If the AWD Off Indicator needs to be turned on the transfer case shift control module sends a signal via the serial data line to the BCM which then sends a message to the instrument panel asking the I/P to command the AWD Off Indicator. The AWD Off Indicator is turned on for three reasons, the transfer case has overheated, the transfer case has lost both rear wheel speeds and vehicle speed, the transfer case has lost the front wheel speeds.

Schematic Reference

All-Wheel Drive Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information.

Important: The instrument panel will display AWD Off once 135°C (275°F) has been met or exceeded. The transfer case temperature sensor DTC will not set until 154°C (309°F) has been met.

1. Check for any transfer case DTCs and diagnose as necessary.
2. Check for any U codes which may indicate the reason why wheel speed or vehicle speeds are missing and diagnose as necessary using the U code diagnostics.
3. Using a scan tool under transfer case data list look at the transfer case oil temperature. If the temperature is at or above 135°C (275°F) determine that the vehicle is not being used beyond its design intent. If this is not the case then the overheat condition may be due to excessively slipping clutches. Allow the transfer case to cool and retest. If the condition persists then disassemble the transfer case and repair as necessary. If an overheating issue is not present go to the next step.
4. Check the ECM and EBCM for DTCs as these modules will likely have set DTCs due to faulty wheel or vehicle speeds. Follow the proper diagnostics and repair as necessary.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Transfer Case Disassemble