2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2071
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)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information.
Circuit/System Verification
1. Start the engine.
2. Let the engine run for 1 minute, then turn the key OFF for 30 seconds.
3. Retest for DTC P279A.
Circuit/System Testing
1. Observe the 4WD Signal in the ECM Data List. The 4WD signal should display Enabled when you shift into 4WD and Disabled when you
shift into 2WD.
瀚慖f the scan tool display does not match the transfer case range switch state, repair the transfer case system. Refer to Diagnostic System
Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System Check - Vehicle).
瀚慖f the scan tool matches the transfer case range switch state, continue with testing.
2. Program the ECM with the latest software version and retest for DTCs.
瀚慖f the DTC resets, replace the ECM.
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 ECM replacement, setup, and programming.
P279B
DTC P279B
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 P279B
- Four Wheel Drive (4WD) Low Range Performance
Circuit/System Description
The engine control module (ECM) monitors the state of the 4WD signal message, if equipped, over the GMLAN communication bus. The ECM
uses this message to determine motor torque required and transmission shifting. There are no external circuits involved.
