2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 896

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 896

Circuit/System Description

The transfer case shift control module (TCCM) controls the transfer case actuator lock solenoid. The transfer case actuator lock solenoid is released

by being energized. This is accomplished by grounding the lock solenoid control circuit during range changes, and 4WD Auto mode. Locking

action is applied when power or ground are taken away from the lock solenoid, preventing the transfer case encoder motor (TCEM) from moving.

The system is capable of providing a 2WD HI, 4WD HI and 4WD LO lock-up without the need of additional vehicle power to hold the transfer

case in these positions.

Conditions for Running the DTC

* Ignition ON.

* System voltage 10.5-18 V.

Conditions for Setting the DTC

* The system tests the lock solenoid circuits by checking for unwanted voltage.

* The underhood fuse block supplies B+ on the battery positive voltage circuit and reads the voltage back on the lock solenoid control circuit.

* If the TCCM detects a low voltage return when a high voltage is expected, or a high voltage return when a low voltage is expected, the DTC

is logged.

* The fault must remain current for 1 second to set the DTC.

Action Taken When the DTC Sets

C0321 01 and C0321 04

* Shifts allowed. Clutch engages only if slip is detected.

* The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.

C0321 02 and C0321 08

* Normal operation.

* 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 conditions for setting the DTC are 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

* The default actions for C0321 may set C0306.

* EL-49741 - harness is a good source for 9 V.

* EL-49742 - harness is a good source for B+ and ground.

* The transfer case drain plug is a good source for 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)