Circuit/System Description
The auxiliary transmission fluid pump (ATFP) system supplies the transmission with hydraulic pressure when the vehicle is operating in the
internal combustion engine (ICE) Autostop hybrid mode. The ATFP system consists of a ATFP control module that operates an electric, 12V 3
phase alternating current (ac), motor-driven pump. Two pulse width modulated (PWM) status circuits connect the ATFP control module to the
hybrid powertrain control module (HPCM). The transmission auxiliary oil pump (TAOP) control circuit delivers the HPCM commanded pump
speed to the ATFP control module. The transmission auxiliary oil pump (TAOP) diagnostic circuit supplies the HPCM with the actual pump speed
and also with the operating status of the ATFP control module. The HPCM monitors these circuits for fault conditions.
The ATFP control module inverts 12 v direct current (dc) into 12 v, 3 phase ac current to operate the pump motor.
The ATFP control module monitors the status of the ATFP pump as well as its own internal circuitry. The ATFP control module does not store its
own diagnostic status. Current ignition cycle diagnostic status is reported to the HPCM on the TAOP diagnostic circuit. The diagnostic status
within the ATFP control module is reset at every ignition-off cycle.
Conditions for Running the DTC
* The ignition switch is in the RUN position.
* Ignition voltage is 8-18 volts.
Conditions for Setting the DTC
The control module has not detected the ATFP diagnostic signal for 1.5 seconds.
Action Taken When the DTC Sets
* DTC P0C2B is a Type B DTC.
* The HPCM disables the Autostop hybrid mode.
Conditions for Clearing the DTC
DTC P0C2B is a Type B DTC.
Reference Information
Schematic Reference
Hybrid Controls Schematics ()
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
Special Tools
J 38522 - Variable Signal Generator
