Circuit/System Description
The accessory power module (APM) monitors its 14-volt circuit when it is enabled for charge or Jump Assist. It requires a minimum voltage on this
circuit in order to begin operation. This DTC sets when the 14-volt circuit in the APM is below this minimum level at the time it is enabled. APM
functions will run only when an APM enable message from the hybrid powertrain control module (HPCM) is active on the high speed hybrid
GMLAN communication circuit.
Conditions for Running the DTC
APM commanded to begin charging or Jump Assist.
Conditions for Setting the DTC
14-volt circuit at the APM is below 6.7 volts when attempting to begin charging or Jump Assist.
Action Taken When the DTC Sets
* DTC P0AFF is a Type C DTC.
* The APM will not allow 14-volt or 42-volt conversions to begin in this condition.
Conditions for Clearing the DTC
* DTC P0AFF is a Type C DTC.
* The 14-volt circuit at the APM is above 6.7 volts.
Diagnostic Aids
The APM is protected from reverse polarity connections by a 200-amp in-line mega-fuse. The output current of the APM is lower than the fuse
rating.
Reference Information
Schematic Reference
Hybrid Controls Schematics ()
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Drive Motor Generator Control Module 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)
* 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)
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 Testing
1. Remove the B+ harness connector X3 at the APM.
2. Connect a test lamp between the 12-volt battery positive and the APM connector X3 at the module.
3. Ignition ON, observe the 12-volt parameter in the APM data list. The parameter should be within 0.5 volt of the actual 12-volt battery
voltage.
锟斤拷If the voltage is not within the specified range, replace the APM.
