Conditions for Clearing the DTC
* DTC P279D is a Type A DTC.
* When attempting to set HPCM internal DTCs, run the engine for at least 1 minute, and then shut the engine off for 30 seconds. Following
this procedure will allow for a complete HPCM shutdown. Program the HPCM with the latest software version and retest the DTC to see if
the DTC resets.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Diagrams)
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)
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 P279D.
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.
锟斤拷If the scan tool display does not match the transfer case range switch state, repair the transfer case system refer to Diagnostic Starting
Point - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Starting Point - Vehicle).
锟斤拷If the scan tool matches the transfer case range switch state, continue with testing.
2. Program the HPCM with the latest software version and retest for DTCs.
锟斤拷If the DTC resets, replace the HPCM.
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 HPCM replacement, setup, and programming.
P0300
DTC P0300-P0308
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
