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 NPO, NQH and NQ6 and only setting Diagnostic Trouble Codes C0398 or C0398 and C0326 reprogram the transfer case control module with the latest calibration from TIS2WEB and perform the setup procedure.
