Hybrid/ev Control System GMC Sierra 2500

Temperature Versus Resistance

Drive Motor 1 and 2 Temperature Sensor

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Diagnostic Code Index

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

The high voltage circuit impact detector sensor utilizes a unidirectional 2-wire circuit. The high voltage circuit impact detector sensor modulates current on the circuit interface to send ID, state of health, and deployment commands to the serial data gateway module. The serial data gateway module serves as a power source and a ground for the high voltage circuit impact detector sensor. When the ignition is turned ON and input power from the serial data gateway module is first detected, the high voltage circuit impact detector sensor responds by performing internal diagnostics and sending an ID to the serial data gateway module. The high voltage circuit impact detector sensor continually communicates status messages to the serial data gateway module. Some applications use multiple high voltage circuit impact detector sensors.

This vehicle does not use crash sensor 2 or 3. These DTCs can only set if the incorrect software is installed in the serial data gateway module.

Conditions for Running the DTC

1. The ignition is ON.
2. The battery voltage is 7.5-18 V.

Conditions for Setting the DTC

B008A 00 or B008B 00

Sensor 2 or 3 is reporting a state-of-health message, but the serial data gateway module is not calibrated to use sensor 2 or 3.

Action Taken When the DTC Sets

The driver information center (DIC) displays the SERVICE HYBRID SYSTEM message.

Conditions for Clearing the DTC

1. A current DTC clears when the malfunction is no longer present.
2. The DIC message turns OFF when the DTC passes.
3. A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Circuit/System Verification

Verify that DTC B008A or B008B is not set.

1. If any of the DTCs are set, program the serial data gateway module. If any of the DTCs reset, replace the serial data gateway module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for serial data gateway module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Typical Scan Tool Data

Hybrid Crash Sensor 1

The high voltage circuit impact detector sensor utilizes a unidirectional 2-wire circuit. The high voltage circuit impact detector sensor modulates current on the circuit interface to send ID, state of health, and collision status to the serial data gateway module. The serial data gateway module serves as a power source and a ground for the high voltage circuit impact detector sensor. When the ignition is turned ON and input power from the serial data gateway module is first detected, the high voltage circuit impact detector sensor responds by performing internal diagnostics and sending an ID to the serial data gateway module. The high voltage circuit impact detector sensor continually communicates status messages to the serial data gateway module

1. The ignition is ON.
2. The battery voltage is 7.5-18 V.

B009F 00

The serial data gateway module is not programmed to use high voltage circuit impact detector sensor 1.

B009F 11

The high voltage circuit impact detector sensor signal circuit is shorted to voltage for 2.5 seconds.

B009F 12

The high voltage circuit impact detector sensor signal circuit is shorted to ground for 2.5 seconds.

B009F 39

The serial data gateway module has not received a valid state of health message from the high voltage circuit impact detector sensor for 2.5 seconds.

B009F 3A

The wrong high voltage circuit impact detector sensor has been installed.

B009F 4A

The serial data gateway module calibration does not match the vehicle configuration.

B009F 73

The serial data gateway module has received invalid serial data from the high voltage circuit impact detector sensor.

The driver information center (DIC) displays the SERVICE HYBRID SYSTEM message.

1. A current DTC clears when the malfunction is no longer present.
2. The DIC message turns OFF when the DTC passes.
3. A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Diagnostic Aids

1. The high voltage circuit impact detector sensor has many different internal configurations in the same external package. Ensure that the correct sensor part number is installed with the correct software programmed in the serial data gateway module.
2. Turn the ignition OFF for 1 minute before using a scan tool to clear the DTC from the serial data gateway module. If the ignition is not OFF for 1 minute, the DTC may not clear.

Reference Information

Schematic Reference

Data Communication Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC B009F 00, B009F 4A, or B009F 73 is not set. If the DTC is set, program the serial data gateway module. If the DTC resets, replace the serial data gateway module.
2. Verify the serial data gateway module is programmed with the correct software calibration. If the correct software is not installed, program the serial data gateway module.
3. Ignition ON, observe the scan tool Hybrid Crash Sensor 1 parameter. The reading should be No Crash. If not No Crash, refer to Circuit/System Testing below.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the high voltage circuit impact detector sensor.
2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the serial data gateway module.
3. Connect a DMM, set on a manual setting that can read 12 V with the MIN/MAX function enabled, between the signal circuit terminal 1 and ground.
4. Ignition ON, wait 10 seconds, The DMM reading should be less than 1.0 V. If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the serial data gateway module.
5. Verify the DMM MAX reading is greater than 6.0 V. If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the serial data gateway module.
6. If all circuits test normal, test or replace the high voltage circuit impact detector sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «High Voltage Circuit Impact Detection Sensor Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
2. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for serial data gateway module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Run, ON, and START Power signals connect the serial data gateway module along with numerous other modules to the vehicle 12-volt system through a fused relay in the fuse block - underhood. This relay is closed by the Body Control Module (BCM) based on the key being in either the RUN or START position.

The ignition voltage is between 9-16 V.

B1453 01

The ignition switch is in the ACC position.

B1453 06

The ignition switch is in the RUN position.

B1453 01

The RUN, ON, and START circuits are greater than 2.5 volts.

B1453 06

The RUN, ON, and START circuits are less than 2.5 volts.

DTC B1453 is a Type C DTC.

DTC B1453 is a Type C DTC.

B1453 01

The RUN, ON, and START circuits are less than 2.5 volts.

B1453 06

The RUN, ON, and START circuits are more than 2.5 volts.

Many controllers such as the drive motor generator power inverter module, transmission control module (TCM), and inflatable restraint sensing and diagnostic module will set a DTC for a problem with the RUN, ON, and START power voltage circuits. Confirm that they do not have DTCs before only investigating the serial data gateway module.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the X2 harness connector at the K56 serial data gateway module, verify that a test lamp does not illuminate between the ignition circuit terminal 20 and ground. If the test lamp illuminates, test the signal circuit terminal 20 for a short to voltage.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 20 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
3. If all circuits test normal, replace the K56 serial data gateway module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Serial Data Gateway Module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hybrid powertrain control module continuously monitors the system voltage on the Ignition voltage circuits. The hybrid powertrain control module is located within the drive motor generator power inverter module and is not serviced separately. Lower than normal voltage may be inadequate to operate the control module or sensors properly.

The ignition is ON.

The hybrid powertrain control module detects system voltage is 10 V or less for 5 out of 6 seconds.

DTC P0562 is a Type C DTC.

DTC P0562 is a Type C DTC.

Observe the driver information center messaging that would indicate the electrical system requires service.

Inspect for the following conditions

1. Loose or damaged battery terminals.
2. Loose or corroded connections at the drive motor generator power inverter module.
3. Loose or corroded connections at the accessory DC power control module.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Engine running, accessories OFF, measure and record the battery voltage with a DMM. The battery voltage should be 12.5-15.5 V. If not within the specified range, or the Charge Indicator light is ON, refer to «DC Power Conversion Test»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Observe the scan tool hybrid powertrain control module voltage. The reading should be 12.5-15.5 V.

1. Ignition OFF, remove the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) , and disconnect the X4 harness connector at the K1 Accessory DC Power Control Module.
2. Test for less than 1 ohm between the ground circuit terminal X4 bare ground strap and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Disconnect the X1 connector of the T6 drive motor generator control module. Ignition ON, verify that a test lamp illuminates between the control module voltage circuit terminals listed below and ground: Terminal 6 Terminal 7 If the test lamp does not illuminate, test the control module voltage circuit for a short to ground or an open/high resistance.
4. Ignition ON, verify that a test lamp illuminates between the control module voltage circuit terminal 20 and ground. If the test lamp does not illuminate, test the control module voltage circuit for a short to ground or an open/high resistance.
5. If all circuits test normal, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hybrid powertrain control module continuously monitors the system voltage on the Ignition voltage circuits. The hybrid powertrain control module is located within the drive motor generator power inverter module and is not serviced separately. A higher than normal voltage may cause the control module or sensors to operate improperly.

The ignition is ON.

The hybrid powertrain control module detects system voltage is greater than 18 V for 5 out of 6 seconds.

DTC P0563 is a Type C DTC.

DTC P0563 is a Type C DTC.

1. Observe the driver information center messaging that would indicate the electrical system requires service.
2. A battery charger may have set this DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Engine running, accessories OFF, observe the scan tool hybrid powertrain control module ignition voltage parameter. The reading should be less than 15.5 V.

1. If not within the specified value, or the Charge Indicator light is ON, go to «DC Power Conversion Test»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .

1. Ignition OFF, remove the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Disconnect the T6 drive motor generator power inverter module X1 connector.
3. Ignition ON, verify that a test lamp illuminates between the control module voltage circuit terminal 20 and ground. If the test lamp illuminates, replace the T6 drive motor generator power inverter module.
4. Inspect for an external condition that may have caused a high 12 V circuit condition such as a battery charger.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is an internal fault detection of the hybrid powertrain control module. The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. This fault is handled inside the hybrid powertrain control module and no external circuits are involved.

1. The ignition is ON.
2. The system voltage is at least 7 V.

The control module has detected an internal malfunction.

1. DTCs P0601, P0602, P0603, P0604, P0606 and P062F are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0601, P0602, P0603, P0604, P0606 and P062F are Type A DTCs.

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTC P0562 is not set. If DTC is set, refer to «DTC P0562»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module monitors its ability to read and write to the memory. The hybrid powertrain control module processor monitors the data to verify that the indicated torque calculation is correct. The hybrid powertrain control module is located within the drive motor generator power inverter module and is not serviceable separately.

P061A

1. The system voltage is 8-18 V.
2. Regenerative braking torque is greater than 0 N.m.

P061B

1. The system voltage is 8-18 V.
2. Any output or brake torque is present.

P061A

The control module has detected the internal software calculation for regenerative braking torque has an error of greater than 100 N.m.

P061B

The control module has detected a torque calculation error.

1. DTCs P061A and P061B are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P061A and P061B are Type A DTCs.

A reduced hybrid battery power condition is most noticeable during high electrical loads such as Autostop to Autostart transitions. Inspect for hybrid battery DTCs or conditions that would reduce available hybrid battery power such as

1. Hybrid Battery Module undervoltage / P0AFA and various DTCs
2. Hybrid Battery Module overvoltage / various DTCs
3. Hybrid Battery Module voltage variation / P0AFA, P0BBD
4. Hybrid Battery overtemperature / P0C32
5. Hybrid Battery exposure to extreme cold

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup, and programming.
2. «Drive Motor Battery Replacement and Shipping Preparation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__drive-motor-battery-replacement-and-shipping) for Hybrid Battery replacement.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules and a hybrid powertrain control module. Each motor control module utilizes a 5 V reference power supply for internal circuit needs. This fault is handled inside the drive motor generator power inverter module and no external circuits are involved. The motor control modules and the hybrid powertrain control module are part the drive motor power inverter module and are not serviced separately.

1. The ignition is ON.
2. The system voltage is 8-18 V.

The control module has detected an internal malfunction.

1. DTCs P0642, P0643, P0652 and P0653 are Type A DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0642, P0643, P0652 and P0653 are Type A DTCs.

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to communication integrity conditions between the engine control module (ECM) and the hybrid powertrain control module. The hybrid powertrain control module monitors a state of health message that the ECM transmits to verify the ECM is functioning properly. The hybrid powertrain control module is part the drive motor power inverter module and is not serviced separately.

The system voltage is 8-18 V.

The hybrid powertrain control module does not detect a valid state of health message from the ECM.

1. DTC P06AF is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P06AF is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Verify that ECM DTC P0606, P0A1D is not set.

1. If the DTC is set, Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .

1. Ignition OFF, remove the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Disconnect the T6 drive motor generator power inverter module X1 connector and the ECM X3 connector.
3. Test for less than 1 ohms between the serial data circuits listed below: T6 drive motor generator power inverter module X1 connector terminal 10 and K20 ECM X3 connector terminal 33 T6 drive motor generator power inverter module X1 connector terminal 11 and K20 ECM X3 connector terminal 53 If greater than the specified range, test the serial data circuit for an open/high resistance condition. If the circuit tests normal, replace the K20 ECM.
4. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM or Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules and a hybrid powertrain control module. The motor control modules share an internal 15 V reference power supply in order to operate the drive motor sensors processors. This fault is handled inside the drive motor generator power inverter module and no external circuits are involved. The motor control modules and the hybrid powertrain control module are part the drive motor power inverter module and are not serviced separately.

1. The ignition is ON.
2. The system voltage is 8-18 V.

P06B1 or P06B4

The reference voltage is less than 12 V for 1 second.

P06B2 or P06B5

The reference voltage is greater than 18 V for 1 second.

1. DTCs P06B1, P06B2, P06B4 and P06B5 are Type B DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P06B1, P06B2, P06B4 and P06B5 are Type B DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is a fault detection of the drive motor generator power inverter module's internal motor control modules. This fault is handled inside the drive motor generator power inverter module, no external circuits are involved. The motor control modules are part of the drive motor generator power inverter module, and are not serviced separately.

1. The ignition is ON.
2. The system voltage is 8-18 V.

The control module has detected an internal malfunction.

1. DTCs P0A1B and P0A1C are Type A DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0A1B and P0A1C are Type A DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module.

1. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module contains several microprocessors. The hybrid powertrain control module is part of the drive motor generator power inverter control module, and is not serviced separately. This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module and each motor control module utilize a programmable logic device to perform certain input and output functions. At ignition ON, the programmable logic device expects to communicate with the hybrid powertrain control module and both motor control modules. The programmable logic device will communicate to motor control module 1 over an internal communication circuit when it has established communications with the hybrid powertrain control module. Motor control module 1 will communicate to the engine control module (ECM) over the serial data circuit if the programmable logic device has not established communication with the hybrid powertrain control module.

1. The Ignition is ON.
2. the system voltage is at least 8 V and no more than 18 V.

The control module has detected an internal hybrid powertrain control module malfunction.

DTC P0A1D is a Type A DTC.

DTC P0A1D is a Type A DTC.

An intermittent loss of battery power to the drive motor generator power inverter module may set this DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that a U-code DTC is not set. If a U-code DTC is set, repair them first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Ignition OFF, disconnect the 12 V battery. Refer to «Battery Negative Cable Disconnection and Connection»(/gmc/sierra-2500/2012-2012/remont/charging-system/#engine-electrical-battery-hybrid-hp2) .
3. Wait 2 minutes.
4. Connect the 12 V battery. Refer to «Battery Negative Cable Disconnection and Connection»(/gmc/sierra-2500/2012-2012/remont/charging-system/#engine-electrical-battery-hybrid-hp2) .
5. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Motor Control Module Motor 1/2 Temperature Sensor

The motor temperature sensor is a non-serviceable part of the drive motor generator assembly. The motor temperature sensor is a thermistor, or a resistor that changes value when the temperature changes. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases, and as the temperature decreases, the resistance increases. The motor control module supplies a 5 V reference signal to the sensor and measures the voltage drop in the circuit. When the motor is cold, the sensor resistance is high and the motor control module detects high signal voltage. As the motor temperature increases, the resistance of the sensor decreases, which lowers the signal voltage.

P0A2B and P0A31

1. DTCs P0A2C, P0A2D, P0AEF, P0AF0, P0BD3, P0BD4, P0BDD, P0BDE are not set.
2. Ignition ON after the engine has been OFF for at least 6 hours.
3. Average of phase U, V, W inverter temperatures is greater than -12°C (+10°F).
4. Motor temperature is greater than -40°C (-40°F).

P0A2C, P0A2D, P0A32 and P0A33

The ignition is ON.

P0A2B and P0A31

The average of the three motor phase sensor temperatures and the motor temperature are not within 28°C (50°F) of each other at ignition ON for 3 seconds.

P0A2C and P0A32

Motor temperature sensor signal is less than 0.29 V for 3 seconds.

P0A2D and P0A33

Motor temperature sensor signal is greater than 4.42 V when drive motor generator torque is greater than 20 N.m (14.75 lb ft) for 3 seconds.

1. DTCs P0A2B-P0A2D, P0A31-P0A33 are Type B DTCs.
2. The hybrid powertrain control module requests the SERVICE HYBRID SYSTEM message to display on the drive information center.

DTCs P0A2B-P0A2D, P0A31-P0A33 are Type B DTCs.

1. The motor temperature sensor can be damaged by excessive electric current. Test the sensor for an open condition whenever a short to voltage condition is observed.
2. Test the X176 transmission 24-way connector for proper terminal contact whenever an open or high resistance circuit condition is observed.
3. The hybrid powertrain control module motor temperature scan tool parameter display will default to 120°C (248°F) when an open or shorted signal circuit is detected.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

DT-48493 Jumper Harness, 24 terminal

For equivalent regional tools, refer to Special Tools .

P0A2B and P0A31

1. Allow the vehicle to cool to ambient temperature by leaving the ignition OFF for at least 6 hours.
2. Ignition ON, observe Motor 1 temperature, Motor 2 temperature, and phase U, V, W inverter temperature scan tool parameters. The Motor 1 Temperature, Motor 2 Temperature, and phase U, V, W inverter temperature parameters should be within 28°C (50°F) of each other and ambient temperature.

P0A2C, P0A2D, P0A32, and P0A33

Ignition ON, observe the motor control modules motor temperature scan tool parameter.

1. The motor temperature parameter should be between 0.29 V and 4.42 V.

1. Ignition OFF, disconnect the transmission X176 24-way harness connector.
2. Connect DT-48493 jumper harness.
3. Ignition ON, test the jumper harness side for less than 8 ohms between the low reference circuit terminals listed below and ground for the appropriate drive motor generator: Drive motor 1 low reference circuit terminal 19 Drive motor 2 low reference circuit terminal 23 If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
4. Ignition ON, verify the scan tool motor temperature sensor parameter is greater than 4.42 V. If less than the specified value, test the motor temperature sensor signal circuit for a short to ground. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
5. Install a 3-amp fused jumper wire between the signal circuit terminal and the low reference circuit terminal listed below for the appropriate drive motor generator. Verify the scan tool motor temperature sensor parameter is less than 0.29 V: Drive motor 1 terminals 13 and 19 Drive motor 2 terminals 22 and 23 NOTE: If a short to voltage is found, test the motor temperature sensor for damage. If greater than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
6. Ignition OFF, connect the DT-48493 jumper harness to the X176 transmission 24-way connector at the transmission. Measure and record the resistance between the sensor signal and low reference terminals. Compare the actual sensor and circuit resistance to the expected sensor resistance. Refer to «Temperature Versus Resistance»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__temperature-versus-resistance) . If the resistance is near the expected value, test the transmission internal harness signal circuit for a short to ground. If the circuit tests normal, replace the M15 drive motor generator. If the resistance is not near the expected value, test the transmission internal harness signal and low reference circuits for an open or shorted together condition. If the circuits test normal, replace the M15 drive motor generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup, and programming
2. «Transmission Control Wiring Harness Extension Harness Removal»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle) for Drive Motor with Generator Assembly replacement
4. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle) for Drive Motor with Generator Assembly replacement

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The transmission contains two electric motor generators. The drive motor generators are cooled by the transmission fluid. Hot fluid exits the drive motor generator housing and flows to the transmission cooler supply line. The supply line connects to the cooler. From the cooler, the fluid returns through the oil cooler return line and enters the lubrication circuits. After lubricating the internal components, the fluid returns to the oil pan. The motor temperature sensor is part of the drive motor generator assembly and is not serviced separately.

DTC P0A2B is not set.

The motor temperature sensor is greater than 200°C (392°F) for 3 seconds and has not fallen below 135°C (275°F).

1. DTC P0A2F is a Type B DTC.
2. The hybrid powertrain control module commands the engine into derate mode.
3. Autostop is disabled.

DTC P0A2F is a Type B DTC.

1. The driver information center, if equipped, will display 'TRANSMISSION HOT- Idle Engine' when the transmission fluid temperature is greater than 132°C (270°F) for 10 minutes.
2. Ask about the customer's driving habits, trailer towing, etc.
3. Ensure the engine cooling system is functioning normally.
4. The hybrid powertrain control module will reduce drive motor generator torque at temperatures greater than 160°C (320°F). Drive motor generator torque is reduced to zero if the temperature reaches 190°C (374°F).

