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.
Car Problem Reports
GMC Yukon 4WD Transfer Case Position Sensor/Selector Switch May Fail
GMC Yukon Problem
Drive Train Affected: 4WD
Average Mileage: 106,000 mi (70,000 mi - 134,000 mi)