P0C2B

DTC P0C2B

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0C2B
- Auxiliary Transmission Fluid Pump Control Feedback Circuit

Diagnostic Fault Information






Typical Scan Tool Data






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 3 phase alternating current (ac), motor-driven pump. Two 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 it's own internal circuitry. The ATFP control module does not store it's 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 vehicle is operating in the Autostop hybrid mode.
* Ignition voltage is 8-18 volts.

Conditions for Setting the DTC

The control module has not detected the ATFP diagnostic signal.

Action Taken When the DTC Sets

* DTC P0C2B is a Type B DTC.
* The PIM disables the Autostop hybrid mode.

Conditions for Clearing the DTC

DTC P0C2B is a Type B DTC.

Special Tools

J 38522 Variable Signal Generator

Circuit/System Verification

1. Clear the DTC information.
2. Turn the ignition OFF for 1 minute.
3. Turn the ignition ON.
4. Retest for DTC P0C2B.

Circuit/System Testing

1. Ignition OFF, disconnect ATFP connector 2.
2. Ignition ON, test for battery voltage on the ATFP battery circuit, from ATFP connector 2 terminal A and chassis ground.

^ If less than battery voltage, test the ATFP battery circuit for an open/high resistance. If the circuit tests normal, continue with diagnosis.

Important: If an open ground condition is observed, inspect the 3 phase motor shield circuit and terminal for damage.

3. Test for battery voltage on the ATFP battery circuit from ATFP connector 2 terminal A and the ATFP ground circuit connector 2 terminal C.

^ If less than the specified range, test the ATFP ground circuit for an open/high resistance. If the circuit tests normal, continue with diagnosis.

4. Test for battery voltage on the ATFP ignition circuit from ATFP connector 2 terminal E and the ATFP ground circuit connector 2 terminal C.

^ If less than the specified range, test the ATFP ignition circuit for an open/high resistance. If the circuit tests normal, continue with diagnosis.

5. Test for 4.8-5.2 volts on the Trans. Aux. Oil Pump Diagnostic circuit, from the ATFP connector 2 terminal D and ground.

^ If less than the specified range, test the Trans. Aux. Oil Pump Diagnostic circuit for an open/high resistance. If the circuit tests normal, replace the drive motor generator power inverter control module (PIM).
^ If more than the specified range, test the Trans. Aux. Oil Pump Diagnostic circuit for a short to voltage. If the circuit tests normal, replace the drive motor generator power inverter control module (PIM).

6. Connect the J 38522 variable signal generator to the Trans. Aux. Oil Pump Diagnostic circuit, from the ATFP connector 2 terminal D and ground.
7. Adjust the signal generator to 50% duty cycle @ 250 Hz and observe the Trans. Aux. Pump Actual speed parameter with the scan tool. You should observe 100% on the parameter.

^ If less than 100%, test the Trans. Aux. Oil Pump Diagnostic circuit for a short to 5 V. If the circuit tests normal, replace the drive motor generator power inverter control module (PIM).
^ If 100% is observed, replace the ATFP control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests