Important: Perform the 
Diagnostic System Check - Vehicle
 before using the symptom tables, in order to verify the following conditions are true:
   •  There are no diagnostic trouble codes (DTCs) present.    •  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 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 . Some symptoms may be caused by loose wiring. Test the system after moving or connecting harnesses, but before replacing parts.
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom: