2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 344

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 344

B0785 01

The TCCM detects 3.4 V or greater on the 2 High indicator control circuit when the 2 High indicator is commanded ON.

B0785 06

The TCCM detects 1.6 V or less for 1.5 seconds on the 2 High indicator control circuit when the 2 High indicator is commanded OFF.

Action Taken When the DTC Sets

Normal operation, the SERVICE 4WD indicator is not commanded ON. Driver is informed of fault via bulb inspection.

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

* A TRUE B+ has enough current to light a test light.

* A DIAGNOSTIC B+ is a low current circuit that DOES NOT have enough current to light a test light.

* A short to ground on the 2 High indicator control circuit will cause the 2 High indicator to remain ON at all times.

* An open or high resistance will cause the 2 High indicator to be inoperative during the 2 second bulb check.

* An open in the indicator dimming control circuit will cause the 2 High, 4 High and 4 Low mode indicators to be inoperative during the 2

second bulb check.

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

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

* With key REMOVED - opening a door puts a true B+ on the indicator dimming control circuit, TCSCS X1 pin 4. Other possible voltages are

listed below:

- Door open, key removed - indicator dimming control circuit voltage = true B+.

- Door open, key in, key OFF - indicator dimming control circuit voltage = true B+.

- Door open, key ON, engine OFF - indicator dimming control circuit voltage = diagnostic B+.

- All doors closed, key OFF - indicator dimming control circuit voltage = B+ (high current - enough to light a test light).

- All doors closed, key ON, engine OFF - indicator dimming control circuit voltage = diagnostic B+.

- Key ON, engine OFF. Place a shop light on the DRL sensor. When the DRL sensor commands the headlights OFF, the indicator dimming

control circuit voltage, TCSCS X1 pin 4, will go from a diagnostic B+ to a true B+.

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-49741 - 9 V+ Power Source Harness

* EL-49742 - Battery Voltage B+ and Ground Source Harness

* J 35616 - GM-Approved Terminal Test Kit

Circuit/System Verification