2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 903

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 903

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)

Description and Operation

Transfer Case Description and Operation (See: Transmission and Drivetrain/Transfer Case/Description and Operation/MP 3023/3024-NQH -

Transfer Case/Transfer Case Description and Operation)

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.

Circuit/System Verification

1. Ignition ON, engine OFF.

2. Install a scan tool.

3. Ensure no other ECBM or TCCM codes are set.

瀚慖f any other EBCM or TCCM DTC's are set, diagnose them first.

Circuit/System Testing

1. Engage parking brake.

2. Block rear wheels.

3. Lift front wheels.

4. Key ON, engine OFF. Install scan tool.

5. Transfer case in 2WD HI. Transmission in Neutral.

6. Mechanical binding. - Using the Special Functions capability of the scan tool, engage the front axle. While holding one front tire stationary,

spin the other tire. The front propshaft should turn.

瀚慖f the front propshaft does not turn, inspect the front axle clutch fork for mechanical binding.

7. Wheel speed sensors. - Take the vehicle on a short test drive on a smooth and level road. Using the Data Display function of the ECBM

feature of the scan tool, verify that the front and rear wheel speeds sensors display do not vary or become intermittent.

瀚慖f while driving at a steady speed the RPM values vary or becomes intermittent, check the EBCM for wheel speed DTC's. Wheel speed

DTC's diagnostics are in antilock brake systems.

8. Transfer case encoder motor brake. - Using a scan tool, clear DTC's. Shift the vehicle to 2WD HI. Monitor the transfer case motor amperage

parameter in the Data Display feature of the scan tool. Using the transfer case shift control switch, command the transfer case to the 4WD HI

mode. The transfer case motor amperage should increase while the motor is shifting and then return to 0 amps within 5 seconds or less.

瀚慖f the amperage stays high longer than 5 seconds, this indicates the brake is not holding. Replace the transfer case motor.

9. Transfer case clutch integrity. - Shift the vehicle into 4WD HI and take it for a test drive. Clear the DTC if possible. Monitor front and rear

wheel speeds using the EBCM data display. Under heavy acceleration the front and rear wheel speeds should be similar.

瀚慖f the front wheel speeds are much lower, this indicates a weak clutch and a transfer case tear down and inspection will be required.

10. If all prior evaluations test normal, reprogram the TCCM and perform the ATC Motor Learn procedure in the Special Functions feature of the

scan tool or the Transfer Case High/Low Clutch Reset (See: Transmission and Drivetrain/Transfer Case/Testing and Inspection/Symptom

Related Diagnostic Procedures/MP 3023/3024-NQH - Transfer Case/Transfer Case High/Low Clutch Reset) procedure in the service manual.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.