* 2WD HI
* AWD/4WD Auto
* 4WD HI
* 4WD LO
* Neutral
Conditions for Running the DTC
* Ignition ON.
* System voltage 10.5-18 V.
Conditions for Setting the DTC
* The system constantly monitors the voltage on switch signal circuit.
* If the system detects a voltage level under 0.38 volts or greater than 4.86 volts for 60 seconds, the DTC is logged.
Action Taken When the DTC Sets
* All shifting is disabled.
* The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.
Conditions for Clearing the DTC
* The TCCM clears the DTC once the condition for setting the DTC is no longer present.
* A history DTC clears after 40 consecutive warm up cycles without a fault present.
* History DTCs can be cleared using a scan tool.
Diagnostic Aids
EL-49742 - harness is a good source for B+ and ground.
Reference Information
Schematic Reference
Transfer Case Control Schematics (See: Transmission and Drivetrain/Transfer Case/Diagrams/Electrical Diagrams/MP 3023/3024-NQH - Transfer
Case)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information.
Special Tools
* EL-49742 - Battery Voltage B+ and Ground Source Harness
* J 35616 - GM-Approved Terminal Test Kit
Circuit/System Verification
1. Key ON, engine OFF.
2. Connect a scan tool.
3. Verify that all mode selections of the transfer case shift control switch (TCSCS) match the following parameters in the Data Display feature of
the scan tool:
* Mode Switch Selected
* Transfer Case Position
* The corresponding Mode Indicator Light
