took truck to dealer and they could not get a code for the Service 4WD. before this happened i was getting pinging sound from up front when i turned my truck off, i don't get this noise anymore and now my 4wd doesn't work. anything in the front associated with 4wd?
service 4 wd message on 2003 Chevrolet Silverado 2500
by cauntfix in Beaverton, OR on February 20, 2011
The 4WD transfer case encoder motor position sensor or the selector switch may fail causing the service 4WD message to be displayed. Fault code(s) stored in the transfer case control module will ...