Description and Operation

Electronic Component Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC P0A2C is not set. If DTC P0A2C is set, Refer to «DTC P0A2B-P0A2D or P0A31-P0A33»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Ignition ON, observe the scan tool ECM engine coolant temperature (ECT) parameter in freeze frame data. The reading should be below 125°C (257°F). If the ECT was above 125°C (257°F) when the DTC set, go to «Symptoms - Engine Cooling»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) and correct that concern first.
3. Ignition ON, observe the scan tool motor 1 temperature and motor 2 temperature parameters in freeze frame data. The reading should be above 200°C (392°F). If greater than the specified value, go to «Automatic Transmission Overheating»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-diagnostic-information-and-procedures) . If the transmission tests normal, replace M15A drive motor 1 generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Drive Motor with Generator Assembly Removal - 1st Position

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The transmission contains two electric motor generators. The drive motor generators are cooled by the transmission fluid. Hot fluid exits the drive motor generator housing and flows to the transmission cooler supply line. The supply line connects to the cooler. From the cooler, the fluid returns through the oil cooler return line and enters the lubrication circuits. After lubricating the internal components, the fluid returns to the oil pan. A non-serviceable motor temperature sensor is located in each drive motor generator assembly.

DTC P0A31 is not set.

The motor temperature sensor is greater than 200°C (392°F) for 3 seconds, and has not fallen below 135°C (275°F).

1. DTC P0A35 is a Type B DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P0A35 is a Type B DTC.

1. The driver information center, if equipped, will display 'TRANSMISSION HOT- Idle Engine' when the transmission fluid temperature is more than 132°C (270°F) for 10 minutes.
2. Ask about the customer's driving habits, trailer towing, etc.
3. Ensure the engine cooling system is functioning normally.
4. The hybrid powertrain control module will reduce drive motor generator torque at temperatures greater than 160°C (320°F). Drive motor generator torque is reduced to zero if the temperature reaches 190°C (374°F).

Description and Operation

Electronic Component Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC P0A31 is not set. If DTC P0A31 is set, Refer to «DTC P0A2B-P0A2D or P0A31-P0A33»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Ignition ON, observe the scan tool ECM engine coolant temperature (ECT) parameter in freeze frame data. The reading should be below 125°C (257°F). If the ECT was above 125°C (257°F) when the DTC set, go to «Symptoms - Engine Cooling»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) and correct that concern first.
3. Ignition ON, observe the scan tool motor 1 temperature and motor 2 temperature parameters in freeze frame data. The reading should be above 200°C (392°F). If greater than the specified value, go to «Automatic Transmission Overheating»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-diagnostic-information-and-procedures) . If transmission tests normal, replace M15B drive motor 2 generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Drive Motor with Generator Assembly Removal - 2nd Position

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed and direction of the drive motor generator rotor based upon the signals of the resolver-type position sensor. The position sensor contains a drive coil, two driven coils, and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the motor control module outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The motor control module then monitors the two driven coil circuits for a return signal. The position of the irregular metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coils signals allows the motor control module to determine the exact position, speed and direction of the drive motor generator rotor. The position sensor is a non-serviceable part of the drive motor generator.

The ignition is ON.

P0C52, P0C5C

Circuit voltage less than 0.5 V.

P0C53, P0C5D

Circuit voltage greater than 3.0 V.

P0A3F

The motor control module cannot determine the motor position based upon the sensor signals.

P0A40

The motor control module detects a degraded motor position sensor signal.

P1B03

The motor control module cannot track the motor position based upon the sensor signals.

1. DTCs P0A3F, P0A40, P0C52, P0C53, P0C5C, P0C5D, and P1B03 are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0A3F, P0A40, P0C52, P0C53, P0C5C, P0C5D, and P1B03 are Type A DTCs.

1. The drive motor generator position sensor circuits operate at very low current. Extreme care must be taken when probing terminals and manipulating harnesses.
2. The sensor circuit loops are a twisted pair with each pair covered in a foil shield. The shield circuits outside of the transmission are grounded to a stud on the drive motor generator power inverter module assembly.
3. The drive motor generator position sensor harness circuits are shielded. Improperly grounded shield circuits may cause inaccurate sensor signals.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

1. «WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index)
2. «WIRING SYSTEMS AND POWER MANAGEMENT - INLINE HARNESS CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views-index)

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

DT-48493 Jumper Harness

For equivalent regional tools, refer to Special Tools .

1. Ignition OFF, disconnect the X176 harness connector at the transmission.
2. Install the DT-48493 jumper harness to the vehicle harness side only.
3. Ignition ON, test for 0.8-1.4 V between the terminals listed below and ground: Terminal 10 Terminal 11 Terminal 12 Terminal 14 If not within the specified range, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal replace the T6 power inverter module.
4. Ignition ON, test for 6.5-7.5 V between the terminals listed below and ground: Terminal 8 Terminal 9 If not within the specified range, test the signal circuits for a short to voltage, short to ground or an open/high resistance. If the circuits test normal replace the T6 power inverter module.

Component Testing

1. Verify that DTCs P1AF0, P1AF2, P1B43, P1B44, P1B0B, or P1B0C is not set. If DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Ignition OFF, disconnect the X176 harness connector at the transmission.
3. Install the DT-48493 jumper harness to the transmission side only.
4. Test for 7.0-9.0 ohms between the AC terminal 8 and the AC terminal 9. If not within the specified range, test the transmission control wiring harness extension harness circuits for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal replace the M15A drive motor with generator assembly.
5. Test for 20-23 ohms between the signal terminal 12 and the signal terminal 14. If not within the specified range, test the transmission control wiring harness extension harness circuits for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal replace the M15A drive motor with generator assembly.
6. Test for 23-26 ohms between the signal terminal 10 and the signal terminal 11. If not within the specified range, test the transmission control wiring harness extension harness circuits for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal replace the M15A drive motor with generator assembly.
7. Test for greater than 10, 000 ohms between the terminals listed below and ground: Terminal 8 Terminal 9 Terminal 10 Terminal 11 Terminal 12 Terminal 14 If less than the specified value, test the transmission control wiring harness extension harness circuit for a short to ground. If the circuit tests normal replace the M15A drive motor with generator assembly.
8. Test for infinite resistance between the terminals listed below: Terminals 8 and 10 Terminals 8 and 12 Terminals 10 and 12 If less than the specified value, test the transmission control wiring harness extension harness circuits for a short between the circuits. If the circuits test normal replace the M15A drive motor with generator assembly.
9. If the test passed refer to Circuit/System Testing below.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
2. «Transmission Control Wiring Harness Extension Harness Removal»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module Assembly replacement, setup and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed and direction of the drive motor generator rotor based upon the signals of the resolver-type position sensor. The position sensor contains a drive coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the motor control module outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The motor control module then monitors the two driven coil circuits for a return signal. The position of the irregular metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coils signals allows the motor control module to determine the exact position, speed and direction of the drive motor generator rotor. The position sensor is a non-serviceable part of the drive motor generator.

The ignition is ON.

P0A45

The system voltage is 9-18 V

P0C57 or P0C61

Circuit voltage less than 0.5 V.

P0C58 or P0C62

Circuit voltage greater than 3.0 V.

P0A45

The motor control module cannot determine the motor position based upon the sensor signals.

P0A46

The motor control module detects a degraded motor position sensor signal.

P1B04

The motor control module cannot track the motor position based upon the sensor signals.

1. DTCs P0A45, P0A46, P0C57, P0C58, P0C61, P0C62, and P1B04 are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0A45, P0A46, P0C57, P0C58, P0C61, P0C62, and P1B04 are Type A DTCs.

1. The drive motor generator position sensor circuits operate at very low current. Extreme care must be taken when probing terminals and manipulating harnesses.
2. The sensor circuit loops are a twisted pair with each pair covered in a foil shield. The shield circuits outside of the transmission are grounded to a stud on the drive motor generator power inverter module assembly.
3. The drive motor generator position sensor harness circuits are shielded. Improperly grounded shield circuits may cause inaccurate sensor signals.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

1. «WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index)
2. «WIRING SYSTEMS AND POWER MANAGEMENT - INLINE HARNESS CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views-index)

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

DT-48493 Jumper Harness

For equivalent regional tools, refer to Special Tools .

1. Ignition OFF, disconnect the X176 harness connector at the transmission.
2. Install the DT-48493 jumper harness to the vehicle harness side only.
3. Ignition ON, test for 0.8-1.4 V between the terminals listed below and ground: Terminal 17 Terminal 18 Terminal 20 Terminal 21 If not within the specified range, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal replace the T6 power inverter module.
4. Ignition ON, test for 6.5-7.5 V between the terminals listed below and ground: Terminal 15 Terminal 16 If not within the specified range, test the signal circuits for a short to voltage, short to ground or an open/high resistance. If the circuits test normal replace the T6 power inverter module.

1. Verify that DTCs P1AF0, P1AF2, P1B43, P1B44, P1B0B, or P1B0C is not set. If DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Ignition OFF, disconnect the X176 harness connector at the transmission.
3. Install the DT-48493 jumper harness to the transmission side only.
4. Test for 7.0-9.0 ohms between the AC terminal 15 and the AC terminal 16. If not within the specified range, test the transmission control wiring harness extension harness circuits for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal replace the M15A drive motor with generator assembly.
5. Test for 20-23 ohms between the signal terminal 20 and the signal terminal 21. If not within the specified range, test the transmission control wiring harness extension harness circuits for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal replace the M15A drive motor with generator assembly.
6. Test for 23-26 ohms between the signal terminal 17 and the signal terminal 18. If not within the specified range, test the transmission control wiring harness extension harness circuits for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal replace the M15A drive motor with generator assembly.
7. Test for greater than 10, 000 ohms between the terminals listed below and ground: Terminal 15 Terminal 16 Terminal 17 Terminal 18 Terminal 20 Terminal 21 If less than the specified value, test the transmission control wiring harness extension harness circuit for a short to ground. If the circuit tests normal replace the M15B drive motor with generator assembly.
8. Test for infinite resistance between the terminals listed below: Terminals 15 and 17 Terminals 15 and 20 Terminals 17 and 20 If less than the specified value, test the transmission control wiring harness extension harness circuits for a short between the circuits. If the circuits test normal replace the M15B drive motor with generator assembly.
9. If the test passed refer to Circuit/System Testing below.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
2. «Transmission Control Wiring Harness Extension Harness Removal»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module Assembly replacement, setup and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules. Each motor control module operates its respective drive motor generator based upon hybrid powertrain control module commands. Each motor control modules 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. Each insulated gate bipolar transistor assembly is monitored for fault conditions. The motor control modules are part of the drive motor generator power inverter module and are not serviced separately.

1. The high voltage contactor relays are closed.
2. The ignition voltage is 8-18 volts.

The motor control module detects excessive current flow through the switched portion of the insulated gate bipolar transistor.

1. DTCs P0A78 and P0A79 are Type A DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0A78 and P0A79 are Type A DTCs.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, clear DTC; Turn the ignition OFF for 2 minutes. Turn ignition ON, Operate vehicle within conditions for running and setting DTC. If the DTC resets, go to Circuit/System Testing below.

1. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
2. Remove the 3-phase cable assembly from the drive motor generator power inverter module distribution box. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
3. Test for infinite resistance between the Phase Terminals listed below and ground for each phase of the appropriate M15 drive motor generator: Drive Motor 1 X7 terminal phase U X8 terminal phase V X9 terminal phase W Drive Motor 2 X10 terminal phase U X11 terminal phase V X12 terminal phase W If less than the specified range, disconnect the 3-phase cable assembly from the transmission. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ensure the terminals are not contacting chassis ground. Test for infinite resistance between Phase Terminals and ground. If the circuit tests normal, replace the M15 drive motor generator. If less than infinite resistance is measured, replace the generator control module 3-phase cable assembly.
4. If infinite resistance is measured, replace the T6 drive motor generator power inverter module.

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

1. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for drive motor generator power inverter module replacement, setup, and programming.
2. «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
3. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
4. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power module continuously monitors its 14-volt circuit during charge or jump assist. This DTC sets when the 14-volt circuit in the accessory DC power module drops below a set level. Accessory DC power module functions will run only when an accessory DC power module enable message from the hybrid powertrain control module is active on the serial data circuit.

Accessory DC power control module is charging or in Jump Assist.

14-volt circuit less than 10.0 V during charge or Jump Assist.

1. DTC P0A8D is a Type C DTC.
2. The engine control module (ECM) will command the charge indicator and or warning message to be illuminated on the instrument panel cluster and the driver information center, if equipped.
3. The accessory DC power control module will shutdown 14-volt conversions.

DTC P0A8D is a Type C DTC.

1. A charging system malfunction may cause variances in system voltage and set voltage related DTCs. Refer to «DC Power Conversion Test»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. A poor ground connection between the Accessory DC Power Control Module and chassis ground may result in excess current passing through the 42-volt ground circuit connector X2 terminal 2 from the electric power steering circuit resulting in DTC P0A8D.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Perform DC Power Conversion Test before performing Circuit/System Testing.

1. Ignition OFF, disconnect the X3 14-volt harness connector and the X2 42-volt harness connector at the K1 accessory DC power control module. Make sure neither harness connector contacts chassis ground.
2. Test for less than 1.0 ohm between the K1 accessory DC power control module and chassis ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminals listed below and ground: Connector X3 Terminal A Connector X1 Terminal 3 If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. If all circuits test normal, replace the K1 accessory DC power control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Accessory DC Power Module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power module continuously monitors its 14 volt circuit during charge or jump assist. This DTC sets when the 14 volt circuit in the accessory DC power control module rises above a set level. Accessory DC power control module functions will run only when an accessory DC power control module enable message from the hybrid powertrain control module is active on the serial data circuit.

Accessory DC power control module is charging or in Jump Assist.

1. 14 volt circuit is more than 16.5 V while charging.
2. 14 volt circuit is more than 16.0 V in Jump-Assist.

1. DTC P0A8E is a Type C DTC.
2. The accessory DC power control module will shutdown charging or Jump Assist.

1. 14 volt circuit is below 16.3 V while charging.
2. 14 volt circuit is below 15.8 V in Jump-Assist.

1. A possible cause of this DTC could be overcharging with a battery charger or jump starting.
2. A high voltage value in multiple modules indicates a concern in the charging system.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Engine Running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6-15.0 volts.

1. If not within the specified range, refer to «DC Power Conversion Test»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .

Ignition ON, command the K1 accessory DC power control module set point control UP and DOWN with a scan tool. Observe the 12 V battery voltage with a DMM. The 12 V battery voltage should follow the voltage set point command.

1. If the voltage is not the specified value, replace the K1 accessory DC power control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Accessory DC Power Control Module replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This vehicle does not use a 12V starter motor to crank the internal combustion engine. A much more powerful 300V drive motor generator located within the transmission is utilized to crank the engine. The 300V drive motor generator can rotate the engine to operating speed (800 RPM) within just a few hundred milliseconds. The hybrid powertrain control module can detect a condition where the engine is cranking but does not start or has stalled.

Drive motor generator 1 is cranking the engine.

The hybrid powertrain control module detects that CKP engine speed has not risen above the commanded cranking speed indicating the engine has failed to start, or the hybrid powertrain control module detects CKP engine speed has fallen below a specific minimum speed indicating the engine has stalled.

DTC P0AB9 is a Type A DTC.

Cranks But Does Not Start

When the ignition is turned to Crank, the hybrid powertrain control module will command drive motor generator 1 to rotate the engine. The drive motor will continue to rotate the engine at a specific RPM until the engine starts and causes increased engine RPM. The hybrid powertrain control module will cease engine rotation if an increase in engine RPM is not observed after several seconds. This function may have the appearance of a start/stall condition.

Engine Stall

If a stall occurs after a successful engine start, the hybrid powertrain control module will recognize the drop in engine RPM and command drive motor generator 1 to maintain engine RPM in an attempt to restart the engine. Drive motor generator 1 will continue to rotate the engine until the hybrid powertrain control module commands it to stop. The engine may be rotated for many minutes after the actual engine stall condition occurred and is typically stopped only after the hybrid battery state of charge gets too low. This function may have the appearance of a running engine.

DTC P0AB9 is a Type A DTC.

Any condition that causes the engine to stall and/or not start may set this DTC. Possible conditions include

1. Fuel conditions such as low level, low pressure, or contamination.
2. Engine conditions such as low compression.
3. Restricted exhaust or air intake systems.

Always inspect for DTCs that would cause an engine stall and/or no start condition. Because the hybrid system can rotate the engine at high RPM, stall and cranks-but-does-not-start conditions act differently than a non-hybrid vehicle. Refer to Action Taken When the DTC Sets.

Turn the ignition to Crank. The engine should start and run.

1. If the engine fails to start, diagnose the engine system. Refer to «Engine Cranks But Does Not Run»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-dtc-p0351-to-dtc-p3449-and-diagnostic-information-and-procedures) .
2. If the engine starts and runs the condition is intermittent.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is an internal fault detection of the drive motor generator power inverter module. This fault is handled inside the drive motor generator power inverter module and no external circuits are involved.

P0AEE, P0AF3, P0BD2, P0BD7, P0BDC, and P0BE1

1. Ignition ON after the ignition has been OFF for 6 hours.
2. Temperature average of the inverter phase temperature sensors is greater than 12°C (10°F).
3. Motor temperature sensor is greater than -40°C (-40°F).
4. DTCs P0AEF, P0AF0, P0BD3, P0BD4, P0BDD, P0BDE, P0A2C, and P0A2D are not set.

P0AEF, P0AF4, P0BD3, P0BD8, P0BDD, and P0BE2

The ignition is ON.

P0AF0, P0AF5, P0BD4, P0BD9, P0BDE, and P0BE3

1. The ignition is ON.
2. Motor temperature is greater than -40°C (-40°F). If motor temperature is less than -40°C (-40°F) at Ignition ON, the drive motor must operate at greater than 20 N.m (14.75 lb ft) for a cumulative time of 1.5 minutes before the DTC will run.

P0AEE, P0AF3, P0BD2, P0BD7, P0BDC, and P0BE1

1. A 15°C (27°F) difference is observed between the individual inverter phase temperature sensor and the average of all the inverter phase temperatures.
2. The above condition is present for 4 seconds.

P0AEF, P0AF4, P0BD3, P0BD8, P0BDD, and P0BE2

The inverter phase temperature sensor is greater than 125°C (275°F) for 3 seconds.

P0AF0, P0AF5, P0BD4, P0BD9, P0BDE, and P0BE3

The inverter phase temperature sensor is less than -40°C (-40°F) for 3 seconds.

1. DTCs P0AEE, P0AEF, P0AF0, P0AF3, P0AF4, P0AF5, P0BD2, P0BD3, P0BD4, P0BD7, P0BD8, P0BD9, P0BDC, P0BDD, P0BDE, P0BE1, P0BE2 AND P0BE3 are Type B DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0AEE, P0AEF, P0AF0, P0AF3, P0AF4, P0AF5, P0BD2, P0BD3, P0BD4, P0BD7, P0BD8, P0BD9, P0BDC, P0BDD, P0BDE, P0BE1, P0BE2 AND P0BE3 are Type B DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power module controls the energy flowing between the high voltage, 300-volt, DC and low voltage, 14-volt, DC to support the vehicles accessories and charge the 12-volt battery. The accessory DC power control module receives a 14-volt enable command from the hybrid powertrain control module over the serial data communication circuit. Accessory DC power module functions will run only when the accessory DC power module enable is active on the serial data communication circuit.

The Ignition is ON.

Accessory DC power control module heat plate temperature is greater than 105°C (221°F).

1. DTC P0AF7 is a Type C DTC.
2. The accessory DC power control module will shut down charging or Jump Assist.
3. The accessory DC power control module will also set DTC P1A8B 11 42-Volt Inverter Temperature High to limit power to the electric power steering.

DTC P0AF7 is a Type C DTC.

This DTC could be caused by a possible power electronics cooling system failure due to the following

1. Restricted radiator air flow or coolant fans inoperative.
2. Restricted power electronics coolant flow or contaminated coolant.
3. Inoperative power electronics cooling system water pump.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the scan tool accessory DC power control module heat plate temperature and engine coolant temperature (ECT) parameters in freeze frame data. The accessory DC power control module heat plate temperature reading should be less than 105°C (221°F). If the accessory DC power control module heat plate temperature parameter reading was greater than 105°C (221°F) and the engine coolant temperature (ECT) was greater than 125°C (257°F) in freeze frame data, refer to «Symptoms - Engine Cooling»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) and correct that concern first.
2. Inspect for proper coolant level in the hybrid cooling system reservoir. If coolant level is low refer to «Hybrid Cooling System Loss of Coolant»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system__hybrid-cooling-system-loss-of-coolant) .
3. Inspect hybrid cooling hoses for pinches or obstructions. If a concern is found, repair or replace hoses as necessary.
4. Inspect the hybrid cooling system radiator for debris or obstruction. Refer to «Engine Overheating»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) . If a concern is found, repair or replace the restricted or damaged components as necessary.
5. Inspect for proper operation of all hybrid system coolant pumps. Refer to «Hybrid Cooling System Overheating (Electrical)»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system) . If a concern is found, repair or replace the coolant pumps as necessary.
6. Command the cooling fans through all operating speeds. If the cooling fans do not operate in all speeds, refer to «Cooling Fan Inoperative (without HP2)»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling Fan Inoperative (with HP2)»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling Fan Inoperative (Diesel)»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
7. Separate the T6 drive motor generator power inverter module from the K1 accessory DC power control module. Inspect the T6 drive motor generator power inverter module and K1 accessory DC power control module cooling surfaces for excessive corrosion or contamination restriction. Refer to «Drive Motor Generator Power Inverter Module Removal and Installation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__drive-motor-generator-power-inverter-module) . If a corrosion or contamination is found, clean the K1 accessory DC power control module and drive motor generator power inverter module cooling surfaces. If corrosion is severe enough to prevent cleaning of the cooling surfaces replace the K1 accessory DC power control module. Replace K1 accessory DC power control module if no concerns are found.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Generator Control Module Coolant Pump Replacement (Left)»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system) , «Generator Control Module Coolant Pump Replacement (Right)»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system)
2. «Hybrid Cooling System Leak Test»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system__hybrid-cooling-system-leak-test)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Accessory DC Power Module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power control module 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 accessory DC power control module is below this minimum level at the time it is enabled. Accessory DC power control module functions will run only when an accessory dc power module enable message from the hybrid powertrain control module is active on the serial data circuit.

