Symptoms

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(s) 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 for System Operation.

Visual/Physical Inspection
^ Inspect for aftermarket devices which could affect the operation of the automatic transfer case system. Refer to Checking Aftermarket Accessories in Diagrams/Diagnostic Aids.
^ 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 and Poor Connections in Diagrams/Diagnostic Aids.

Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:
^ Front Axle Will Not Disengage Front Axle Will Not Disengage
^ Front Axle Will Not Engage Front Axle Will Not Engage
^ No Correction for Slip in AWD Mode No Correction For Slip In AWD Mode
^ Range Mode Switch Inoperative Range/Mode Switch Inoperative
^ SERVICE 4WD Message Always On Service 4WD Message Always on
^ SERVICE 4WD Message Inoperative Service 4WD Message Inoperative
^ Switch Indicator Lamps Do Not Light-One or More Switch Indicator Lamps Do Not Light - One or More
^ Switch Indicator Lamps Flash Continuously Switch Indicator Lamps Flash Continuously
^ Switch Indicator Lamps Remain ON - Two or More Switch Indicator Lamps Remain ON - Two or More