All-Wheel Drive Off Indicator Always On
All-Wheel Drive Off Indicator Always On
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.
Circuit/System Description
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.
Reference Information
Schematic Reference
All-Wheel Drive Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information.
Circuit/System Testing
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.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Transfer Case Disassemble (Transfer Case Disassemble)