Accessory DC power control module commands charging or Jump Assist.

14-volt circuit at the accessory DC power control module is less than 6.7 V when commanding charging or Jump Assist.

1. DTC P0AFF is a Type C DTC.
2. The accessory dc power control module will not allow 14-volt or 42-volt conversions to begin in this condition.

1. DTC P0AFF is a Type C DTC.
2. The 14-volt circuit at the accessory DC power control module is greater than 6.7 V.

The accessory DC power control module is protected from reverse polarity connections by a 200-amp in-line mega-fuse. The output current of the accessory DC power control module is lower than the fuse rating.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Perform Battery Inspection/Test .

1. Disconnect the B+ harness connector X3 at the K1 accessory DC power control module.
2. Connect a test lamp between the 12-volt battery positive post and the accessory DC power control module connector X3 at the module.
3. Ignition ON, observe the 12-volt parameter in the accessory DC power control module data list. The parameter should be within 0.5 volt of the actual 12-volt battery voltage. If the voltage is not within the specified range, replace the accessory DC power control module.
4. Ignition OFF, Remove the positive connection at the 12-volt battery.
5. Measure the resistance between the X3 harness connector and the battery positive connection. If the resistance is greater than 1.0 ohm, repair the high resistance condition in the 12-volt circuit. If the resistance is less than 1.0 ohm, replace the battery positive cable - control module to auxiliary Bussed Electrical Center.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «200 Amp Mega Fuse and Auxiliary Electrical Center 12VDC Junction Block Replacement»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
2. «Battery Positive Cable Replacement (12V Battery to Auxiliary BEC)»(/gmc/sierra-2500/2012-2012/remont/charging-system/#engine-electrical-battery-hybrid-hp2)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for accessory DC power control module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is an internal fault detection of the drive motor generator power inverter module. This fault is handled inside the drive motor generator power inverter module and no external circuits are involved.

The control module runs the program to detect an internal fault when the Hybrid wake-up circuit is active.

The control module has detected an internal malfunction.

1. DTCs P0BE6, P0BE7, P0BE8, P0BEA, P0BEB, P0BEC, P0BEE, P0BEF, P0BF0, P0BF2, P0BF3, P0BF4, P0BF6, P0BF7, P0BF8, P0BFA, P0BFB and P0BFC are Type B DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0BE6, P0BE7, P0BE8, P0BEA, P0BEB, P0BEC, P0BEE, P0BEF, P0BF0, P0BF2, P0BF3, P0BF4, P0BF6, P0BF7, P0BF8, P0BFA, P0BFB and P0BFC are Type B DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules and the hybrid powertrain control module. Each motor control module operates its respective drive motor based upon hybrid powertrain control module commands. Each motor control modules 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. Each drive motor generator operates utilizing 3-phase AC electricity. Each insulated gate bipolar transistors operates a single phase of the drive motor generator. Each phase is individually identified as U, V and W. Each motor control modules monitors the current of each phase in order to detect drive motor generator power inverter module over current conditions.

Because all the motor generator phase circuits are electrically joined together, they should each flow about the same amount of current. The motor control modules perform a mathematical calculation to verify that the phase current sensors are accurate. If the U-V-W phase current sensors indicate about the same amount of phase current, the sum of the calculation should be near zero. If the U-V-W phase currents are not similar, this DTC will set.

The high voltage contactor relays are closed.

The sum of the 3 phase current sensors is greater than 75 A.

1. DTCs P0BFD and P0BFE are Type A DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0BFD and P0BFE are Type A DTCs.

Schematic Reference

Hybrid Controls Schematics

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, clear DTC; Turn the ignition OFF for 2 minutes. Turn ignition ON, Operate vehicle within conditions for running and setting DTC. If the DTC resets, go to Circuit/System Testing below.

1. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) .
2. Ignition OFF, disconnect the appropriate 3-phase cable assembly from the T6 drive motor generator power inverter module listed below. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Drive Motor 1 X7 phase U X8 phase V X9 phase W Drive Motor 2 X10 phase U X11 phase V X12 phase W
3. Test for infinite resistance to circuit terminals listed below and ground: Drive Motor 1 X7 terminal phase U X8 terminal phase V X9 terminal phase W Drive Motor 2 X10 terminal phase U X11 terminal phase V X12 terminal phase W If disconnect the 3-phase cable assembly from the T12 automatic transmission assembly. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ensure the terminals are not contacting chassis ground. Test the circuits for short to ground. If the circuits test normal, replace the M15 drive motor.
4. Replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
2. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
4. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules and the hybrid powertrain control module. Each motor control module operates its respective drive motor generator based upon drive motor generator power inverter module commands. Each motor control modules 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. Each drive motor generator operates utilizing 3-phase AC electricity. Each insulated gate bipolar transistor operates a single phase of the drive motor generator. Each phase is individually identified as U, V and W. Each motor control module monitors the current of each phase in order to detect drive motor generator power inverter module overcurrent conditions. The motor control modules are part of the drive motor generator power inverter module, and are not serviced separately.

The hybrid wakeup circuit is active.

One or more phase currents are greater than 680 A.

1. DTCs P0C01 and P0C04 are Type A DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0C01 and P0C04 are Type A DTCs.

Schematic Reference

Hybrid Controls Schematics

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, clear DTC; Turn the ignition OFF for 2 minutes. Turn ignition ON, Operate vehicle within conditions for running and setting DTC. If the DTC resets, go to Circuit/System Testing below.

1. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) .
2. Ignition OFF, disconnect the appropriate 3-phase cable assembly from the T6 drive motor generator power inverter module listed below. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Drive Motor 1 X7 phase U X8 phase V X9 phase W Drive Motor 2 X10 phase U X11 phase V X12 phase W
3. Test for infinite resistance to circuit terminals listed below and ground: Drive Motor 1 X7 terminal phase U X8 terminal phase V X9 terminal phase W Drive Motor 2 X10 terminal phase U X11 terminal phase V X12 terminal phase W If disconnect the 3-phase cable assembly from the T12 automatic transmission assembly. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ensure the terminals are not contacting chassis ground. Test the circuits for short to ground. If the circuits test normal, replace the M15 drive motor.
4. Replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup, and programming.
2. «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
3. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
4. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Each drive motor is controlled by a motor control module. The drive motor utilize 3 phase AC electricity. The drive motor stator coil is comprised of three phase circuits. The phase circuits are identified as phase U, phase V, and phase W. The U-V-W phase circuits are connected in a wye configuration. This means each phase is connected at a single, central point. The motor control modules monitor a current sensor connected to each drive motor generator phase. The current sensor is part of the drive motor assembly and is not serviced separately. The motor control module is part of the drive motor generator power inverter module and is not serviced separately.

1. The Hybrid Wakeup circuit is active.
2. The motor control module has applied current to the drive motor generator.

The motor control module detects at least one U-V-W phase current sensor is less than 9 A.

1. DTCs P0C05 and P0C08 are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0C05 and P0C08 are Type A DTCs.

Schematic Reference

Hybrid Controls Schematics

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, clear DTC; Turn the ignition OFF for 1 minute. Turn ignition ON, Operate vehicle within conditions for running and setting DTC. If the DTC resets, go to Circuit/System Testing below.

1. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator power inverter module cable connections.
2. Remove the 3-phase cable assembly from the drive motor generator power inverter module distribution box. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
3. Test for infinite resistance between the Phase Terminals listed below and ground for each phase of the appropriate M15 drive motor generator: Drive Motor 1 X7 terminal phase U X8 terminal phase V X9 terminal phase W Drive Motor 2 X10 terminal phase U X11 terminal phase V X12 terminal phase W If less than the specified range, disconnect the 3-phase cable assembly from the transmission. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ensure the terminals are not contacting chassis ground. Test for infinite resistance between Phase Terminals and ground. If the circuit tests normal, replace the M15 drive motor generator. If less than infinite resistance is measured, replace the generator control module 3-phase cable assembly.
4. If infinite resistance is measured, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup, and programming.
2. «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
3. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle) .
4. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle) .

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is an internal fault detection of the drive motor generator power inverter module. This fault is handled inside the drive motor generator power inverter module and no external circuits are involved.

The inverter self test is complete.

The control module does not detect voltage at the insulated gate bi-polar transistor bias supply.

1. DTCs P0C0B and P0C0E are Type A DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0C0B and P0C0E are Type A DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules and the hybrid powertrain control module. Each motor control modules operates its respective drive motor generator based upon hybrid powertrain control module commands. Each motor control modules 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. Each drive motor generator operates utilizing 3 phase AC. Each insulated gate bipolar transistor operates a single phase of the drive motor generator. Each phase is individually identified as U, V and W. Each motor control modules monitors the temperature of each phase in order to detect drive motor generator power inverter module overtemperature conditions.

P0C11-P0C16

The Hybrid Wakeup circuit is active.

P0C11

P0AEE, P0AEF, and P0AF0 are not set.

P0C12

P0BD2, P0BD3, and P0BD4 are not set.

P0C13

P0BDC, P0BDD and P0BDE are not set.

P0C14

P0AF3, P0AF4, and P0AF5 are not set.

P0C15

P0BD7, P0BD8, and P0BD9 are not set.

P0C16

P0BE1, P0BE2, and P0BE3 are not set.

The phase temperature has exceeded 91°C (196°F) and has not fallen below 85°C (185°F) for 5 seconds.

1. DTCs P0C11, P0C12, P0C13, P0C14, P0C15 and P0C16 are Type B DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P0C11, P0C12, P0C13, P0C14, P0C15 and P0C16 are Type B DTCs.

Description and Operation

1. «Drive Motor Generator Control Module Description and Operation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
2. «Drive Motor Generator Control Module Cooling System Description and Operation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Ignition ON, observe the scan tool ECM engine coolant temperature (ECT) parameter in freeze frame data. The reading should be below 125°C (257°F). If the ECT was above 125°C (257°F) when the DTC set, go to «Symptoms - Engine Cooling»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) and correct that concern first.
2. Inspect for proper coolant level in the hybrid cooling system reservoir. If coolant level is low refer to «Generator Control Module Cooling System Draining and Filling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system__generator-control-module-cooling-system-draining) .
3. Inspect the hybrid cooling system radiator for debris or obstruction. If a concern is found, repair or replace the restricted or damaged components as necessary.
4. Inspect for proper operation of all hybrid system coolant pumps. Refer «Hybrid Cooling System Overheating (Electrical)»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system) . If a concern is found, repair or replace the coolant pumps as necessary.
5. Command the cooling fans through all operating speeds. If the cooling fans do not operate in all speeds, refer to «Cooling Fan Inoperative (without HP2)»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling Fan Inoperative (with HP2)»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) , «Cooling Fan Inoperative (Diesel)»(/gmc/sierra-2500/2012-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
6. If the above inspections do not identify a concern, disassemble the T6 drive motor generator power inverter module and inspect the drive motor generator power inverter module cooling surface for excessive corrosion or contamination restriction. Refer to «Drive Motor Generator Power Inverter Module Removal and Installation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__drive-motor-generator-power-inverter-module) . If corrosion or contamination is found, clean the drive motor generator power inverter module cooling surface or replace the T6 drive motor generator power inverter module as necessary.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed and direction of the drive motor generator based upon the signals of the resolver-type position sensor. The position sensor, or resolver, contains a drive coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the motor control module outputs a 7 V alternating current, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The motor control module then monitors the two driven coil circuits for a return signal. The position of the irregular shaped metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coil signals allows the motor control modules to determine the exact position, speed and direction of the drive motor generator.

The position sensor is part of the drive motor generator and is not serviced separately.

Offset is the relationship between the position sensor and the drive motor generator output shaft. Whenever the ignition is cycled to OFF, and the motor control modules attempts to learn the offset of the drive motor position sensor. The motor control modules will attempt to learn the position at hybrid wake-up, ignition ON only if no valid offset value has ever been learned. This condition would normally occur only after a motor control module reprogramming event.

Condition 1, 2, 3 and 4

1. Hybrid wake-up signal is active.
2. The motor control module has not previously learned a valid drive motor position sensor offset value.

Condition 2

Motor speed is less than 20 RPM.

Condition 1

Position sensor offset value not learned because drive motor speed is greater than 50 RPM.

Condition 2

Position sensor offset value not learned because hybrid battery voltage is less than 192 V.

Condition 3

Position sensor offset value not learned because drive motor phase to phase current difference is less than 15 A.

Condition 4

Position sensor offset value not learned because offset learn value is greater than 25 degrees.

DTCs P0C17 and P0C18 are Type B DTCs.

DTCs P0C17 and P0C18 are Type B DTCs.

Schematic Reference

Hybrid Controls Schematics

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTCs P0A40, P0A45, P0A46, P0A78, P0A79, P0A3F, P0C05, P0C08, P0C0B, P0C0E, P0C4E, P0C4F, P0C52, P0C53, P0C57, P0C58, P0C61, P0C62, P0C5C, P0C5D, P1B03, P1B04 or P1B0D is not set. If DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Drive motor 1 controlled by motor control module 1. The motor control module constantly monitors the requested torque and the delivered torque of its respective drive motor generator. Motor control module 1 is part of the drive motor generator power inverter module and is not serviced separately.

1. The system voltage is 8-18 V.
2. Drive motor generator is commanded to develop torque.

The motor control 1 module has detected that drive motor 1 torque is not being delivered as expected.

1. DTC P0C19 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P0C19 is a Type A DTC.

Because the engine and drive motor 1 are mechanically connected through a planetary gear set, an engine condition that requires drive motor 1 to consume excessive current while trying to rotate the engine may cause this DTC to set such as

1. Extreme acceleration from stop may cause this DTC to be set in history.
2. Extreme braking during regeneration may cause this DTC to be set in history.
3. Seized or binding engine
4. Seized or binding accessory drive belt

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify the engine is not seized or binding. If the engine is seized or binding, refer to «Symptoms - Engine Mechanical»(/gmc/sierra-2500/2012-2012/remont/mechanical/#engine-mechanical-hybrid-hp2-60l-lz1-diagnostic-information-and-procedures) .
2. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Each drive motor generator is controlled by a motor control module. The motor control module constantly monitors the requested torque and the delivered torque of its respective drive motor generator. Motor Control Module is part of the drive motor generator power inverter module assembly and is not serviced separately.

1. The system voltage is 8-18 V.
2. Drive motor 2 is commanded to develop torque.

The motor control module has detected that drive motor generator torque is not being delivered as expected.

1. DTC P0C1A is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P0C1A is a Type A DTC.

1. Extremely hard acceleration from stop may cause this DTC to be set in history.
2. Extremely hard braking during regeneration may cause this DTC to be set in history.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Verify that DTCs P0C1A is not set.

1. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Aux. Trans. Fluid Pump Fault Status 1

Aux. Trans. Fluid Pump Fault Status 2

The auxiliary transmission fluid pump system supplies the transmission with hydraulic pressure when the vehicle is operating in the internal combustion engine Autostop hybrid mode. The auxiliary transmission fluid pump system consists of a auxiliary transmission fluid pump control module that operates an electric, 12V 3 phase alternating current (AC), motor-driven pump. Two pulse width modulated (PWM) status circuits connect the auxiliary transmission fluid pump control module to the hybrid powertrain control module. The transmission auxiliary oil pump control circuit delivers the hybrid powertrain control module commanded pump speed to the auxiliary transmission fluid pump control module. The transmission auxiliary oil pump diagnostic circuit supplies the hybrid powertrain control module with the actual pump speed and also with the operating status of the auxiliary transmission fluid pump control module. The hybrid powertrain control module monitors these circuits for fault conditions.

The auxiliary transmission fluid pump control module inverts 12V direct current (DC) into 12v 3 phase ac current to operate the pump motor.

The auxiliary transmission fluid pump control module monitors the status of the auxiliary transmission fluid pump motor/pump as well as its own internal circuitry. The auxiliary transmission fluid pump control module does not store its own diagnostic status. Current ignition cycle diagnostic status is reported to the hybrid powertrain control module over the transmission auxiliary oil pump diagnostic circuit. The diagnostic status within the auxiliary transmission fluid pump control module is reset at every ignition-off cycle.

1. The ignition voltage is 8-18 volts.
2. The ignition is ON.

The hybrid powertrain control module has not detected an auxiliary transmission fluid pump control module diagnostic signal for at least 1.5 seconds.

1. DTC P0C2B is a Type B DTC.
2. The drive motor generator power inverter module disables the Autostop function of the hybrid system.

DTC P0C2B is a Type B DTC.

The engine harness connector for the auxiliary transmission fluid pump control module and the mating connector for the transmission auxiliary pump motor can be improperly connected to each other. All of the following conditions may be observed if the improper connectors are mated together

1. DTC P0C2B
2. The TRANS PUMP 60A fuse will open
3. BCM DTC B1433
4. Air conditioning system does not blow cold air

The auxiliary transmission fluid pump control module monitors the status of the auxiliary transmission fluid motor/pump as well as its own internal circuitry. This control module does not store its own diagnostic status. Diagnostic status for the current ignition cycle is reported to the hybrid powertrain control module. The diagnostic status within the auxiliary transmission fluid pump control module is reset at every ignition-off cycle.

To determine if a fault is present, while commanding the aux. trans. fluid pump speed to 50 percent observe the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 1 and the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 2 parameters. Both readings should display No Fault.

Below is the fault status that will be reported if a fault condition is current.

No PWM Response

This fault status indicates the hybrid powertrain control module does not detect the automatic transmission auxiliary fluid pump Control Feedback circuit signal.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Signal Generator

For equivalent regional tools, refer to Special Tools .

1. Verify that DTC B1433 is not set. If the DTC is set, refer to «DTC B1433»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures) .
2. Ignition ON, engine OFF, command the Aux. Trans. Pump Speed to 50 percent with the scan tool, maintain pump operation for at least 60 seconds while observing the hybrid powertrain control module aux. trans. fluid pump actual and the aux. trans. fluid pump commanded parameter. The actual parameter should remain within 10 percent of commanded value during the 60 second test. If not within the specified range, refer to Circuit System Testing below.
3. While commanding the aux. trans. fluid pump speed to 50 percent observe and record the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 1 and the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 2 parameters. Both readings should display No Fault. If the reading displays No PWM Response, refer to Circuit System Testing below.

1. Ignition OFF, disconnect the X1 harness connector at the K6 automatic transmission auxiliary fluid pump control module.
2. Test for less than 5 ohms between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Verify that a test lamp illuminates between the B+ circuit terminal A and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal E and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
5. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal D and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K6 automatic transmission auxiliary fluid pump control module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
6. Ignition OFF. Disconnect the X1 harness connector at the K6 automatic transmission auxiliary fluid pump control module. Connect the J 38522 variable signal generator to the harness connector signal circuit terminal D and ground.
7. Adjust the signal generator to 50 percent duty cycle @ 250 Hz and observe the Trans. Aux. Pump Actual parameter with the scan tool. The scan tool should display 100 percent. If the reading is less than 100 percent, test the signal circuit for a short to voltage. If the circuit tests normal replace the T6 drive motor generator power inverter module.
8. If the reading is 100 percent, replace the K6 automatic transmission auxiliary fluid pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module or Automatic Transmission Auxiliary Fluid Pump Control Module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules. Each motor control module controls and monitors its respective drive motor generator based upon commands from the hybrid powertrain control module. In order for the hybrid powertrain control module to monitor the internal combustion engine speed, motor control module 1 is electrically connected to the crankshaft position sensor signal and reference circuits. The motor control module 1 engine speed information is broadcast to the hybrid powertrain control module over an internal drive motor generator power inverter module communication circuit. Additionally, the hybrid powertrain control module receives engine speed over serial data that is broadcast by the engine control module (ECM) and is based upon the ECM connection to the crankshaft position sensor.

