Important: 
   •  Perform the 
Diagnostic System Check - Vehicle
 before using the symptom tables in order to verify the following statements are true:       -  There are no diagnostic trouble codes (DTCs) set.       -  The control modules 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 . | 
| • | 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 cause intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: