Problem Description and Possible Solution
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 be of assistance in determining the exact fault causing the message to be displayed.
Average mileage: 143,870 (64,500–211,100)
Drive Train affected: 4WD
20 people reported this problem
selector switch not working no lights,got a new one same thing no lights,service 4wd still on dash ,4 wd not working at all
Service 4WD message come on and the transmittion will not switch from 2WD to 4WD or 4WDL. Turning the truck off for a short period of time and restarting the truck will reset the system. The 4WD switch will work properly for a short period of time. The meesage will reappear and the system will lock up again.
I have replaced the encoder motor twice and the shift control buttons on the dash and the SERIVCE 4WD light continues to come on when the truck is cold. In the summertime the message doesn't appear. In the winter, after the truck is warmed up, the 4WD works fine.