A drive motor generator position sensor is monitored by each motor control module. Each motor control module monitors the angular position, speed and direction of its respective drive motor generator based upon the signals of the resolver-type position sensor.

The hybrid powertrain control module mathematically calculates what engine speed should be based upon the current transmission ratio and the drive motor generator speeds indicated by the drive motor generator position sensors.

The hybrid powertrain control module compares this mathematically calculated engine speed to the sensor-derived serial data ECM engine speed signal and motor control module signal engine speed. If the drive motor generator position sensor speeds are correct, the mathematical equation should accurately calculate engine speed. If the mathematical calculation for engine speed does not match the sensor-derived engine speed, a drive motor position speed sensor error is assumed and this DTC will set.

Condition 1

1. The ignition is ON.
2. Ignition voltage is greater than 6 volts.
3. ECM or motor control module 1 crankshaft position sensor engine speed is less than 1500 RPM.

Condition 2

1. The ignition is ON.
2. Ignition voltage is greater than 6 volts.
3. ECM or motor control module 1 crankshaft position sensor engine speed is greater than 1500 RPM.

Condition 1

The difference between ECM or motor control module 1 crankshaft position sensor engine speed and hybrid powertrain control module calculated engine speed is greater than 1499 RPM for 1 second.

Condition 2

The difference between ECM or motor control module 1 crankshaft position sensor engine speed and hybrid powertrain control module calculated engine speed is greater than 249 RPM for 1 second.

1. DTC P0C2F is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

1. DTC P0C2F is a Type A DTC.
2. ECM or motor control module 1 crankshaft position sensor engine speed is greater than 500 RPM and the difference from hybrid powertrain control module calculated engine speed is less than 151 RPM.

Any condition that allows the engine or drive motor speed sensors to indicate their actual speed incorrectly may cause this DTC to set.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify the engine is not seized or binding. If the engine is seized or binding, refer to «Symptoms - Engine Mechanical»(/gmc/sierra-2500/2012-2012/remont/mechanical/#engine-mechanical-hybrid-hp2-60l-lz1-diagnostic-information-and-procedures) .
2. Verify that DTC P0335 or P0336 is not set. If the DTC P0335 or P0336 is set, Refer to «DTC P0335»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-dt-p0010-to-dtc-p0341) , or «DTC P0336»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-dt-p0010-to-dtc-p0341) .
3. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, Refer to «DTC P0A3F, P0A40, P0C52, P0C53, P0C5C, P0C5D, or P1B03»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed and direction of the drive motor generator rotor based upon the signals of the resolver-type position sensor. The position sensor contains a drive coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the motor control module outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The motor control module then monitors the two driven coil circuits for a return signal. The position of the irregular metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coils signals allows the motor control module to determine the exact position, speed and direction of the drive motor generator rotor. The position sensor is a non-serviceable part of the drive motor generator.

Offset is the relationship between the position sensor and the drive motor generator output shaft. When the ignition turned OFF, the motor control module attempts to learn the offset of the drive motor position sensor.

1. The ignition is cycled OFF.
2. Drive motor generator speed is less than 20 RPM.

The position sensor offset exceeds 25 degrees during the learning process.

1. DTC P0C4E is a Type C DTC.
2. The motor control module uses the last learned valid position sensor offset.

DTC P0C4E is a Type C DTC.

1. The drive motor generator position sensor circuits operate at very low current. Just a few ohms of additional circuit resistance may cause position sensor signal degradation. Extreme care must be taken when probing terminals and manipulating harnesses.
2. The sensor circuit loops are twisted pair with each pair covered in a foil shield. The shield circuits outside of the transmission are grounded to a stud on the drive motor generator power inverter module assembly.
3. Ensure the drive motor generator position sensor harness shield circuits are properly grounded prior to testing.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

1. «WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index)
2. «WIRING SYSTEMS AND POWER MANAGEMENT - INLINE HARNESS CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views-index)

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Special Tools

DT-48493 Jumper Harness

For equivalent regional tools, refer to Special Tools .

1. Verify that DTC P0A3F, P0A40, P0C52, P0C53, P0C5C, P0C5D, or P1B03 are not set. If any of the DTCs are set, refer to «DTC P0A3F, P0A40, P0C52, P0C53, P0C5C, P0C5D, or P1B03»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Ignition OFF, disconnect the X176 harness connector at the transmission.
3. Install the DT-48493 jumper harness to the harness side only.
4. Disconnect the X1 harness connector at the T6 drive motor generator power inverter module.
5. Test for less than 1 ohms between the terminals listed below: Terminals 8 and 56 Terminals 9 and 55 Terminals 10 and 54 Terminals 11 and 53 Terminals 12 and 52 Terminals 14 and 51 If greater that the specified range, test the signal circuit for an open/high resistance.
6. If all circuits test normal, replace the M15A drive motor with generator assembly.

1. Ignition OFF, disconnect the X176 harness connector at the transmission.
2. Install the DT-48493 jumper harness to the transmission side only.
3. Test for 7.0-9.0 ohms between the AC terminal 8 and the AC terminal 9. If less than the specified range, test the transmission control wiring harness extension harness circuits for a short between the AC circuits. If the circuits test normal replace the drive motor with generator assembly. If greater than the specified range, test each transmission control wiring harness extension harness AC circuits for an open. If the circuits test normal replace the M15A drive motor with generator assembly.
4. Test for 20-23 ohms between the signal terminal 12 and the signal terminal 14. If less than the specified range, test the transmission control wiring harness extension harness circuits for a short between the signal circuits. If the circuits test normal replace the M15A drive motor with generator assembly. If greater than the specified range, test each transmission control wiring harness extension harness signal circuits for an open. If the circuits test normal replace the M15A drive motor with generator assembly.
5. Test for 23-26 ohms between the signal terminal 10 and the signal terminal 11. If less than the specified range, test the transmission control wiring harness extension harness circuits for a short between the signal circuits. If the circuits test normal replace the M15A drive motor with generator assembly. If greater than the specified range, test each transmission control wiring harness extension harness signal circuits for an open. If the circuits test normal replace the M15A drive motor with generator assembly.
6. Test for greater than 7 ohms between the terminals listed below and ground: Terminal 8 Terminal 9 Terminal 10 Terminal 11 Terminal 12 Terminal 14 If less that the specified value, test the transmission control wiring harness extension harness circuit for a short to ground. If the circuit tests normal replace the M15A drive motor with generator assembly.
7. Test for infinite resistance between the terminals listed below: Terminals 8 and 10 Terminals 8 and 12 Terminals 10 and 12 If less that the specified value, test the transmission control wiring harness extension harness circuits for a short between the circuits. If the circuits test normal replace the M15A drive motor with generator assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
2. «Transmission Control Wiring Harness Extension Harness Removal»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module Assembly replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed and direction of the drive motor generator rotor based upon the signals of the resolver-type position sensor. The position sensor contains a drive coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the motor control module outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The motor control module then monitors the two driven coil circuits for a return signal. The position of the irregular metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coils signals allows the motor control module to determine the exact position, speed and direction of the drive motor generator rotor. The position sensor is a non-serviceable part of the drive motor generator.

Offset is the relationship between the position sensor and the drive motor generator output shaft. When the ignition turned OFF, the motor control module attempts to learn the offset of the drive motor position sensor.

1. The ignition is cycled OFF.
2. Drive motor generator speed is less than 20 RPM.

The position sensor offset exceeds 25 degrees during the learning process.

1. DTC P0C4F is a Type C DTC.
2. The motor control module uses the last learned valid position sensor offset.

DTC P0C4F is a Type C DTC.

1. The drive motor generator position sensor circuits operate at very low current. Just a few ohms of additional circuit resistance may cause position sensor signal degradation. Extreme care must be taken when probing terminals and manipulating harnesses.
2. The sensor circuit loops are twisted pair with each pair covered in a foil shield. The shield circuits outside of the transmission are grounded to a stud on the drive motor generator power inverter module assembly.
3. Ensure the drive motor generator position sensor harness shield circuits are properly grounded prior to testing.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

1. «WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index)
2. «WIRING SYSTEMS AND POWER MANAGEMENT - INLINE HARNESS CONNECTOR END VIEWS - INDEX»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views-index)

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Special Tools

DT-48493 Jumper Harness

For equivalent regional tools, refer to Special Tools .

1. Verify that DTC P0A45, P0A46, P0C57, P0C58, P0C61, P0C62, or P1B04 are not set. If any of the DTCs are set, refer to «DTC P0A45, P0A46, P0C57, P0C58, P0C61, P0C62, or P1B04»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Ignition OFF, disconnect the X176 harness connector at the transmission.
3. Install the DT-48493 jumper harness to the harness side only.
4. Disconnect the X1 harness connector at the T6 drive motor generator power inverter module.
5. Test for less than 1 ohms between the terminals listed below: Terminals 15 and 49 Terminals 16 and 48 Terminals 17 and 47 Terminals 18 and 46 Terminals 20 and 45 Terminals 21 and 44 If greater that the specified range, test the signal circuit for an open/high resistance.
6. If all circuits test normal, replace the M15B drive motor with generator assembly.

1. Ignition OFF, disconnect the X176 harness connector at the transmission.
2. Install the DT-48493 jumper harness to the transmission side only.
3. Test for 7.0-9.0 ohms between the AC terminal 15 and the AC terminal 16. If less than the specified range, test the transmission control wiring harness extension harness circuits for a short between the AC circuits. If the circuits test normal replace the M15B drive motor with generator assembly. If greater than the specified range, test each transmission control wiring harness extension harness AC circuits for an open. If the circuits test normal replace the M15B drive motor with generator assembly.
4. Test for 20-23 ohms between the signal terminal 20 and the signal terminal 21. If less than the specified range, test the transmission control wiring harness extension harness circuits for a short between the signal circuits. If the circuits test normal replace the M15B drive motor with generator assembly. If greater than the specified range, test each transmission control wiring harness extension harness signal circuits for an open. If the circuits test normal replace the M15B drive motor with generator assembly.
5. Test for 23-26 ohms between the signal terminal 17 and the signal terminal 18. If less than the specified range, test the transmission control wiring harness extension harness circuits for a short between the signal circuits. If the circuits test normal replace the M15B drive motor with generator assembly. If greater than the specified range, test each transmission control wiring harness extension harness signal circuits for an open. If the circuits test normal replace the M15B drive motor with generator assembly.
6. Test for greater than 7 ohms between the terminals listed below and ground: Terminal 15 Terminal 16 Terminal 17 Terminal 18 Terminal 20 Terminal 21 If less that the specified value, test the transmission control wiring harness extension harness circuit for a short to ground. If the circuit tests normal replace the M15B drive motor with generator assembly.
7. Test for infinite resistance between the terminals listed below: Terminals 15 and 17 Terminals 15 and 20 Terminals 17 and 20 If less that the specified value, test the transmission control wiring harness extension harness circuits for a short between the circuits. If the circuits test normal replace the M15B drive motor with generator assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
2. «Transmission Control Wiring Harness Extension Harness Removal»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module Assembly replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module monitors its ability to read and write to the memory. The hybrid powertrain control module processor monitors the data to verify that the indicated engine torque delivered calculation is correct.

1. The ignition is ON.
2. The system voltage is 8-18 V.

The control module has detected an internal malfunction.

1. DTC P15F0 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P15F0 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module monitors its ability to read and write to the memory. The hybrid powertrain control module processor monitors the data to verify that the indicated axle torque requested calculation is correct.

1. The ignition is ON.
2. The system voltage is 8-18 V.

The control module has detected an internal malfunction.

1. DTC P15F1 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P15F1 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module sends an engine torque requested message to the ECM over the serial data circuits. The ECM monitors the data to verify the indicated engine torque requested calculation is correct. The ECM processor monitors the data to verify that the engine torque command is correct.

1. The ignition is ON.
2. The system voltage is 8-18 V.
3. DTC U1817 is not set.

The control module has detected an internal malfunction.

1. DTC P15F2 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P15F2 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Note. Diagnose and repair any communication DTCs prior to performing this testing.

If the DTC is set, program the K20 ECM. If the DTC resets, replace the K20 ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hybrid powertrain control module compares the internal mode switch requested direction to other data to verify that the indicated direction range switch calculation is correct.

1. The ignition is ON.
2. Ignition voltage is at least 9.5 V and no more than 18 V.

Condition 1

1. No internal mode switch direction switch DTCs are set.
2. A valid internal mode switch direction indicated by the internal mode switch does not match the direction indicated by the hybrid powertrain control module software.

Condition 2

1. No internal mode switch direction switch DTCs are set.
2. Two valid internal mode switch directions are indicated at the same time.

Condition 3

1. One internal mode switch direction switch circuit has failed.
2. The hybrid powertrain control module calculates a transmission direction based upon the remaining internal mode switch circuits but it does not match the direction indicated by the hybrid powertrain control module software.

Condition 4

1. Multiple internal mode switch directions and one internal mode switch direction switch circuit has failed.
2. Based upon the remaining internal mode switch circuits the hybrid powertrain control module calculated two directions at the same time.

Condition 5

1. More than one internal mode switch direction circuit has failed and the hybrid powertrain control module cannot calculate a transmission direction.
2. Ignition voltage is 9.5-18 V.

1. DTC P16F2 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P16F2 is a Type A DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A or P184B is not set. If any of the DTCs are set, refer to «DTC P181C-P181F, P183A-P183E, P184A, or P184B»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Verify that DTC P16F2 is not set. If the DTC is set, program the hybrid powertrain control module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Drive Motor Generator Power Inverter Module Replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module monitors its ability to read and write to the memory. The hybrid powertrain control module processor stores identical data in two locations and compares the data to verify that the stored data is correct.

The system voltage is 8-18 V.

The control module has detected that identical stored data is not the same when retrieved.

1. DTC P16F3 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P16F3 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTC P1AC6, P0335, or any communication U-code DTC is not set. If DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The internal mode switch assembly is a sliding contact switch located within the transmission. The internal mode switch is integrated into the Manual Shift Shaft Position Switch and is not serviced separately. The nine outputs from the switch indicate which position is selected by the transmission manual shaft. Four outputs (A, B, C, P), are range selection inputs to the transmission control module (TCM). Five outputs (R1, R2, D1, D2, S) are direction selection inputs to the hybrid powertrain control module. The input voltage at the module is high when the switch is open and low when the switch is closed to ground.

The hybrid powertrain control module compares the internal mode switch requested direction to other data to verify that the indicated direction range switch calculation is correct.

1. The ignition is ON.
2. Ignition voltage is at least 8 V and no more than 18 V.

Condition 1

The transmission direction, indicated by both the internal mode range and direction switch circuits, are valid but do not match.

Condition 2

1. One internal mode range direction switch circuit has failed.
2. The hybrid powertrain control module calculates a transmission direction base upon the remaining internal mode range direction circuits.
3. The calculated hybrid powertrain control module transmission direction does not match the direction indicated by the internal mode range switch circuits.

Condition 3

1. One internal mode range direction switch circuit has failed.
2. The hybrid powertrain control module calculates a transmission direction based upon the remaining internal mode range direction circuits.
3. The internal mode range switch indicated a transitional position.

Condition 4

1. One internal mode range direction switch circuit has failed.
2. The hybrid powertrain control module calculates a transmission direction based upon the remaining internal mode range direction circuits.
3. The TCM has indicated at least one internal mode range switch circuit has failed.

Condition 5

1. More than one internal mode range direction circuit has failed and the hybrid powertrain control module cannot calculate a transmission direction.
2. The internal mode range switch indicates a transitional position.

Condition 6

1. More than one internal mode range direction circuit has failed and the hybrid powertrain control module cannot calculate a transmission direction.
2. The TCM has indicated at least one internal mode range switch circuit has failed.

1. DTC P16F4 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P16F4 is a Type A DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A, or P184B is not set. If any of the DTCs are set, refer to «DTC P181C-P181F, P183A-P183E, P184A, or P184B»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Verify that DTC P1824, P182A, P182B, P182C, P182D, P182E, P182F, P1838, or P1839 is not set. If any of the DTCs are set, refer to «DTC P1824, P182A-P182F, P1838, or P1839»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-diagnostic-information-and-procedures) .
3. Verify that DTC P16F4 is not set. If the DTC is set, program the hybrid powertrain control module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module and each motor control module utilize a programmable logic device to perform certain input and output functions. The hybrid powertrain control module monitors the ability of the programmable logic device to perform these functions.

1. The ignition is ON.
2. The system voltage is 8-18 V.

The control module has detected an internal programmable logic device malfunction.

1. DTC P16F5 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P16F5 is a Type A DTC.

An intermittent loss of battery power to the drive motor generator power inverter module may set this DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module monitors its ability to read and write to the memory. The hybrid powertrain control module processor monitors the data to verify that the commanded range state calculation is correct.

1. The ignition is ON.
2. The system voltage is 8-18 V.

The control module has detected the commanded transmission range state is not correct based upon internal calculations or by a comparison to input or output torque conditions.

1. DTC P16F6 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P16F6 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module is internal to the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module and each motor control module utilize a programmable logic device to perform certain input and output functions. The hybrid powertrain control module monitors the ability of the programmable logic device to perform these functions.

1. The ignition is ON.
2. Ignition voltage is 8-18 V.

The control module has detected the internal programmable logic device has not turned on or off correctly.

1. DTC P16F9 is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P16F9 is a Type A DTC.

A low 12 V battery condition, an intermittent loss of power, or loss of communication to the drive motor generator power inverter module may set this DTC.

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTC P0562 is not set. If DTC is set, refer to «DTC P0562»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The internal mode switch assembly is a sliding contact switch attached to the control valve body within the transmission. The internal mode switch is integrated into the Manual Shift Shaft Position Switch and is not serviced separately. The nine outputs from the switch indicate which position is selected by the transmission manual shaft. Four outputs (A, B, C, P), are range selection inputs to the transmission control module (TCM). Five outputs (R1, R2, D1, D2, S) are direction selection inputs to the hybrid powertrain control module. The input voltage at the module is high when the switch is open and low when the switch is closed to ground.

1. The ignition is ON.
2. Ignition voltage is greater than 6.0 V.

The internal mode switch state does not match the selected gear for 3 seconds.

DTCs P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A and P184B are Type B DTCs.

DTCs P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A and P184B are Type B DTCs.

1. The internal mode switch assembly can be damaged by electric current exceeding 25 mA. Test the internal mode switch assembly for an open condition whenever a short to voltage condition is observed.
2. The internal mode switch is a non-serviceable part of the manual shift shaft position switch.
3. The internal mode switch parameter displaying HI for each range indicates an open ground circuit or connector for the internal mode switch.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. DT-47825-10 Jumper Harness
2. DT-48493 Jumper Harness

For equivalent regional tools, refer to Special Tools .

Ignition ON, observe the scan tool internal mode switch parameters while moving the gear shift lever from Park, through all gear selector positions, and back to Park. The parameters should match each gear range that is selected. Refer to Internal Mode Switch table below

Internal Mode Switch Parameters

1. Ignition OFF. Disconnect the X176 24-way harness connector at the transmission. Additional DTCs may set.
2. Install the DT-48493 jumper harness to the harness side only.
3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 10 ohms between the low reference circuit terminal 5 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
4. Ignition ON, verify each scan tool D1/D2/R1/R2 parameter displays high. If any parameter displays low, test the signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the T6 drive motor generator power inverter module. Parameter D1 - terminal 3 Parameter D2 - terminal 4 Parameter R1 - terminal 1 Parameter R2 - terminal 2
5. Install a 3 A fused jumper wire between each terminal listed below one at a time and ground. Verify each scan tool D1/D2/R1/R2 parameter displays low when grounded. If a parameter displays high when grounded, test the signal circuit terminal listed below for a short to voltage or an open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter module. Parameter D1 - terminal 3 Parameter D2 - terminal 4 Parameter R1 - terminal 1 Parameter R2 - terminal 2
6. Ignition OFF, disconnect the X1 16-way harness connector at the transmission.
7. Install the DT-47825-10 jumper harness to the harness side only.
8. Ignition ON, verify the scan tool S parameter displays high. If the S parameter displays low, test the signal circuit terminal 3 X1 for a short to ground. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
9. Install a 3 A fused jumper wire between the signal terminal 3 X1 and ground. Verify the scan tool S parameter is low. If the S parameter displays high, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
10. If the circuits test normal, test or replace the transmission internal extension harness or the automatic transmission B15 internal mode switch.

1. Ignition OFF. Disconnect the X176 24-way harness connector at the transmission.
2. Install the DT-48493 jumper harness to the transmission side only.
3. Disconnect the X1 16-way harness connector at the transmission.
4. Install the DT-47825-10 jumper harness to the transmission side only.
5. Transmission in PARK, test for less than 10 ohms between the low reference circuit terminal 5 at the transmission and each signal circuit terminal listed below at the transmission: Terminal D2 X176 Terminal R2 X176 Terminal S X16 If not within the specified range, test the transmission internal extension harness signal circuit for an open/high resistance, if the circuit tests normal replace the automatic transmission internal B15 mode switch.
6. Test for infinite resistance between the low reference circuit terminal 5 at the transmission and each signal circuit terminal listed below at the transmission: Terminal D1 X176 Terminal R1 X176 If not the specified value, test the transmission internal extension harness signal circuit for a short to ground, if the circuit tests normal replace the automatic transmission B15 internal mode switch.
7. Parking brake applied with the transmission in NEUTRAL, test for less than 10 ohms between the low reference circuit terminal 5 at the transmission and each signal circuit terminal listed below at the transmission: Terminal D1 X176 Terminal R1 X176 If not within the specified range, test the transmission internal extension harness signal circuit for an open/high resistance, if the circuit tests normal replace the automatic transmission B15 internal mode switch.
8. Test for infinite resistance between the low reference circuit terminal 5 at the transmission and each signal circuit terminals listed below at the transmission: Terminal D2 X176 Terminal R2 X176 If not the specified value, test the transmission internal extension harness signal circuit for a short to ground, if the circuit tests normal replace the automatic transmission B15 internal mode switch.
9. Transmission in REVERSE, test for infinite resistance between the low reference circuit terminal 5 at the transmission and the signal circuit terminal 3 X1 at the transmission. If not the specified value, test the transmission internal extension harness signal circuit for an open/high resistance, if the circuit tests normal replace the automatic transmission B15 internal mode switch.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Manual Shift Shaft Position Switch Replacement»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle)
2. «Transmission Control Wiring Harness Extension Harness Removal»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hybrid powertrain control module compares the internal mode switch requested direction to other data to verify that the indicated direction range switch calculation is correct.

1. The ignition is ON
2. DTCs P181C-P181F, P1824, P182A-P182F, P183A-P183E, P1838, P1839, P184A, or P184B are not set.

The internal mode switch direction state does not match the internal mode switch range state.

DTC P183F is a Type A DTC.

DTC P183F is a Type A DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC P181C, P181D, P181E, P181F, P183A, P183B, P183C, P183D, P183E, P184A or P184B is not set. If any of the DTCs are set, refer to «DTC P181C-P181F, P183A-P183E, P184A, or P184B»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Verify that DTC P183F is not set. If the DTC is set, program the hybrid powertrain control module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor control modules are internal to the drive motor generator power inverter module assembly and are not serviced separately. This fault is handled inside the drive motor control modules and no external circuits are involved.

1. The ignition is ON.
2. Ignition voltage is 8-18 V.

The control module has detected an internal malfunction.

1. DTCs P1A4F, P1A50, P1A51, P1A52, P1A53, P1A54, P1ADC and P1ADD are Type A DTCs.
2. The drive motor generator power inverter module commands the battery energy control module to open the high voltage contactor relays.

DTCs P1A4F, P1A50, P1A51, P1A52, P1A53, P1A54, P1ADC and P1ADD are Type A DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power control module supplies the energy that flows between the high voltage, 300 volt, DC and intermediate voltage, 42 volt, DC to support the electric power steering. The accessory DC power control module receives a 42 volt enable command from the hybrid powertrain control module over serial data. 42 volt accessory DC power module functions will run only when the 42 volt accessory DC power control module enable is active through serial data.

The accessory DC power control module continuously monitors the status of its 42 volt circuitry. When the ignition key is first turned to RUN, some diagnostics are performed on this circuitry. When the engine is started, and the 42 V enable command is received by the accessory DC power control module, additional diagnostics are run.

1. Ignition voltage is 7 V and no more than 16 V.
2. The accessory DC power control module runs a portion of the diagnostics for this DTC at Accessory/Ignition On.
3. The accessory DC power control module runs additional diagnostics when the 42 volt output is commanded on.

1. An external condition has caused an accessory DC power control module 42 volt malfunction, OR
2. The accessory DC power control module has detected an internal malfunction.

1. DTC P1A88 is a Type C DTC.
2. The accessory DC power control module will shutdown 42 volt conversion.

DTC P1A88 is a Type C DTC.

This DTC can set as a result of conditions external to the accessory power control module. Before attempting to diagnose a history DTC, ensure that none of the following conditions have occurred

1. High voltage contactor relays opening any time the accessory DC power control module is doing 42 volt conversion.
2. The high voltage system greater than 390 volts or less than 216 volts during 42 volt conversion. Extreme cold weather conditions may occasionally cause the high voltage system to be greater than 390 volts.
3. The 12 volt circuit was less than 6.7 volts during 42 volt conversion.
4. A short circuit condition on the 42 volt circuit which causes the accessory DC power control module to produce greater than 60 amps.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify there is no other hybrid DTCs set. If other Hybrid DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Ignition ON, engine OFF, observe the scan tool battery energy control module contactor system status parameter. The status should display closed. If not the specified value, refer «Symptoms - Hybrid Controls»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__symptoms-hybrid-controls) .
3. Verify that DTC P1A88 is not set as current. If the DTC is set as current, replace the K1 accessory DC power control module.
4. Ignition OFF, disconnect the X2 harness connector at the K1 accessory DC power control module.
5. Ignition ON, engine OFF, command the accessory DC power control module Intermediate Voltage Control ON with a scan tool. Test for 42V between the K1 accessory DC power control module X2 terminal 1 and 2. The reading should be between 40 V and 44 V. If not within the specified range, replace the K1 accessory DC power control module.
6. Ignition OFF, connect the X2 harness connector at the K1 accessory DC power control module.
7. Ignition ON, engine OFF, command the accessory DC power module Intermediate Voltage Control ON with a scan tool. Verify the 42V circuit parameter between 40 V and 44 V. If not within the specified range, replace the M38 power steering assist motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Power Steering Assist Motor Replacement»(/gmc/sierra-2500/2012-2012/remont/manual-power-steering/#power-steering-system)
2. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Power Steering Motor Control Module or Accessory DC Power Control Module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power control module supplies the energy that flows between the high voltage, 300 volt, DC and intermediate voltage, 42 volt, DC to support the electric power steering. The accessory DC power control module receives a 42 volt enable command from the hybrid powertrain control module over serial data. 42 volt accessory DC power module functions will run only when the 42 volt accessory DC power control module enable is active through serial data.

Accessory DC power control module 42 volt output commanded on.

42 volt circuit below 21 volts during operation.

1. DTC P1A89 is a Type C DTC.
2. The accessory DC power control module will shutdown 42 volt conversions.

DTC P1A89 is a Type C DTC.

The 42 volt circuit is only used by the electronic power steering. The accessory DC power control module can apply 42 volts on the connector without being connected to the electronic power steering.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Engine running, verify the scan tool 42V Circuit Voltage parameter on the accessory DC power control module data list is greater than 40V. If less than the specified value refer to Circuit/System Testing below.
2. Verify the scan tool 42V Circuit Voltage parameter is greater than 40V, while rotating the steering wheel back and forth while the vehicle is stationary. If less than the specified value, replace the M38 power steering assist motor.

1. Ignition OFF, disconnect the X2 harness connector at the K1 accessory DC power control module.
2. Ignition ON, command the accessory DC power control module Intermediate Voltage Control on the scan tool to turn On the 42 volt circuit.
3. Test for 40-44 V between the 42 V reference output terminals 1 and 2 at the K1 accessory DC power control module. If less than the specified range, replace the K1 accessory DC power control module.
4. If the accessory DC power control module 42 V output tests normal, replace the K43 power steering control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Power Steering Assist Motor Replacement»(/gmc/sierra-2500/2012-2012/remont/manual-power-steering/#power-steering-system)
2. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Accessory DC Power Control Module and the Power Steering Control Module replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power control module supplies the energy that flows between the high voltage, 300 volt, direct current (DC) and intermediate voltage, 42 volt, DC to support the electric power steering. The accessory DC power control module receives a 42 volt enable command from the hybrid powertrain control module over serial data. 42 volt accessory DC power control module functions will run only when the 42 volt accessory DC power control module enable is active on serial data.

Accessory DC power control module 42 volt output commanded on.

Accessory DC power control module 42 volt circuit is more than 50 V for more than 3 seconds.

1. DTC P1A8A is a Type C DTC.
2. The Accessory DC power control module will shutdown the 42 volt conversion.

1. DTC P1A8A is a Type C DTC.
2. 42 volt circuit is below 48 V.

The accessory DC power control module Data List on the scan tool contains the parameter 42V Circuit Maximum. If this parameter has a voltage that is greater than 50 V, and the accessory DC power control module is functioning normally, the protection circuits in the power steering control module have failed allowing induced voltage to be present on the 42 V circuit.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Engine running, observe the 42V Circuit Voltage parameter on the accessory DC power control module data list.

1. If the 42V Circuit Voltage parameter is greater than 48 volts, replace the K1 accessory DC power control module.
2. If the 42V Circuit Voltage parameter is less than 48 volts, replace the K43 power steering control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Accessory DC Power Control Module or Power Steering Control Module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power control module supplies the energy that flows between the high voltage, 300 volt, direct current (DC) and intermediate voltage, 42 volt, DC to support the electric power steering. The accessory DC power control module receives a 42 volt enable command from the hybrid powertrain control module over serial data. 42 volt accessory DC power control module functions will run only when the 42 volt accessory DC power control module enable is active on serial data.

Heat is generated in the 42 volt accessory DC power control module primarily through the demand for use of the electronic power steering. The ECM measures the temperature of the power electronics cooling loop and commands the flow of 2 electrical coolant pumps. The accessory DC power control module transfers heat from the 42 volt circuit to the accessory DC power control module heat plate which is then dissipated at the Generator Control Module Coolant Radiator.

Based on the severity of the over temperature condition in the 42 volt circuit, the accessory DC power control module will take actions ranging from notifying the electronic power steering control module of an over temperature condition to completely shutting down 42 volt power conversion.

Accessory DC power control module 42 volt output commanded on.

P1A8B 00

42 volt circuit temperature is greater than 105°C (221°F).

P1A8B 11

42 volt circuit temperature is greater than 115°C (239°F).

P1A8C

42 volt circuit temperature is greater than 125°C (257°F).

P1A8B

1. DTC P1A8B is a Type C DTC.
2. The hybrid powertrain control module stores the DTC information in memory when the diagnostic runs and fails.

P1A8C

1. DTC P1A8C is a Type C DTCs.
2. The hybrid powertrain control module stores the DTC information in memory when the diagnostic runs and fails.
3. The accessory DC power control module will shut down 42-volt conversion.

P18AB

DTC P1A8B is a Type C DTC.

P1A8B 00

DTC P1A8B 00 is a Type C DTC.

P1A8B 11

DTC P1A8B 11 is a Type C DTC.

P1A8C

DTC P1A8C is a Type C DTC.

This DTC could be caused by a possible power electronics cooling system failure due to the following

1. Restricted radiator air flow or coolant fans inoperative
2. Restricted power electronics coolant flow or contaminated coolant
3. Inoperative power electronics cooling system water pump

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC P0AF7 is not set. If the DTC is set, refer to «DTC P0AF7»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Engine running, place the steering wheel in the centered position. Do not rotate the steering wheel. Verify the accessory DC power control module scan tool 42V Circuit Current parameter is less than 0.5 A. If greater than the specified value, replace the K43 power steering control module.
3. Observe the 42V Circuit Current parameter while rapidly rotating the steering wheel to the full left stop then to the full right stop. The highest current reading should be below 40 A. If the current is greater than the specified value, replace the K43 power steering control module. If the reading is less than the specified value, replace the K1 accessory DC power control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Accessory DC Power Control Module or Power Steering Control Module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The crankshaft position sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The crank shaft position sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The crankshaft position sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the crankshaft position sensor output depends on the velocity of the crankshaft. The crankshaft position sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the crankshaft position sensor. The ECM uses each crankshaft position signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The ECM also uses crankshaft position sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire, and to control the camshaft position actuator if equipped.

Motor control module 1 is also connected to the crankshaft position sensor signal and low reference circuits. The motor control module uses the crankshaft position sensor output information to determine engine crankshaft position to aid in smooth engine Auto-starts. The motor control module does not need the crankshaft position sensor signal in order for the engine to start and run.

P1AC6 and P1AC7

1. Drive motor generator 1 is rotating.
2. The DTC runs continuously when the above conditions are met.

P1AC6

The motor control module detects no engine speed signal for 2 seconds.

P1AC7

The motor control module detects an invalid engine speed signal for 3 seconds.

DTCs P1AC6 and P1AC7 are Type B DTCs.

DTCs P1AC6 and P1AC7 are Type B DTCs.

With an ECM DTC P0335 set, the engine will only crank for about 2 seconds.

Schematic Reference

1. «Hybrid Controls Schematics»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
2. «Engine Controls Schematics»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-wiring-schematic-diagrams)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTCs P0335 or P0336 is not set. If DTCs P0335 or P0336 is set, refer to «DTC P0335»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-dt-p0010-to-dtc-p0341) , or «DTC P0336»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-dt-p0010-to-dtc-p0341) .
2. Engine running, observe the hybrid powertrain control module Engine Speed parameter with a scan tool. The parameter should display the current engine speed, matching the tachometer and/or the ECM Engine Speed parameter. If the hybrid powertrain control module Engine Speed parameter displays a value other than the current engine speed, continue with Circuit/System Testing.

1. Ignition OFF, remove the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Disconnect the T6 drive motor generator power inverter module connector X1 and the crankshaft position sensor connector.
3. Test for less than 5 ohms on the crankshaft position low reference circuit, from connector X1 terminal 35 and ground. If greater than the specified value, repair the low reference circuit for an open/high resistance.
4. Ignition ON, test for 4.8-5.2 V on the crankshaft position signal circuit, from the connector X1 terminal 26 and ground. If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Control Module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two motor control modules and a hybrid powertrain control module. The hybrid powertrain control module and both motor control modules share the drive motor generator power inverter module ignition voltage circuit, battery voltage circuits and chassis ground.

The ignition is ON.

Motor control module ignition voltage is less than 7.7 V for 1 second.

DTCs P1ADE and P1AE0 are Type C DTCs.

DTCs P1ADE and P1AE0 are Type C DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTC P0562 is not set. If DTC P0562 is set, refer to «DTC P0562»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

HVIC Source Current - Battery Energy Control Module

HVIC Return Current - Battery Energy Control Module

Hybrid Powertrain Control Module HVIC Status - Hybrid Powertrain Control Module

Battery Energy Control Module HVIC Status - Hybrid Powertrain Control Module

The high voltage interlock circuit is utilized to verify high voltage component integrity. High voltage interlock circuit is a circuit loop that passes through certain high voltage components. High voltage interlock circuit is used to determine if access to high voltage components is being attempted. The opening of these high voltage components causes the high voltage interlock circuit to open. The battery energy control module sources about 12 mA of current on the 5V high voltage interlock circuit loop. The battery energy control module monitors both the high voltage interlock source current circuit and the high voltage interlock return current circuit in order to detect circuit faults. Both motor control modules monitor the circuit for current in order to detect an open condition. When the battery energy control module and/or the motor control modules sense conditions such as a loss of high voltage interlock circuit current, the high voltage contactor relays are commanded open by the hybrid powertrain control module.

P1B05 and P1B06

1. The ignition voltage is 8-18 V.
2. Wake up signal is active.
3. Battery energy control module is supplying current on the high voltage interlock circuit. This normally occurs when high voltage contactor relays are closed.

P1AE2, P1AE3 and P1AE4

1. The ignition voltage is 9-18 V.
2. Wake up signal is active.
3. Battery energy control module is supplying current on the high voltage interlock circuit. This normally occurs when high voltage contactor relays are closed.

P1B05 and P1B06

1. The motor control module does not detect high voltage interlock circuit current flow.
2. DTC P1B05 and P1B06 set within 1 second when the above condition is met.

P1AE2

1. The battery energy control module detects high voltage interlock circuit source current is less than 5 mA and high voltage interlock return current is less than 5 mA.
2. DTC P1AE2 sets within 1 second when the above condition is met.

P1AE3

1. The battery energy control module detects high voltage interlock source current is between 5-18 mA and high voltage interlock return current is less than 5 mA.
2. DTC P1AE3 sets within 1 second when the above condition is met.

P1AE4

1. The battery energy control module detects high voltage interlock source current is less than 5 mA and high voltage interlock return current is greater than 35 mA.
2. DTC P1AE4 sets within 1 second when the above condition is met.

1. DTCs P1B05, P1B06, P1AE2, P1AE3, P1AE4 are Type C DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays when vehicle speed is less than 5 km/h (3 mph) for 6 seconds.

DTCs P1B05, P1B06, P1AE2, P1AE3, P1AE4 are Type C DTCs.

1. Test for a fully engaged high voltage manual disconnect lever whenever an open high voltage interlock circuit condition is observed. The manual disconnect lever must be pressed down fully in order to engage the high voltage interlock circuit terminals.
2. The battery energy control module high voltage interlock source circuit and high voltage interlock return circuit current sensors may not measure actual circuit current with the same accuracy. The battery energy control module high voltage interlock source circuit parameter may indicate less current than the battery energy control module high voltage interlock return circuit parameter for this reason. Measuring actual HVIC current with a DMM may also not compare directly to the parameter display.
3. The high voltage interlock circuit detects removal of the following components: The drive motor generator control module sight shield The transmission 3 phase cable cover The high voltage manual disconnect lever The hybrid battery terminal extension cover assembly
4. The high voltage interlock circuit is also routed through several inline connectors.
5. With the ignition in the OFF position, the battery energy control module will source the high voltage interlock circuit current for 5 minutes every time a vehicle door is opened.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Note. The hybrid powertrain control module must command the high voltage contactor relays closed in order for high voltage interlock circuit to be enabled. Fail will be displayed if any DTCs present at ignition ON prevent the hybrid powertrain control module from closing the high voltage contactor relays.

If the DTC set, Record and then clear the DTC information. Ignition OFF, wait 2 minutes. Ignition ON, observe the scan tool HPCMs battery energy control module HVIC Status and hybrid powertrain control module HVIC Status parameters. The parameters should both indicate a PASS condition.

P1B05 and P1B06 without P1AE2, P1AE3 or P1AE4

1. Ignition OFF, remove the F103 drive motor generator power inverter module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) , and disconnect the X1 harness connector at the T6 drive motor generator power inverter module.
2. Ignition OFF, wait 2 minutes. Install the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ignition ON, observe the scan tool battery energy control module HVIC Source Current parameter should read less than 5 mA. If greater than specified value, test for the HVIC Source and HVIC Return circuits shorted together between X1 harness connector at the T6 drive motor generator power inverter module and X350 harness connector of A4 hybrid battery pack assembly.
3. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure and test for the HVIC Source and HVIC Return circuits shorted together between X350 harness connector at the A4 hybrid battery pack assembly and X1 harness connector at the K16 battery energy control module. If the circuit tests normal, replace the K16 battery energy control module.
4. If the circuit tests normal, test for open circuit between the hybrid voltage interlock circuit return circuit terminal 1 and the hybrid voltage interlock circuit source circuit terminal 23. If the circuit tests normal, replace the T6 drive motor generator power inverter module.

P1B05 and P1B06 with P1AE2

1. Ignition OFF, remove the F103 drive motor generator power inverter module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) , and disconnect the X1 harness connector at the T6 drive motor generator power inverter module.
2. Install a 3 A fused jumper wire between the hybrid voltage interlock circuit return circuit terminal 1 and the hybrid voltage interlock circuit source circuit terminal 23.
3. Ignition OFF, wait 2 minutes. Install the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ignition ON, observe the scan tool HVIC Source Current parameter, the reading should be between 5-18 mA. If less than the specified range, Remove the 3 A fused jumper wire.
4. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure and test hybrid voltage interlock source circuit and hybrid voltage interlock return circuit for an open/high resistance. If circuits test normal, replace the K16 battery energy control module.
5. If the circuit tests normal, Test for open circuit between the hybrid voltage interlock circuit return circuit terminal 1 and the hybrid voltage interlock circuit source circuit terminal 23. If the circuit tests normal, replace the T6 drive motor generator power inverter module.

