2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 910

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 910

actuator control circuit, FDAA X1 harness pin B.

4. Using the Engage Front Axle function of the Special Function feature of the scan tool, command the front axle ON and OFF. When

commanded ON the test light should illuminate. When commanded OFF the test light should turn OFF.

瀚慖f the TCCM does not perform as described, replace the TCCM.

5. Go to Circuit/System Verification.

Repair Instructions

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

* 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)

* Four-Wheel Drive Does Not Engage (See: Transmission and Drivetrain/Differential Assembly/Testing and Inspection/Front Drive

Axle/Four-Wheel Drive Does Not Engage)

* Four-Wheel Drive Does Not Disengage (See: Transmission and Drivetrain/Differential Assembly/Testing and Inspection/Front Drive

Axle/Four-Wheel Drive Does Not Disengage)

* Front Drive Axle Actuator Replacement (See: Powertrain Management/Transmission Control Systems/Actuators and Solenoids -

Transmission and Drivetrain/Actuators and Solenoids - Differential/Actuator/Service and Repair)

MP 3010-NP0 - Transfer Case

DTC C0387

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 Descriptor

DTC C0387 59

- Unable to Complete Shift Circuit

Diagnostic Fault Information

Circuit/System Description

The transfer case encoder motor (TCEM) is a bi-directional, permanent magnet, DC motor. When energized, through motor control A or motor

control B, the ground is provided by the opposing motor control circuit and then grounded through the transfer case shift control module (TCCM)

ground circuit, the TCEM, through a series of gears, rotates the transfer case control actuator shaft which moves the transfer case two/four wheel

drive actuator cam and transfer case high/low shift fork to shift the transfer case between the following modes or ranges:

* 2WD HI

* 4WD Auto

* 4WD HI

If the shift lever detent shaft were to bind, or there was a mechanical failure, or motor A control and motor B control were shorted together, the

shift would not be completed. This will cause the DTC to set in order to protect system components from damage.

Conditions for Running the DTC

* Ignition ON

* System voltage 10.5-18 V

Conditions for Setting the DTC