2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 1244

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 1244

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

瀚慖f 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.

瀚慖f 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

瀚慖f infinite resistance is measured, replace the applicable drive motor generator.

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

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 PIM replacement, setup, and programming.

* Generator Control Module 3-Phase Cable Assembly Replacement ()

* Drive Motor with Generator Assembly Removal - 1st Position (See: Transmission and Drivetrain/Automatic

Transmission/Transaxle/Service and Repair/Overhaul/2ML70 - Automatic Transmission/8. Drive Motor with Generator Assembly Removal -

1st Position)

* Drive Motor with Generator Assembly Removal - 2nd Position (See: Transmission and Drivetrain/Automatic

Transmission/Transaxle/Service and Repair/Overhaul/2ML70 - Automatic Transmission/13. Drive Motor with Generator Assembly Removal

- 2nd Position)

P0A79

DTC P0A78 or P0A79

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

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptor

DTC P0A78

- Drive Motor 1 Inverter Performance

DTC P0A79

- Drive Motor 2 Inverter Performance

Circuit/System Description

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.

Conditions for Running the DTC

* The high voltage contactor relays are closed.

* Ignition voltage is 8-18 volts.