P1AE3 with or without P1B05 and P1B06

1. Ignition OFF, remove the F103 drive motor generator power inverter module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) , and disconnect the X1 harness connector at the T6 drive motor generator power inverter module.
2. Ignition OFF, wait 2 minutes. Install the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ignition ON, observe the scan tool battery energy control module HVIC Source Current parameter should read less than 5 mA. If the HVIC Source Current parameter indicates current between 5-18 mA test the HVIC Source circuit for a short to ground between X1 harness connector at the T6 drive motor generator power inverter module and X350 harness connector at the A4 hybrid battery pack assembly.
3. Install a 3A fused jumper wire between the HVIC return circuit terminal 1 and the HVIC Source circuit terminal 23.
4. Ignition ON, observe the scan tool battery energy control module HVIC Source Current and HVIC Return Current parameters should be between 5-18 mA. If both circuits test normal, replace the T6 drive motor generator power inverter module. If only the HVIC Source Current parameter indicates current between 5-18 mA test the hybrid voltage interlock return circuit for a short to ground between X1 harness connector at the T6 drive motor generator power inverter module and X350 harness connector at the A4 hybrid battery pack assembly.
5. Remove 3A jumper fuse and test the high voltage interlock return circuit for a short to ground between X350 harness connector at the A4 hybrid battery pack assembly, and X1 harness connector at the K16 battery energy control module. If the circuit tests normal, replace the K16 battery energy control module.

P1AE4 with or without P1B05 and P1B06

1. Ignition OFF, remove the F103 drive motor generator power inverter module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) , and disconnect the X1 harness connector at the T6 drive motor generator power inverter module.
2. Ignition OFF, wait 2 minutes. Install the F103 drive motor generator control module sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) . Ignition ON, test for less than 35 mA between the hybrid voltage interlock source circuit terminal 23 and ground. If more than the specified range, test the hybrid voltage interlock source circuit for a short to voltage between X1 harness connector at the T6 drive motor generator power inverter module and X350 harness connector at the A4 hybrid battery pack assembly.
3. Ignition ON, test for less than 35 mA with a DMM between the hybrid voltage interlock return circuit terminal 1 and ground. NOTE: Removal of the high voltage manual disconnect lever also opens the HVIC source circuit between X350 and battery energy control module connector X1. If more than the specified range, test the hybrid voltage interlock return circuit for a short to voltage between X1 harness connector at the T6 drive motor generator power inverter module and X350 harness connector at the A4 hybrid battery pack assembly.
4. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure and test the HVIC Return circuit for a short to voltage between X350 harness connector at the A4 hybrid battery pack assembly and X1 harness connector at the K16 battery energy control module. If the circuit tests normal, replace the K16 battery energy control module.
5. Replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module or Battery Energy Control Module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter module contains two drive motor control modules. Each drive motor control module monitors its internal high voltage sensor for correct operation, no external circuits are involved. The modules listed below are part of the drive motor generator power inverter module and are not serviced separately.

1. Hybrid powertrain control module
2. Motor control module 1
3. Motor control module 2

1. Ignition is ON.
2. The system voltage is 8-18 V.
3. The high voltage contactor relays are closed.

P1AE8 and P1AEA

The drive motor control module detects high voltage sensor voltage less than 0V.

P1AE9 and P1AEB

The drive motor control module detects high voltage sensor voltage greater than 564V. Cert Doc = 500 V.

1. DTCs P1AE8, P1AE9, P1AEA and P1AEB are Type B DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P1AE8, P1AE9, P1AEA and P1AEB are Type B DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The power inverter module, also called the drive motor generator power inverter module, contains two motor control modules. Each motor control modules measures hybrid battery high voltage with several internal sensors. The hybrid powertrain control module 2 also monitors high voltage with several internal sensors. The hybrid powertrain control module 2 high voltage measurement is broadcast over serial data.

P1AEC and P1AED

The motor control modules compare the values in order to verify the hybrid battery high voltage measurement is accurate.

P1AEE and P1AEF

The motor control modules monitors for high voltage that is greater than the system allows during normal operation.

1. The hybrid/EV battery system contactor relays are closed.
2. Ignition voltage is 8 V and no more than 18 V.

P1AEC

DTCs P1AE8 or P1AE9 are not set.

P1AED

DTCs P1AEA or P1AEB are not set.

P1AEC and P1AED

A difference of more than 40 V on the high voltage circuit is detected between the hybrid powertrain control module and the hybrid powertrain control module 2.

AND

A difference of more than 50 V on the high voltage circuit is detected between the motor control module and the hybrid powertrain control module 2.

P1AEE and P1AEF

Greater than 425 V on the high voltage circuit is detected by the motor control module.

1. DTCs P1AEC and P1AED are Type B DTCs.
2. DTCs P1AEE and P1AEF are Type A DTCs.
3. The power inverter module requests the hybrid powertrain control module 2 to open the high voltage contactor relays.

1. DTCs P1AEC and P1AED are Type B DTCs.
2. DTCs P1AEE and P1AEF are Type A DTCs.

Conditions such as loss of battery energy control module power or ground or removal of the high voltage manual disconnect while the vehicle was driving could create a voltage surge that may set DTCs P1AEE and P1AEF. History DTCs P1AEE and P1AEF may indicate that the high voltage contactor relays opened while large current flow was present.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTCs P0ABB, P0ABC, or P0ABD is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. If the DTC is set, program the hybrid powertrain control module. If the DTC resets, replace the T6 power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter module, also called the power inverter module, replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module contains two motor control modules. Each motor control module measures hybrid battery high voltage with several internal sensors. The motor control modules test for loss of isolation between either the high voltage positive circuit or high voltage negative circuit and vehicle chassis. The motor control modules test for isolation when the high voltage contactor relays are closed. The battery energy control module only tests the hybrid battery assembly for high voltage loss of isolation when the high voltage contactor relays are open.

Motor control modules loss of isolation is detected through the use of two high-impedance resistors and voltage measuring circuitry. The two resistors are connected in series between the high voltage positive and high voltage negative circuits. The center connection of the two resistors is also connected to vehicle chassis. The motor control module then measures the voltage drop across one of the resistors. Without a loss of isolation, the motor control module should measure about half of the high voltage potential. This is referred to as mid-pack voltage. The Mid-pack voltage value is then doubled by the software and displayed on a scan tool as Motor 1 Isolation Voltage or Motor 2 Isolation Voltage. When a loss of isolation is present, the motor isolation voltage display will indicate voltage that is more or less than actual hybrid battery high voltage.

1. The high voltage contactor relays are closed.
2. High voltage is greater than 50 V.
3. Ignition voltage is 8-18 V.
4. DTCs P1AEE, P1AF4, and P1AF5 are not set.

The ratio between Mid-Pack Voltage and hybrid battery high voltage is less than 0.27 or greater than 1.80.

OR

1. Mid-Pack Voltage is less than 35 V or greater than 975 V.
2. Either above condition exists for 5 seconds.

DTCs P1AF0 and P1AF2 are Type C DTCs.

DTCs P1AF0 and P1AF2 are Type C DTCs.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. EL-48458 Pre-Charge Test Tool
2. EL-48569 Terminal Covers

For equivalent regional tools, refer to Special Tools .

1. Verify that DTC P1AE7 is not set. If the DTC is set, refer to «DTC P1AE6 or P1AE7»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system) .
2. Verify that DTCs P0A78, P0A79, P0BFD, P0BFE, P0C01, or P0C04 is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
3. Ignition ON, engine OFF, observe the scan tool battery energy control module contactor system status parameter. The status should display closed. If not the specified value, refer to «Symptoms - Hybrid Controls»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__symptoms-hybrid-controls) .
4. Hood closed, transmission in park, and Ignition OFF for at least 2 minutes.
5. Ignition ON, engine OFF, within 5 seconds of ignition ON, observe the hybrid powertrain control module 300V Circuit parameter and compare it to both data parameters listed below. Each motor parameter should be within 20 V of the hybrid powertrain control module 300 V circuit parameter. Motor 1 Isolation Voltage Motor 2 Isolation Voltage If only one Motor Isolation Voltage value is not within the specified range, replace the drive motor generator power inverter control module. If both Motor Isolation Voltage values are not within the specified range, refer to DC Circuit Testing in Circuit/System Testing below.
6. If both Motor Isolation Voltage values are within the indicated range, a loss of isolation condition is not currently present, refer to AC Circuit Testing in Circuit/System Testing below.

DC Circuit Testing

1. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
2. Remove the air conditioning control module high voltage cable connector from the drive motor generator power inverter module. Protect the terminal ends immediately with the EL-48569 terminal covers and UL® Listed or equivalent insulation tape rated at a minimum of 600 volts.
3. Temporarily install the drive motor generator control module high voltage distribution cover.
4. Install the drive motor generator control module sight shield.
5. Install the high voltage manual disconnect lever.
6. Connect the 12 volt battery. Refer to «Battery Negative Cable Disconnection and Connection»(/gmc/sierra-2500/2012-2012/remont/charging-system/#engine-electrical-battery-hybrid-hp2) .
7. Ignition ON, engine OFF, within 5 seconds of ignition ON, observe the hybrid powertrain control module 300V Circuit parameter and compare it to both data parameters listed below. Both motor parameters should be at least 20 V less than the hybrid powertrain control module 300V circuit parameter. Motor 1 Isolation Voltage Motor 2 Isolation Voltage If both motor parameters pass, replace the air conditioning control module.
8. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
9. Disconnect the 300 V Battery Positive and Negative Cable Assembly connector at the drive motor generator power inverter module.
10. Remove and retain the cable mounting block O-ring. Re-install the O-ring after testing is complete.
11. Disconnect the X1 harness connector at the drive motor generator power inverter module.
12. Connect the EL-48458 test tool at the 300 V Battery Positive and Negative Cable Assembly and the drive motor generator power inverter module X1 harness connector. Refer to «High Voltage System Diagnosis (EL-48458)»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__high-voltage-system-diagnosis-el-48458) for Installation Procedure, set-up, and usage instructions.
13. Using the EL-48458 test tool move the high voltage contactor switch to the CLOSED position. The greater than 60V lamp should be illuminated. If the Greater than 60V When Lit lamp does not illuminate inspect «Drive Motor Generator Battery Control Module Scan Tool Information»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-specifications-scan-tool-information-1-of-2__drive-motor-generator-battery-control-module) for the contactor open reasons such as an open high voltage interlock circuit condition. Repair the reason for the open contactor condition, turn the ignition OFF and repeat this step.
14. Ensure the output control limits are not violated when this output control is initiated. Refer to «Drive Motor Generator Battery Control Module Scan Tool Information»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-specifications-scan-tool-information-1-of-2__drive-motor-generator-battery-control-module) for the control limits.
15. Activate the battery energy control module 300V Isolation Test output control with the scan tool. The Isolation Test should complete within 1 minute. Observe the 300V Isolation Test Status scan tool parameter. The test status should display FAIL when the test is completed. If the 300V Isolation Test displays PASS, replace the drive motor generator power inverter module and the accessory DC power control module.
16. Verify high voltage is not present before disconnecting the EL-48458 test tool from the vehicle. Refer to «High Voltage System Diagnosis (EL-48458)»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__high-voltage-system-diagnosis-el-48458) for Removal Procedure.
17. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator battery.
18. Disconnect the 300V Battery Positive and Negative Cable Assembly connector at the drive motor generator battery assembly. Protect the terminal ends immediately with the EL-48569 terminal covers and UL® Listed or equivalent insulation tape rated at a minimum of 600 volts.
19. Using the extension harness connect the EL-48458 test tool at the hybrid battery 300 V positive and negative terminals.
20. Connect the EL-48458 test tool the drive motor generator power inverter module X1 harness connector. Refer to «High Voltage System Diagnosis (EL-48458)»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__high-voltage-system-diagnosis-el-48458) for Installation Procedure, set-up, and usage instructions.
21. Using the EL-48458 test tool move the high voltage contactor switch to the CLOSED position. The greater than 60V lamp should be illuminated. If the Greater than 60V When Lit lamp does not illuminate inspect «Drive Motor Generator Battery Control Module Scan Tool Information»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-specifications-scan-tool-information-1-of-2__drive-motor-generator-battery-control-module) for the contactor open reasons such as an open high voltage interlock circuit condition. Repair the reason for the open contactor condition, turn the ignition OFF and repeat this step.
22. Verify the output control limits are not violated when this output control is initiated. Refer to «Drive Motor Generator Battery Control Module Scan Tool Information»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-specifications-scan-tool-information-1-of-2__drive-motor-generator-battery-control-module) for the control limits.
23. Activate the battery energy control module 300V Isolation Test output control with the scan tool. The Isolation Test should complete within 1 minute. Observe the 300V Isolation Test Status scan tool parameter. The test status should display FAIL when the test is completed. If the 300V Isolation Test displays PASS, replace the 300 V Battery Positive and Negative Cable Assembly.
24. If the Isolation Test Status displays FAIL the loss of isolation has occurred within the hybrid battery between the switched side of the high voltage contactors and the hybrid battery high voltage terminal assembly. Replace or repair the drive motor generator battery.

AC Circuit Testing

1. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
2. Remove the 3-phase cable assembly from the T6 drive motor generator control module distribution box. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
3. Test for infinite resistance between each of the AC circuit terminals listed below and ground: Drive motor 1st position phase U terminal Drive motor 1st position phase V terminal Drive motor 1st position phase W terminal Drive motor 2nd position phase U terminal Drive motor 2nd position phase V terminal Drive motor 2nd position phase W terminal If not the specified value, test the AC circuit for a short to ground or a short between the AC circuit terminals and the aluminum cable mounting block. If the circuit tests normal replace the appropriate M15 drive motor with generator assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor Battery Positive and Negative Cable Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system)
2. «Air Conditioning Compressor Replacement (LU3)»(/gmc/sierra-2500/2012-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-compressor-replacement-lu3) , «Air Conditioning Compressor Replacement (LZ1, L20, LC9, L9H, L92, LMG)»(/gmc/sierra-2500/2012-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-compressor-replacement-lz1-l20) , «Air Conditioning Compressor Replacement (LGH, LML)»(/gmc/sierra-2500/2012-2012/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
3. «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
4. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
5. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
6. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module and Accessory DC Power Control Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module contains two motor control modules. Each motor control module measures hybrid battery high voltage with several internal sensors. The motor control modules test for loss of isolation between either the high voltage positive circuit or high voltage negative circuit and vehicle chassis. The motor control modules test for isolation when the high voltage contactor relays are closed. The battery energy control module only tests the hybrid battery assembly for high voltage loss of isolation when the high voltage contactor relays are open.

Motor control module loss of isolation is detected through the use of two high-impedance resistors and voltage measuring circuitry. The two resistors are connected in series between the high voltage positive and high voltage negative circuits. The center connection of the two resistors is also connected to vehicle chassis. The motor control module then measures the voltage drop across one of the resistors. Without a loss of isolation, the motor control module should measure about half of the high voltage potential. This is referred to as mid-pack voltage. The Mid-pack voltage value is then doubled by the software and displayed on a scan tool as Motor 1 Isolation Voltage or Motor 2 Isolation Voltage. When a loss of isolation is present, the motor isolation voltage display will indicate voltage that is more or less than actual hybrid battery high voltage. The motor control module monitors the loss of isolation voltage measuring circuitry for correct operation.

1. The motor control module runs the program to detect an internal fault when the key is ON.
2. Ignition voltage is 8-18 V.

P1AF4 and P1AF6

The motor control module detects isolation sensor voltage less than 0V.

P1AF5 and P1AF7

The motor control module detects isolation sensor voltage greater than 564V.

1. DTCs P1AF4, P1AF5, P1AF6 and P1AF7 are Type B DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P1AF4, P1AF5, P1AF6 and P1AF7 are Type B DTCs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTC P1AE7 is not set. If the DTC is set, refer to «DTC P1AE6 or P1AE7»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system) .
2. Verify that DTCs P1AF4, P1AF5, P1AF6 and P1AF7 is not set. If the DTC is set, program the drive motor generator power inverter module with the latest software version. If the DTC resets replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator power inverter control module contains two motor control modules and the hybrid powertrain control module. Each motor control module operates its respective drive motor generator based upon hybrid powertrain control module commands. Each motor control module 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. Each drive motor generator operates utilizing 3 phase alternating current (AC) electricity. Each insulated gate bipolar transistors operate a single phase of the drive motor generator. Each phase is individually identified as U, V and W. Each motor control module monitors the current of each phase in order to detect drive motor generator power inverter control overcurrent conditions.

At ignition ON, each motor control module tests the integrity of the drive motor phase circuits by sequencing the insulated gate bipolar transistors between open and shorted states while simultaneously injecting a large amount of current into the phase circuits. The individual phase current sensors should all indicate similar current flow and the current flow should increase and decrease at known rates based upon the inductance of the drive motor.

1. The ignition is ON.
2. Ignition voltage is 8-18 V.
3. High voltage has been enabled.

The control module has detected a phase current that indicates an open or shorted condition exists in one or more of the 3 phase circuits.

1. DTCs P1AF8 and P1AFE are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P1AF8 and P1AFE are Type A DTCs.

1. An intermittent loss of battery power to the drive motor generator power inverter control module may set this DTC.
2. If the 3 phase cable terminal fasteners are not torque properly this DTC may set, and arc flash damage may occur. If any arc flash damage is present, replace all affected components.

Schematic Reference

Hybrid Controls Schematics

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Verify that DTC P1AF0, or P1AF2 is not set.

1. If the DTC is set, refer to «DTC P0AF7»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .

1. Verify that DTCs P0C01, P0C04, P0BFD, or P0BFE is not set. If the DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module cable connections.
3. Remove the 3-phase cable assembly from the T6 drive motor generator control module distribution box. Refer to «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
4. Test for less than 0.5 ohms between each of the AC circuit terminals listed below: Drive motor 1st position phase U and phase V terminal Drive motor 1st position phase V and phase W terminal Drive motor 2nd position phase U and phase V terminal Drive motor 2nd position phase V and phase W terminal If not the specified value, test the AC circuit for an open/high resistance. If the circuit tests normal replace the appropriate M15 drive motor with generator assembly.
5. Test for infinite resistance between each of the AC circuit terminals listed below and ground: Drive motor 1st position phase U terminal Drive motor 1st position phase V terminal Drive motor 1st position phase W terminal Drive motor 2nd position phase U terminal Drive motor 2nd position phase V terminal Drive motor 2nd position phase W terminal If not the specified value, test the AC circuit for a short to ground or a short between the AC circuit terminals and the aluminum cable mounting block. If the circuit tests normal replace the appropriate M15 drive motor with generator assembly.
6. Replace the 3 phase cable assembly and the appropriate M15 drive motor with generator assembly. If the DTC resets replace the T6 drive motor power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Generator Control Module 3-Phase Cable Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
2. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
4. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module and each motor control module utilize a programmable logic device to perform certain input and output functions. Motor control module 1 programs the programmable logic device with software at every ignition ON event. Motor control module 1 verifies that the programmable logic device is programmed successfully.

1. Ignition ON.
2. Ignition voltage is 8 V and no more than 18 V.

The control module has detected an internal programmable logic device malfunction.

1. DTC P1AFA is a Type A DTC.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTC P1AFA is a Type A DTC.

An intermittent loss of battery power to the drive motor generator power inverter module assembly may set this DTC.

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the hybrid powertrain control module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module and each motor control module utilize a programmable logic device to perform certain input and output functions. Motor control module 1 programs the programmable logic device with software at every ignition ON event. Motor control modules 1 and 2 verify that the programmable logic device is programmed successfully.

1. Ignition ON.
2. Ignition voltage is at least 8 V and no more than 18 V.

The control module has detected an internal programmable logic device malfunction.

1. DTCs P1AFB and P1B01 are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P1AFB and P1B01 are Type A DTCs.

An intermittent loss of battery voltage to the drive motor generator power inverter module assembly may set this DTC.

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the hybrid powertrain control module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This is an internal fault detection of the drive motor generator power inverter module. This fault is handled inside the hybrid powertrain control module and no external circuits are involved. The hybrid powertrain control module contains two motor control modules and the hybrid powertrain control module. These modules share dedicated internal drive motor generator power inverter module circuits. The modules listed below are part of the drive motor generator power inverter module and are not serviced separately.

1. Hybrid powertrain control module
2. Motor control module 1
3. Motor control module 2

1. The Ignition is ON.
2. The system voltage is 8-18 V.

P1AFC

Motor control module 1 detects a loss of SPI bus communication with the hybrid powertrain control module.

P1AFD

Motor control module 1 detects a loss of SCI bus communication with motor control module 2 for 2 seconds.

P1B02

Motor control module 2 detects a loss of SPI bus communication with the hybrid powertrain control module.

1. DTCs P1AFC and P1B02 are Type A DTCs.
2. DTC P1AFD is a Type B DTC.
3. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

1. DTCs P1AFC and P1B02 are Type A DTCs.
2. DTC P1AFD is a Type B DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed and direction of the drive motor generator based upon the signals of the resolver-type position sensor. The position sensor allows the motor control module to determine the exact position, speed and direction of the drive motor generator.

1. Ignition voltage is 8-18V.
2. Motor control module temperature and voltage out of range DTCs have not set.
3. Drive motor generator speed greater than 11, 500 RPM.

