The drive motor generator power inverter control module (PIM) contains two motor control modules (MCMs). Each MCM operates its respective drive motor generator based upon hybrid powertrain control module (HPCM) commands. Each MCM controls the speed, direction and output torque of its respective drive motor generator through the sequencing actuation of high current switching transistors called insulated gate bipolar transistors (IGBTs). Each IGBT assembly is monitored for fault conditions.

The MCM detects excessive current flow through the switched portion of the IGBT.

DTCs P0A78 and P0A79 are Type A DTCs.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

1. Clear the DTC information.
2. Turn the ignition OFF for 2 minutes.
3. Turn the ignition ON.
4. Operate the vehicle within the conditions for running and setting.
5. Retest for the DTC.

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks:

•	Identify how to disable high voltage.

•	Identify how to test for the presence of high voltage.

•	Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Failure to follow the procedures exactly as written may result in serious injury or death.
1. Perform the High Voltage Disabling procedure for servicing at the drive motor generator control module cable connections.
2. Remove the 3-phase cable assembly from the PIM distribution box. Refer to Generator Control Module 3-Phase Cable Assembly Replacement.
3. Test the resistance to ground for each phase of the applicable drive motor generator by measuring between the following points with a DMM.

•	Phase U terminal and chassis ground

•	Phase V terminal and chassis ground

•	Phase W terminal and chassis ground

⇒	If infinite resistance is measured, replace the PIM and retest for DTCs. If DTC P0A78 or P0A79 still resets, replace the 3-phase cable assembly and the drive motor generator assembly that corresponds to the set DTC.

⇒	If less than infinite is measured, continue with Circuit/System Testing.

4. Remove the 3-phase cable assembly from the transmission. Refer to Generator Control Module 3-Phase Cable Assembly Replacement. Ensure the terminals are not contacting chassis ground.
5. Retest the resistance to ground for each phase of the 3-phase cable. Measure between the following points with a DMM.

•	Phase U terminal and chassis ground

•	Phase V terminal and chassis ground

•	Phase W terminal and chassis ground

⇒	If infinite resistance is measured, replace the applicable drive motor generator.

⇒	If less than infinite is measured, replace the generator control module 3-phase cable assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.