SERVICE 4WD SYSTEM

I have 2005 grand cherokee LTD, with hemi and I seem to get a read out below the speedo that comes and goes which is SERVICE 4WD SYSTEM, I have tried the disconnect battery, did not work. Then the turn the key

4 times to find a error code, did not work. Then the local dealer flashed the computer and that did not work. They are know saying that a module somewhere in a compartment near the back seats has to be replaces. I am currently in Mexico and just wanted some input as to whether anyone has resolved this problem, as the error keeps on coming and going thanks