The motor control module detects drive motor generator speed greater than 10, 000 RPM after an initial detection of greater than 11, 500 RPM.

1. DTCs P1B0D and P1B0E are Type A DTCs.
2. The hybrid powertrain control module commands the battery energy control module to open the high voltage contactor relays.

DTCs P1B0D and P1B0E are Type A DTCs.

1. The drive axle and drive motor generator 2 are joined mechanically through a planetary gear set, any condition that allows the rear axle to rotate too fast while the transmission is in gear may cause DTC P1B0E to set. Ask the operator if the vehicle was subjected to downhill coasting at an excessive speed.
2. A transmission mechanical failure that occurs during high drive motor generator torque may cause these DTCs to set.
3. Repeated drive motor generator operation at speeds in excess of the DTC limits may cause deterioration of the drive motor generator magnets.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTC P0723 is not set. If the DTC is set, refer to «DTC P0721-P0723»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-diagnostic-information-and-procedures) .
2. Verify there is no other hybrid Transmission DTCs set. If other Hybrid Transmission DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
3. Ignition OFF for at least one minute. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. Verify that DTCs P1B0D or P1B0E is not set.
4. If DTCs P1B0D or P1B0E is set, program the drive motor generator power inverter module with the latest software version. If the DTC resets replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The drive motor generator position sensor is monitored by the motor control module. The motor control module monitors the angular position, speed and direction of the drive motor generator rotor based upon the signals of the resolver-type position sensor. The position sensor contains a drive coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At ignition ON, the motor control module outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field surrounding the two driven coils and the irregular shaped rotor. The motor control module then monitors the two driven coil circuits for a return signal. The position of the irregular metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A comparison of the two driven coils signals allows the motor control module to determine the exact position, speed and direction of the drive motor generator rotor. The position sensor is a non-serviceable part of the drive motor generator.

A measurement called offset is needed for accurate determination of the motor position. Offset is the relationship between the position sensor and the drive motor generator output shaft. Whenever the ignition is cycled to OFF, the motor control module attempts to learn the offset of the drive motor position sensor by rapidly oscillating the motor and observing the position sensor signals.

Condition 1, 2, 3 and 4

1. Hybrid wake-up signal is not active because the ignition has been transitioned from RUN to OFF.
2. The motor control module has learned a valid drive motor position sensor offset value at least once.

Condition 2

Motor speed is less than 20 RPM.

Condition 1

Position sensor offset value not learned because drive motor speed is greater than 50 RPM.

Condition 2

Position sensor offset value not learned because hybrid battery voltage as observed at the motor control module is less than 192V.

Condition 3

Position sensor offset value not learned because drive motor phase to phase current difference is less than 15 A.

Condition 4

Position sensor offset value not learned because the offset learn value is greater than the maximum allowed offset of 25 degrees.

1. DTCs P1B10 and P1B0F are Type C DTCs.
2. The motor control module operates the drive motor generator using the last valid learned offset.

1. DTCs P1B10 and P1B0F are Type C DTCs.
2. High voltage remains enabled immediately following an ignition key transition from RUN to OFF.

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, verify that DTCs P0A40, P0A45, P0A46, P0A78, P0A79, P0A3F, P0C05, P0C08, P0C0B, P0C0E, P0C4E, P0C4F, P0C52, P0C53, P0C57, P0C58, P0C61, P0C62, P0C5C, P0C5D, P1B03, P1B04 or P1B0D is not set. If DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Ignition ON, engine OFF, observe the scan tool battery energy control module contactor system status parameter. The status should display closed. If not the specified value, refer to «Symptoms - Hybrid Controls»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__symptoms-hybrid-controls) .
3. Cycle the ignition OFF for 2 minutes, ON for 2 minutes then OFF for at least 10 seconds.
4. Ignition ON, Verify that DTCs P1B10 or P1B0F is not set. If the DTC is set, program the T6 drive motor generator power inverter module. If the DTC resets, replace the appropriate M15 drive motor with generator assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Drive Motor with Generator Assembly Removal - 1st Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
2. «Drive Motor with Generator Assembly Removal - 2nd Position»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-off-vehicle)
3. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Drive Motor Generator Power Inverter Module replacement, setup and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the hybrid powertrain control module. The hybrid powertrain control module is internal to the power inverter module, often referred to as the drive motor generator power inverter module, and is not serviced separately. The hybrid powertrain control module monitors its ability to read and write to the memory. The hybrid powertrain control module processor monitors the data to verify that the indicated brake torque request calculation is correct.

1. The vehicle is ON for 1 second.
2. The system voltage is 8-18 V.

The control module has detected an internal malfunction.

1. DTC P1B15 is a Type A DTC.
2. The hybrid powertrain control module requests the hybrid powertrain control module 2 to open the high voltage contactor relays.

DTC P1B15 is a Type A DTC.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

If the DTC is set, program the T6 power inverter module. If the DTC resets, replace the T6 power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module, also called the power inverter module, replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hybrid powertrain control module uses ignition 1 circuit terminal voltage to monitor the 12V system voltage. Ignition 1 circuit voltage also powers several of the internal drive motor generator power inverter control module drive motor generator power inverter module components.

Ignition is ON.

The control module has detected ignition 1 circuit voltage is less than 2V.

1. DTC P2534 is a Type A DTC.
2. The hybrid powertrain control module commands the engine OFF.

DTC P2534 is a Type A DTC.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Ignition OFF, disconnect the T6 drive motor generator power inverter module connector X1.
2. Ignition ON, measure the voltage on the ignition 1 circuit, between connector X1 terminal 20 and ground. The voltage should be within 1.0 V of the battery voltage. If not the specified value test the ignition 1 signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Aux. Trans. Fluid Pump Fault Status 1

Aux. Trans. Fluid Pump Fault Status 2

The auxiliary transmission fluid pump system supplies the transmission with hydraulic pressure when the vehicle is operating in the internal combustion engine Autostop hybrid mode. The auxiliary transmission fluid pump system consists of an auxiliary transmission fluid pump control module that operates an electric, 12V 3 phase alternating current (ac), motor-driven pump. Two pulse width modulated (PWM) status circuits connect the auxiliary transmission fluid pump control module to the hybrid powertrain control module. The transmission auxiliary oil pump control circuit delivers the hybrid powertrain control module commanded pump speed to the auxiliary transmission fluid pump control module. The transmission auxiliary oil pump diagnostic circuit supplies the hybrid powertrain control module with the actual pump speed and also with the operating status of the auxiliary transmission fluid pump control module. The hybrid powertrain control module monitors these circuits for fault conditions.

The auxiliary transmission fluid pump control module inverts 12V direct current (dc) into 12v 3 phase ac current to operate the pump motor.

The auxiliary transmission fluid pump control module monitors the status of the auxiliary transmission fluid pump motor/pump as well as its own internal circuitry. The auxiliary transmission fluid pump control module does not store its own diagnostic status. Current ignition cycle diagnostic status is reported to the hybrid powertrain control module over the transmission auxiliary oil pump diagnostic circuit. The diagnostic status within the auxiliary transmission fluid pump control module is reset at every ignition-off cycle.

1. Ignition voltage is 8-18 volts.
2. The auxiliary transmission fluid pump is commanded ON.

The hybrid powertrain control module observes the difference between actual and commanded auxiliary transmission fluid pump pump speed is greater than 500 RPM for 4 out of 4.125 seconds.

1. DTC P2797 is a Type B DTC.
2. The drive motor generator power inverter control module disables the Autostop hybrid mode.

DTC P2797 is a Type B DTC.

Inquire with the customer the detailed driving conditions which caused the DTC to set

1. Does the condition improve after a given length of time driving, or is it worse after setting over night, or does it occur regardless of drive time or conditions?
2. During Autostop/Autostart event?
3. During braking coming to a stop, or upon launch from a stop, low vehicle speed when IC engine is off?

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Signal Generator

For equivalent regional tools, refer to Special Tools .

1. Inspect for DTC P0C2B. Diagnose DTC P0C2B before performing this procedure.
2. «Transmission Fluid Level and Condition Check»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-diagnostic-information-and-procedures__transmission-fluid-level-and-condition-check) .
3. With vehicle in Autostop, observe the aux. trans. fluid pump actual, aux. trans. fluid pump commanded, and fault status displays with the scan tool. If a fault status is observed, refer to Circuit/System Testing below.

1. Ignition ON, engine OFF, observe the Aux. Trans. Fluid Pump Fault Status 1 and Aux. Trans. Fluid Fault Status 2 displays with the scan tool. If there is a fault currently active, refer to the applicable diagnostic procedure below for the fault status indicated by the scan tool display.
2. Using the scan tool, command the aux. trans. fluid pump speed to 50 percent and maintain pump operation for at least 60 seconds while observing the fault status displays. The actual pump speed should be maintained within 10 percent of commanded. The pump should not make excessive noise or stall. If there is a fault currently active as a result of the manual speed command test, refer to the applicable diagnostic procedure below for the fault status indicated by the scan tool display. If the actual speed is within 10 percent of commanded speed an aux. trans. fluid pump pressure fault could be present, test the aux. trans. pump line pressure output. Refer to «Line Pressure Check»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-diagnostic-information-and-procedures__line-pressure-check) . If there is not a fault currently active as a result of the manual speed command test, and DTC P2797 is either active or in history, review the Freeze Frame/Failure Records for the DTC and perform the diagnosis indicated by the Fault Status parameter display within the Freeze Frame/Failure Records.
3. Perform an aux pump stress drive cycle, following an 8 hour ambient soak: Apply parking brake While in Autostop, recreate the condition by brake torquing to achieve motor 2 torque between 110-160 N.m (81-118 lb ft). Maintain for at least 30 seconds and release pedal for approximately 10 seconds, repeat test at least 10 times while observing the following parameters: Pump Speed Control Module Voltage, should be at least 12V Aux. Trans. Fluid Pump Fault Status 1 and 2 If the difference between actual and commanded speed is greater than 10 percent, the pump is noisy, or the pump stalls, refer to Circuit/System Testing below.
4. If the customer's concern can not be duplicated and No Fault status is displayed, the failure is likely related to a faulty auxiliary transmission fluid pump control module and therefore the module should be replaced.

PWM Input Fault

1. Ignition OFF, disconnect power inverter module connector X1.
2. Ignition ON, test for 11-13V on the Trans. Aux. Oil Pump Control circuit from power inverter module connector X1 terminal 5 and chassis ground. If less than the specified range, test the control circuit for an open or short to ground. If the circuit tests normal, replace the auxiliary transmission fluid pump Control Module.
3. Pre-Adjust the J 38522 variable signal generator to 50 percent duty cycle @ 250 Hz.
4. Connect the J 38522 variable signal generator to the Trans. Aux. Oil Pump Control circuit, from the power inverter module connector X1 terminal 5 and ground and listen for auxiliary transmission fluid pump motor operation. If pump operation is audible, replace the power inverter module. If pump operation is not audible, continue with Circuit/System Testing.
5. Ignition OFF, disconnect the auxiliary transmission fluid pump control module connector X1.
6. Ignition ON, test for 0V on the Trans. Aux. Oil Pump control circuit from power inverter module connector X1 terminal 5 and chassis ground. If greater than the specified range, test the control circuit for a short to voltage. If equal to the specified range, replace the auxiliary transmission fluid pump control module.

Motor/Open Short

This display indicates the auxiliary transmission fluid pump control module has detected one of the following pump motor current conditions

1. At least one phase current is more than 70 A.
2. Commanded current is more than 5 A and actual current in any phase is less than 2 A.

1. Ignition OFF, disconnect the auxiliary transmission fluid pump control module connector X2.
2. Inspect both connectors for TPA and terminal tension / retention, backed out terminals, discoloration, etc.
3. Using the Auxiliary Fluid Pump Specification table listed below, test the resistance between the X2 circuits of the pump connector as indicated. If any of the circuits are not within the specified range, replace the pump assembly and repeat the Circuit/System Verification. If all circuits test normal, replace the auxiliary transmission fluid pump control module and repeat Circuit/System Verification.

Auxiliary Fluid Pump Specification

Motor CKT Fault

This display indicates an internal auxiliary transmission fluid pump control module fault exists, no external circuits are involved. Test pump circuits for a short to ground before replacing controller and test controller circuits for a short to ground.

1. Test the following auxiliary transmission fluid pump circuits for a short to ground: Auxiliary transmission fluid pump phase A X2 terminal 1 Auxiliary transmission fluid pump phase B X2 terminal 2 Auxiliary transmission fluid pump phase C X2 terminal 3 If the auxiliary transmission fluid pump is shorted to ground, replace auxiliary transmission fluid pump.
2. Test the following auxiliary transmission fluid control module circuits for a short to ground: Auxiliary transmission fluid pump control module phase A X2 terminal 1 Auxiliary transmission fluid pump control module phase B X2 terminal 2 Auxiliary transmission fluid pump control module phase C X2 terminal 3 If the transmission fluid pump control module is shorted to ground, replace the transmission fluid pump control module.

If the circuits test normal, replace the auxiliary transmission fluid pump and the auxiliary transmission fluid pump control module.

Temp Sen Fault

This display indicates an internal auxiliary transmission fluid pump control module fault exists, no external circuits are involved. Replace the auxiliary transmission fluid pump control module.

Low Voltage

This display indicates the auxiliary transmission fluid pump control module has monitored battery voltage less than desired operating voltage.

1. Measure actual battery voltage with a DMM at both the 12 volt battery and the DC supply harness to the auxiliary transmission fluid pump control module. If actual battery voltage measures less than the value range, proceed to step 2. If actual battery voltage measures more than the value range, test the auxiliary transmission fluid pump control module power and ground circuits for a high resistance condition. If the circuits test normal, replace the auxiliary transmission fluid pump control module.
2. Verify 12V battery and accessory DC Power conversion control module condition, «Accessory DC Power Control Module Scan Tool Information»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-specifications-scan-tool-information-1-of-2__accessory-dc-power-control-module-scan) .

Auxiliary Transmission Fluid Pump Control Module Over temp

This display indicates an internal auxiliary transmission fluid pump control module fault exists, no external circuits are involved. Replace the auxiliary transmission fluid pump control module.

Auxiliary Transmission Fluid Pump Control Module Hot

This display indicates an internal auxiliary transmission fluid pump control module fault exists, no external circuits are involved. Replace the auxiliary transmission fluid pump control module.

Current High/Lo

1. This display indicates the auxiliary transmission fluid pump control module has monitored motor current that is outside the normal range for a given motor speed.
2. Inspect for the following conditions: Low or cavitating automatic transmission fluid - Verify line pressure Poor terminal connection or wiring degradation, controller and pump External indication of auxiliary transmission fluid pump pump motor damage If none of the conditions are observed, replace the auxiliary transmission fluid pump.

Current Fault

This display indicates an internal auxiliary transmission fluid pump control module fault exists, no external circuits are involved. Replace the auxiliary transmission fluid pump control module.

No Start

This display indicates the auxiliary transmission fluid pump control module has monitored excess motor current during motor start-up.

Inspect for the following conditions

1. Automatic transmission fluid pressure trapped internally, verify line pressure check is normal
2. Poor terminal connection or wiring degradation
3. External indication of auxiliary transmission fluid pump pump motor damage If none of the conditions are observed, replace the auxiliary transmission fluid pump control module.

No PWM Response

This display indicates the hybrid powertrain control module does not detect the auxiliary transmission fluid pump Control Feedback circuit signal. Refer to DTC P0C2B .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for auxiliary transmission fluid pump control module replacement, setup, and programming
2. «Auxiliary Fluid Pump and Gasket Replacement»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle)

Symptoms - Hybrid Controls

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following procedures: «Drive Motor Generator Control Module Description and Operation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) «High Voltage Monitoring Systems Description»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__high-voltage-monitoring-systems-description) «Hybrid Modes of Operation Description»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__hybrid-modes-of-operation-description) «Drive Motor Battery System Description»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system) «Transmission General Description»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-description-and-operation__transmission-general-description)

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Hybrid System. Refer to «Checking Aftermarket Accessories»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Engine Will Not Crank»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)
2. «Engine Does Not AutoStop»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system)

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This vehicle does not use a 12V starter motor to crank the internal combustion engine. A much more powerful 300V motor generator located within the transmission is utilized to crank the engine. The 300V motor generator can rotate the engine to operating speed, 800 RPM, within just a few hundred milliseconds. The 300V motor generator allows near-instant starting of the engine.

The body control module (BCM) monitors the position of the ignition switch. When the ignition switch is placed in the Crank position, the BCM sends out a Crank-Request message over GMLAN. The hybrid powertrain control module responds to this GMLAN message by applying torque to drive motor generator 1 located within the transmission. Drive motor generator 1 is mechanically linked to the engine crankshaft.

The hybrid powertrain control module will not respond to the BCM Crank-Request GMLAN message if certain vehicle conditions exist such as the transmission gear selector position does not equal Park or Neutral or certain DTCs are set.

1. Ensure the range selector lever is in Park or Neutral.
2. Turn the ignition key to crank.
3. The engine should instantly crank and run. If the engine starts and runs, the system is operating normally.

1. Verify no hybrid powertrain control module or engine control module (ECM) DTCs are set that would disable high voltage or that identify a gear selector switch concern. If the specified DTCs are set, repair them first. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Observe the battery energy control module Contactor System Status parameter. You should observe contactor status as Closed. If the parameter displays Precharge Inhibit, the battery energy control module is operating in the precharge resistor protection mode and high voltage has been disabled for 35 minutes. Observe the battery energy control module Precharge Wait Time parameter to determine the amount of disable time remaining. Turn the ignition OFF and wait the applicable amount of time before attempting to crank the engine.
3. Observe the hybrid powertrain control module IMS Range parameter display with a scan tool. The display should indicate Park or Neutral. If the display does not indicate Park or Neutral, adjust the range selector lever cable. Refer to «Range Selector Lever Cable Adjustment»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle__range-selector-lever-cable-adjustment) .
4. Verify that serial data gateway module DTC B009F is not set. If B009F is set, refer to «DTC B009F»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
5. Observe the serial data gateway module Hybrid Crash Status parameter. If the vehicle has not been involved in a collision the parameter should display No Crash. If the parameter displays Crash Detected and/or the vehicle has been involved in a collision the high voltage system should be inspected for damage before the high voltage system is re-enabled. Refer to «High Voltage System Inspection»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
6. Verify the vehicle has not been in a collision that resulted in supplemental inflatable restrain (SIR) deployment. If SIR deployment has occurred the high voltage system should be inspected for damage before the high voltage system is re-enabled. Refer to «High Voltage System Inspection»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
7. Observe the battery energy control module Hybrid Battery Pack Calculated voltage parameter with a scan tool. You should observe greater than 305 volts. If the hybrid battery voltage is less than the specified value, attempt to charge the Hybrid Battery. Refer to «Jump Assist»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system) .
8. Observe the battery energy control module Hybrid Battery state of charge parameter with a scan tool. You should observe greater than 20 % hybrid battery state of charge. If the hybrid battery state of charge is the same or less than the specified value, attempt to charge the Hybrid Battery. Refer to «Jump Assist»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system) .
9. Turn the ignition to Crank. The engine should instantly start and run. If the engine does not crank but audible transmission noise is observed while cranking, inspect the transmission for internal component failure. A seized engine or accessory drive could cause transmission damage during engine crank. If the engine does not crank and no audible transmission noise is observed, continue with diagnosis.
10. Perform the hybrid powertrain control module scan tool Clear 300V Impact Detection DTC output control. Turn the ignition OFF for 60 seconds.
11. Turn the ignition to Crank. The engine should instantly start and run. If the engine cranks, the DTC Information for serial data gateway module DTC B009F had been previously cleared without performing the scan tool output control. Ensure DTC B009F runs and passes. If the engine does not crank, continue with diagnosis.
12. Perform the hybrid powertrain control module scan tool Clear 300V Present DTC output control. Turn the ignition OFF for 5 minutes.
13. Turn the ignition to Crank. The engine should instantly start and run. If the engine cranks, the DTC Information for DTC P0C76 had been previously cleared without performing the scan tool output control. Ensure DTC P0C76 runs and passes. If the engine does not crank, replace the drive motor generator power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for power inverter module replacement, setup, and programming.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Autostop Inhibit Reasons

This vehicle does not use a 12V starter motor to crank the internal combustion engine. A much more powerful 300V motor/generator located within the transmission is utilized to crank the engine. The 300V motor/generator can rotate the engine to operating speed, 800 RPM, within just a few hundred milliseconds. The 300V motor/generator allows near-instant starting of the engine. Once started, engine operation may cycle between Autostop, engine off, and Autostart, engine running, for the duration of the drive trip.

