Well, I'm having the same issue with my '11 JGC. For the past week the "Serv 4WD" light has been intermittently flashing on for most drive cycles, and sometimes it will come on later in a drive cycle or not come on at all. It coincides with the ESC light illuminating despite me not having the Selec-Terrain in Sport mode, or without me turning the ESC off manually with the dash button.
Noticed the other day, during a good rain, that when I turned around in a parking lot it oversteered, which is odd for the vehicle. When the AWD mode is selected as "Auto" the thing could be pedalled to the floor during a turn and drive as straight and true as my wife's AWD Audi. This may be a sign that the AWD is disabled, which would explain the "ESC off light".
I've tested her offroad at least 3 times and engaged all the Selec-Terrain modes as well as low gear, descent control, and drove her through some relatively deep mud with no problems. My assessment is all 4WD capabilities are still functioning well in both High and Low settings.
My WK2 is an Overland with Selec-Terrain, QDII, and QL. Haven't had one mechanical issue with the vehicle since I bought it almost 2 years ago at 40,000 miles. This issue just arose around 85,000 miles.
So, I took my Jeep to a local indy shop that rates highly among Jeep enthusiasts and just about everyone else that's used them for repairs/modifications for the last 30 years. The service manager called later in the day and mentioned they pulled a DTC from the DTCM that was isolated as being a faulty code generated from the ELSD due to faulty programming from Chrysler. Seems I've read several other people were told the same thing, only to find out that the "flash" repair process isn't the fix for everyone.
Here's the TSB I found online in reference to "flashing" the module: http://www.wk2jeeps.com/tsb/tsb_wk2_2100811.pdf
Unfortunately, the indy shop had their computer out for repair, so they cannot perform the TSB flash until next week. I'm driving the Jeep this week and take it back on Monday the 29th. I'll let you all know if the flash fixes the issues or if it comes back on the day after as many of you have experienced.
Questions: How much has everyone paid their dealership/indy shop for this reflash? Does anyone know if TSB 21-008-11 is covered under any warranties for Jeep or the dealerships?