Important: Perform the Transfer Case Diagnostic System Check before using the Symptom
 Tables in order to verify that all of the following are true:
   •  There are no DTCs set.    •  The control module can communicate via the serial data link.    •  Review the system operation in order to familiarize yourself with  the
system functions. Refer to 
Transfer Case Description and Operation  
| • | Inspect for aftermarket devices which could affect the operation of the automatic transfer case system. Refer to Checking Aftermarket Accessories in Wiring Systems. | 
| • | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom. | 
| • | Inspect the automatic transfer case for the proper fluid level. | 
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: