For 1990-2009 cars

Important:

• | Perform the Diagnostic System Check - Vehicle, before using the symptom tables in order to verify that the following statements are true:

- | There are no diagnostic trouble codes (DTCs) set.

- | The control module or 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 .

### Visual/Physical Inspection

• | 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.

### Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections.

### Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• | Front Axle Will Not Engage

• | Front Axle Will Not Disengage

• | Accessory Switch Transfer Case Mode Buttons Inoperative

• | Service Four-Wheel Drive Indicator Always On

• | Service Four-Wheel Drive Indicator Inoperative

• | Accessory Switch Transfer Case Mode Indicator Always On - Two or More

• | Accessory Switch Transfer Case Mode Indicator Flashes, then Returns to Previous Mode

• | Accessory Switch Transfer Case Mode Indicator Inoperative - One or More

• | Accessory Switch Transfer Case Mode Indicator Flashes in 2WD Mode

• | Accessory Switch Transfer Case Mode Indicator Flashes in 4WD High or 4WD Low Mode

• | Accessory Switch Transfer Case Mode Indicator Flashes in 4WD High, 4WD Low, and 2WD Modes

• | Accessory Switch Transfer Case Mode Indicator Flashes in Neutral Mode

• | Transfer Case Popping Noise

| Transfer Case Whine or Rumble Noise

• | Transfer Case Growl or Grinding Noise

• | Transfer Case Clunk in 2HI Only

• | Transfer Case Clunk in 4HI

• | Transfer Case Clunk in 4LO

• | Transfer Case Shudder or Binding

• | Transfer Case Will Not Shift

• | Transfer Case Jumps Out of Gear