2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 329
TCSCS
1. Using the L-BU probe J 35616-65B, connect the memory saver EL-49741 - harness, to the TCSCS as specified below for the LED being
tested. Connecting the harness to the opposite pins will not illuminate the LED.
2. Connect a 9 V battery to the memory saver EL-49741 - harness.
3. Verify that only the indicator being tested illuminates.
瀚慖f the indicator does not illuminate when tested or the incorrect indicator illuminates, replace the TCSCS.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Transfer Case Shift Control Switch Replacement (Without SLT) (See: Powertrain Management/Transmission Control Systems/Sensors and
Switches - Transmission and Drivetrain/Sensors and Switches - Transfer Case/Four Wheel Drive Selector Switch/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for TCSCM replacement, setup, and programming
* 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)
MP 3023/3024-NQH - Transfer Case
DTC B0770
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category
DTC Descriptors
DTC B0770 01
- AWD Indicator Circuit Short to Battery
DTC B0770 06
- AWD Indicator Circuit Short to Ground or Open
Diagnostic Fault Information
Circuit/System Description
The all wheel drive (AWD/4WD Auto) indicator circuit consists of a light emitting diode (LED) feed circuit, a LED and a LED control circuit. The
indicator dimming control circuit is the LED feed circuit and continuously supplies B+ to the 2WD HI, 4WD Auto, 4WD HI, and 4WD LO LEDs.
When the AWD mode has been selected by the driver, the transfer case shift control module (TCCM) provides a ground through the AWD
indicator control circuit illuminating the LED.
The TCCM tests the AWD indicator circuit for unexpected voltage by monitoring the B+ supplied by the BCM on the indicator dimming control
circuit by grounding the AWD indicator control circuit for 2 seconds during the Bulb Test at key ON.
Conditions for Running the DTC
