Important: Perform the Transfer Case Diagnostic System Check before using the Symptom
Tables in order to verify that all of the following are true:
|     •  | The control module(s) can communicate via the serial data link. | 
 
Visual/Physical Inspection
|     •  | 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. | 
 
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent
conditions. Refer to 
Testing for Intermittent Conditions and Poor Connections 
 in  Wiring Systems.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order
to diagnose the symptom: