Mine was related to water in the spare tire well. My right rear drain hose from the sunroof was detached, causing water in the headliner, which found its way out the pilar near the tail gate and into the cargo area. Took me a while to figure out where is was coming from. My tire / battery well was half full of water as a result.

My Indie was able to disassemble the module (which is located in the plastic housing just right of the battery in the battery well below the spare tire) and clean it up. After about another month of inconsistant diagonstic codes and the SLS light coming on and off, I bit the bullet and had the module replaced (about $130-$140 for the module alone) and reprogrammed for another $75. That was 6 months ago and all is good now.

All-in-all, it took about 2 or 3 months to get everything completely dried out and determine the cause, and diagnose the SLS, which ultimately was an educated guess to just replace the module, as they could not see any failure in any other part of the SLS.

All this from the failure of a $10 rubber hose (drain hose for the sunroof)

BTW, an after-market OBD code reader cannot access the codes for the SLS. They require the more sophistocated code readers at a qualified shop.

Good luck