transfer case, which explains why it would tolerate that better.
I will ask the dealer tomorrow when I bring the car in (one of their wheel weights fell off on the trail,
) to check the codes and see if he can tell me what happened - but that's my theory.