This Preliminary Information communication provides information to the technician about vehicles that may have a Service 4WD message on the Driver Information Center when operated below 10 degrees Fahrenheit (-12 Celsius). Technician may find C0398 or C0326 stored in the Transfer Case Control Module. For vehicles with Regular Production Option Code NQH and NQ6 and only setting Diagnostic Trouble Codes C0398 or C0398 and C0326 the replacement of the actuator motor will correct the concern. Dealer will need to contact General Motors Product Quality Center for further assistance.
