I have read several responses to the service 4wd message and I agree, it is frustrating that most service managers have never heard of the problem much less a solution. I finally found one who pointed me to the indicator switch on the transfer case, and I purchased the switch for $32 and replaced it. I still get the error message, but mine is intermitent rather that a constant like some people have indicted.
Any ideas on what else I may check, ie, is their another component that works with this switch that could be malfunctioning or is it possibly shorts in wirinf since the message is intermittent? Any suggestions would be appreciated.