Autostop/Autostart

The Two-Mode Hybrid vehicle does not require internal combustion engine operation at all times. After a successful engine start, the hybrid powertrain control module may turn off the engine, or Autostop, when not required for the current vehicle conditions. The engine will remain off while in Autostop mode, until such time that vehicle conditions require the engine to run. The near-instant starting of the engine from Autostop mode is called Autostart.

Autostop Conditions

Numerous conditions must all be within acceptable limits in order for the hybrid powertrain control module to allow the Autostop hybrid mode. The Typical Scan Tool Data information lists the vehicle conditions required for Autostop operation.

A chime will sound if the drivers door is opened while in Autostop as a reminder that the engine is not in the OFF mode.

Engine OFF and AUTO STOP modes are indicated on the tachometer display.

1. When the tachometer needle indicates OFF, the engine is not running and will remain Off until the ignition key is placed in the Crank position or a remote vehicle start request is received from the keyless entry transmitter. Autostop is not allowed with a remote vehicle start.
2. When the tachometer needle indicates AUTO STOP, the engine is not running but may Autostart at any time without notice.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Hood closed, start the engine with the ignition key and allow to idle.
2. Monitor engine operation and the tachometer display for 5 minutes.
3. The vehicle should enter the Autostop hybrid mode. If the vehicle operates in the Autostop hybrid mode, the system is operating normally. If the vehicle cycles rapidly in and out of the Autostop hybrid mode, test the auxiliary transmission fluid pump pressure. Refer to «Line Pressure Check»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-diagnostic-information-and-procedures__line-pressure-check) . If the vehicle does not operate in the Autostop hybrid mode, continue to Circuit/System Testing.

1. Verify no hybrid powertrain control module or ECM DTCs are set. Repair any hybrid powertrain control module or ECM DTCs prior to performing this diagnostic procedure.
2. Engine at idle, observe the hybrid powertrain control module Autostop Inhibit Reasons scan tool parameter.
3. Compare the parameter display to the Typical Scan Tool Data information.
4. Identify which Autostop inhibit conditions have prohibited Autostop operation. An Inhibit condition will display YES on the scan tool.
5. Determine if the Autostop inhibit conditions are the result of normal operating conditions or the result of a fault condition. Repair the conditions that are the result of a fault condition. For example, a hood switch that indicates hood status as open when the hood is actually closed. Advise the vehicle operator of the normal operating and environmental conditions that will inhibit Autostop. For example, advise that Autostop is disabled when hybrid Battery Pack temperature is less than 10°C (50°F).

High Voltage System Diagnosis (EL-48458)

Special Tools

EL-48458 Pre-Charge Tester

Description and Operation

The EL-48458 pre-charge tester is a device designed to assist in the diagnosis of fault conditions that may be difficult to differentiate between in the drive motor generator battery and the power inverter module. The internal workings of the pre-charge tester include high voltage bulk capacitors to simulate the capacitance of the power inverter module. In addition, there are electronic components designed to mimic the redundant contactor pulse width modulated (PWM) command circuit in order to facilitate the closing and opening of the drive motor generator battery contactors without a power inverter module. The pre-charge tester also incorporates High Voltage Circuit LED indicators to alert the operator of the presence of high voltage to encourage safe operation.

The EL-48458 pre-charge tester may be connected to the vehicle at either the power inverter module high voltage connection or at the drive motor generator battery high voltage terminal connection depending upon service information procedures.

Installation Procedure When Testing at the Power Inverter Module

1. Ignition OFF, perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator control module assembly.
2. Disconnect and remove the air conditioning compressor high voltage cables from the high voltage distribution box.
3. Disconnect and remove the drive motor generator battery high voltage cables from the high voltage distribution box. Remove and retain the cable mounting block O-ring. Re-install the O-ring after testing is complete.
4. Connect the drive motor generator battery high voltage cable assembly to the EL-48458 pre-charge tester. Ensure that the high voltage terminal cover on the EL-48458 pre-charge tester is closed after connecting the high voltage cable assembly.
5. Place the EL-48458 pre-charge tester contactor duty cycle switch in the Open Position.
6. Remove the drive motor generator control module sight shield HVIC connector from the power inverter module mounting block.
7. Disconnect the 56-way connector from the power inverter module and connect the vehicle harness side connector to the EL-48458 pre-charge tester.
8. Connect the EL-48458 pre-charge tester HVIC connector to the drive motor generator control module sight shield HVIC connector.
9. Connect the alligator clip on the EL-48458 pre-charge tester to a 12-volt vehicle chassis ground point.
10. Install the high voltage manual disconnect lever.
11. Connect the 12-volt battery.
12. Turn the Ignition Key to RUN. The Ignition ON LED on the EL-48458 pre-charge tester should illuminate. If the Ignition ON LED does not illuminate, verify the alligator clip connection to ground, then remove the 56-way connector and confirm with a DMM that the 12 volt ignition circuit is supplying the proper voltage to power inverter module connector X1 terminal 9 when the ignition key is in RUN. If 12 V battery voltage is measured at power inverter module connector X1 terminal 9 then the EL-48458 pre-charge tester is not functioning and must be replaced.
13. Perform any tests and/or diagnostics as needed.

Removal Procedure When Testing at the Power Inverter Module

1. Move the EL-48458 pre-charge tester High Voltage Contactor Relay switch to the Open Position.
2. The high voltage stored within the EL-48458 pre-charge tester internal capacitors should begin to discharge. After about 20 seconds. the HI VOLTAGE CIRCUIT indicator LEDs should operate in the following manner: The Greater Than 60 Volts When Lit LED should turn OFF. The Less Than 60 Volts When Lit LED should briefly illuminate. The Less Than 60 Volts When Lit LED should turn OFF.
3. Turn the Ignition Key to OFF.
4. Disconnect the 56-Way connector from the EL-48458 pre-charge tester and the alligator clip from the ground connection. Leave the high voltage terminal cover closed.
5. Disconnect the EL-48458 pre-charge tester high voltage interlock circuit (HVIC) connector from the drive motor generator control module sight shield HVIC connector.
6. Wait 5 minutes.
7. Perform the high voltage disabling procedure. Refer to «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) .
8. While still wearing your personal protection equipment, open the EL-48458 pre-charge tester high voltage terminal cover and measure the high voltage terminal connections with a DMM using the following procedure: Set the voltmeter to DC mode. Verify the voltmeter works by measuring the voltage of the 12-volt battery. Using the voltmeter, verify the voltage measures less than 3 volts across the HVDC (+) positive and HVDC (-) negative terminals. If the test result was more than 3 volts, the EL-48458 pre-charge tester internal capacitors are still charged. Keep the isolation gloves on and install the high voltage terminal cover. Wait 5 minutes and then remove the cover and return to the beginning of this step.
9. When voltage is no longer present, disconnect the high voltage cables from the EL-48458 pre-charge tester and remove the tool from the vehicle.
10. Re-assemble the vehicle as instructed in the diagnostic procedure.

Installation Procedure When Testing at the Drive Motor Generator Battery Assembly

1. Ignition OFF, perform the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure for servicing at the drive motor generator battery assembly or 300V DC cables.
2. Remove the 300V DC cables from the drive motor generator battery assembly.
3. Attach the EL-48458 pre-charge tester high voltage jumper to the drive motor generator battery high voltage terminals. Ensure proper polarity connection by connecting the orange and black stripe wire to the negative terminal.
4. Install the terminal extension cover assembly with the fasteners. Tighten the fasteners finger-tight.
5. Insert the high voltage jumper connector into the EL-48458 pre-charge tester. Ensure that the high voltage terminal cover on the EL-48458 pre-charge tester remains closed.
6. Place the EL-48458 pre-charge tester contactor duty cycle switch in the Open Position.
7. Remove the 56-way connector from the power inverter module and connect the vehicle harness side connector to the EL-48458 pre-charge tester.
8. Remove the drive motor generator control module sight shield HVIC connector from the power inverter module mounting block.
9. Connect the EL-48458 pre-charge tester HVIC connector to the drive motor generator control module sight shield HVIC connector.
10. Connect the alligator clip on the EL-48458 pre-charge tester to a 12-volt vehicle chassis ground point.
11. Install the high voltage manual disconnect lever.
12. Connect the 12-volt battery.
13. Turn the Ignition Key to RUN. The Ignition ON LED on the EL-48458 pre-charge tester should illuminate. If the Ignition ON LED does not illuminate, verify the alligator clip connection to ground, then remove the 56-way connector and confirm with a DMM that the 12 volt ignition circuit is supplying the proper voltage to power inverter module connector X1 terminal 9 when the ignition key is in RUN. If 12 V battery voltage is measured at power inverter module connector X1 terminal 9 then the EL-48458 pre-charge tester is not functioning and must be replaced.
14. Perform any tests and/or diagnostics as identified by the service information procedure.

Removal Procedure When Testing at the Drive Motor Generator Battery Assembly

1. Move the EL-48458 pre-charge tester High Voltage Contactor Relay switch to the Open Position.
2. The high voltage stored within the EL-48458 pre-charge tester internal capacitors should begin to discharge. After about 20 seconds. the HI VOLTAGE CIRCUIT indicator LEDs should operate in the following manner: The Greater Than 60 Volts When Lit LED should turn OFF. The Less Than 60 Volts When Lit LED should briefly illuminate. The Less Than 60 Volts When Lit LED should turn OFF.
3. Turn the Ignition Key to OFF.
4. Disconnect the 56-Way connector from the EL-48458 pre-charge tester and the alligator clip from the ground connection. Leave the high voltage terminal cover closed.
5. Disconnect the EL-48458 pre-charge tester high voltage interlock circuit (HVIC) connector from the drive motor generator control module sight shield HVIC connector.
6. Wait 5 minutes.
7. Perform the high voltage disabling procedure. Refer to «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) .
8. While still wearing your personal protection equipment, open the EL-48458 pre-charge tester high voltage terminal cover and measure the high voltage terminal connections with a DMM using the following procedure: Set the voltmeter to DC mode. Verify the voltmeter works by measuring the voltage of the 12-volt battery. Using the voltmeter, verify the voltage measures less than 3 volts across the HVDC (+) positive and HVDC (-) negative terminals. If the test result was more than 3 volts, the EL-48458 pre-charge tester internal capacitors are still charged. Keep the isolation gloves on and install the high voltage terminal cover. Wait 5 minutes and then remove the cover and return to the beginning of this step.
9. When voltage is no longer present, disconnect the high voltage cables from the EL-48458 pre-charge tester and remove the tool from the vehicle.
10. Remove the terminal extension cover and the EL-48458 pre-charge tester high voltage jumper from the drive motor generator battery assembly.
11. Re-assemble the vehicle as instructed in the diagnostic procedure.

1. Perform the «Diagnostic System Check - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory DC power control module supplies the energy that flows between the high voltage (300 volt) direct current (DC) and low voltage (14 volt) DC to charge the 12 volt battery and power accessories. The accessory DC power control module receives a wake-up signal on a discrete line from the serial data gateway module when the key is turned to RUN. After a successful engine start, the accessory DC power control module receives an enable command from the hybrid powertrain control module over the high speed hybrid GMLAN communication circuit to begin power conversion.

A poor connection at the B+ terminal of the accessory DC power control module or blown 200 Amp Mega-Fuse in the hybrid Bussed Electrical Center will prevent the accessory DC power control module from powering up and all values in the accessory DC power control module data list will read zero on the scan tool.

A poor connection on the accessory DC power control module wake-up signal X1 Terminal 3 from the serial data gateway module will also prevent the accessory DC power control module from powering up and all data values in the accessory DC power control module data list will read zero on the scan tool.

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Drive Motor Generator Control Module Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Engine ON, observe the charge indicator on the instrument panel cluster or message in the driver information center. The charge indicator on the instrument panel cluster should be turned OFF and the driver information center should not display charging system message.

1. If the charge indicator is not on the instrument panel cluster or a charging system message is not displayed on the driver information center, refer to «Testing for Intermittent Conditions and Poor Connections»(/gmc/sierra-2500/2012-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) .
2. If the charge indicator is on the instrument panel cluster or a charging system message is displayed on the driver information center, refer to Circuit/System Testing below.

1. Ignition ON, verify that no generator or battery current sensor DTCs are set that would cause a charging system concern. If DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/gmc/sierra-2500/2012-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
2. Ignition OFF, measure the voltage across the battery terminals. The voltage should read 12.0 volts or greater at room temperature. If not within specified value, refer to «Battery Inspection/Test»(/gmc/sierra-2500/2012-2012/remont/charging-system/#engine-electrical-battery-hybrid-hp2) .
3. Connect a carbon pile tester to the battery.
4. Start the engine and turn all accessories off. Observe the voltage reading on the tester. The voltage should read between 12.6-15.5 volts.
5. Adjust the carbon pile tester so that the 12 volt current on the accessory DC power control module data list is reading 175 amps. If not within specified value, replace the accessory DC power control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for accessory DC power control module replacement, setup and programming.

Vehicle Collision Detection

This vehicle contains a high voltage circuit impact detection (HVCID) sensor in addition to the supplemental inflatable restraint (SIR) impact sensors. The SIR sensors are designed to identify the severity of a collision and from what direction a collision has occurred. The SIR sensors typically detect collision conditions for occupant impact-protection reasons. The HVCID sensor is located in the front of the vehicle and is designed to detect an offset collision that may have damaged the high voltage system. The drive motor generator control module, also called the hybrid powertrain control module (HPCM), will open the high voltage contactor relays and disable the vehicle whenever an SIR deployment occurs or the HVCID sensor detects a collision event. The HVCID sensor detection of a vehicle impact does not cause SIR deployment.

The serial data gateway module (SDGM) monitors the HVCID sensor for collision/impact detection and operational status. The SDGM transmits a GMLAN message to the HPCM whenever an HVCID impact event or sensor fault is detected.

A complete inspection of the high voltage (HV) system and components must be performed if the vehicle has been involved in a collision. The HVCID sensor and/or SIR Deployed vehicle-disable condition will remain active until cleared by the HPCM output control function of the scan tool.

Inspection Procedure

1. Perform the high voltage disable procedure at the drive motor generator battery cable connections. Refer to «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) . If vehicle damage does not allow access to the high voltage manual disconnect, disconnect the 12V battery and remove the damaged portion of the vehicle until such time as the HV manual disconnect can be removed and the «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) procedure can be completed.
2. Perform a visual inspection of the HV DC 300V cables between the drive motor generator power inverter module (PIM) and the drive motor generator battery assembly. Inspect for pinched, cut or frayed cables. Record any observed damage and continue.
3. Perform a visual inspection of the HV DC 300V cables between the PIM and the air conditioning compressor. Inspect for pinched, cut or frayed cables. Record any observed damage and continue.
4. Perform a visual inspection of the 3 phase cables between the PIM and the transmission case. Inspect for pinched, cut or frayed cables. Inspect the conduit for kinks or dents. Record any observed damage and continue.
5. Perform a visual inspection of the 42V power steering cables between the accessory DC power control module (APM) and the power steering control module (PSCM). Inspect for pinched, cut or frayed cables. Record any observed damage and continue.
6. Perform a visual inspection of the drive motor generator control module assembly. Inspect the assembly for cracks, dents or other physical damage. Record any observed damage and continue.
7. Perform a visual inspection of the air conditioning compressor assembly. Inspect the assembly for cracks, dents or other physical damage. Record any observed damage and continue.
8. Perform a visual inspection of the transmission assembly. Inspect the assembly for cracks, dents or other physical damage. Record any observed damage and continue.
9. Perform a visual inspection of the drive motor generator battery assembly. Inspect the assembly for cracks, dents or other physical damage. Record any observed damage and continue.
10. Replace all components identified as damaged. With a scan tool clear the HVCID and/or SIR Deployed vehicle disable condition only after all high voltage components identified as damaged have been replaced.

HVCID and/or SIR Deployed Vehicle Disable Condition Clearing Procedure

1. Perform the Inspection Procedure if the vehicle has been involved in a collision.
2. Ignition ON, clear the SDGM vehicle disable condition with a scan tool. If the SDGM had a HVCID sensor fault DTC, repair the condition and clear SDGM DTC Information. If the SDGM had an HVCID collision detection condition, perform the SDGM Crash Sensor Reset special function.
3. Ignition OFF, wait 2 minutes.
4. Ignition ON, clear the HPCM vehicle disable condition with the scan tool HPCM Clear 300V Impact Detection Status special function.
5. Ignition OFF, wait 2 minutes.
6. Perform the HV Enable Procedure. Refer to «High Voltage Enabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-enabling) .

Scheme 12

High Voltage Circuit Impact Detection Sensor Replacement

Removal Procedure

1. Perform the high voltage disabling. Refer to «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) .
2. Remove the power inverter module (PIM) 3 phase cable terminal fasteners (1).
3. Remove the PIM 3 phase cable mounting fasteners (2, 4).
4. Remove the PIM 3 phase cables (3, 5) from the PIM distribution box.
5. Remove and discard the seals (6).
6. Remove the 3 phase cable retainer nut (2).
7. Remove the 3 phase cable retainer (1) from the bracket.
8. Remove and lower the transmission enough to gain access to the 3 phase cable bracket bolts (1). Refer to «Transmission Replacement»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle__transmission-replacement) .
9. Remove the 3 phase cable bracket bolts (1).
10. Remove the 3 phase cover bolts (9) and transmission cover terminal housing (8).
11. Remove the 3 phase cover (7).
12. Disconnect the 3 phase cable cover connector.
13. Remove the 3 phase cable bolt protective cover (5).
14. Remove the 3 phase cable retaining bolts (4).
15. Remove the 3 phase cables and housing (3).
16. Finish removal of the transmission while allowing the 3 phase cables to remain in the vehicle. Refer to «Transmission Replacement»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle__transmission-replacement) .
17. Remove the 3 phase cables from the vehicle.

Installation Procedure

1. Position the 3 phase cables in the vehicle.
2. Begin installation of the transmission. Refer to «Transmission Replacement»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle__transmission-replacement) .
3. Install a new 3 phase cable housing seal (2).
4. Install the 3 phase cables and housing (3).
5. Install the 3 phase cable retaining bolts (4). Tighten Tighten the bolts to 12 N.m (106 lb in).
6. Install the 3 phase cable bolt protective cover (5).
7. Install a new 3 phase cable cover seal (6).
8. Reconnect the 3 phase cable cover connector.
9. Install the 3 phase cable cover (7).
10. Install the transmission cover terminal housing (8).
11. Install the 3 phase cable cover bolts (9). Tighten Tighten the bolts to 12 N.m (106 lb in).
12. Install the 3 phase cable bracket bolts (1). Tighten Tighten the bolts to 12 N.m (106 lb in).
13. Complete installation of the transmission. Refer to «Transmission Replacement»(/gmc/sierra-2500/2012-2012/remont/automatic-trans/#automatic-transmission-2ml70-repair-instructions-on-vehicle__transmission-replacement) .
14. Lower the vehicle.
15. Install the 3 phase cable retainer (1) to the bracket.
16. Install the 3 phase cable retainer nut (2). Tighten Tighten the nut to 9 N.m (80 lb in).
17. Install the PIM 3 phase cables (3, 5) into the PIM distribution box with new seals (6).
18. Install the PIM 3 phase cable mounting fasteners (2, 4). Tighten Tighten the mounting fastener to 9 N.m (80 lb in).
19. Install the PIM 3 phase cable terminal fasteners (1). Tighten Tighten the terminal fastener to 9 N.m (80 lb in).
20. Install a new seal (3) on the PIM distribution box.
21. Position the terminal cover (2) onto the PIM distribution box ensuring the seal remains in place.
22. Tighten the terminal cover fasteners (1). Tighten Tighten the fasteners to 9 N.m (80 lb in).
23. Perform the high voltage enabling. Refer to «High Voltage Enabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-enabling) .

1. Remove the fender brace. Refer to «Front Fender Rear Upper Brace Replacement»(/gmc/sierra-2500/2012-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
2. Loosen the sight shield mounting fastener (1) and lift the sight shield from the ball studs (2).
3. Perform the High Voltage Disabling procedure. Refer to «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) .

1. Install the sight shield onto the ball studs (2) and tighten the sight shield mounting fastener (1). Tighten the fastener to 5 N.m (44 lb in).
2. Install the fender brace. Refer to «Front Fender Rear Upper Brace Replacement»(/gmc/sierra-2500/2012-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Enable high voltage. Refer to «High Voltage Enabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-enabling) .

1. Perform the High Voltage Disabling procedure. Refer to «High Voltage Disabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-disabling) .
2. Remove the air cleaner. Refer to «Air Cleaner Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-repair-instructions) .
3. Disconnect the drive motor generator control module assembly connector (1).
4. Drain the power electronics cooling system. Refer to «Generator Control Module Cooling System Draining and Filling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system__generator-control-module-cooling-system-draining) .
5. Remove the drive motor generator power inverter control module (PIM) 3 phase cable terminal fasteners (1).
6. Remove the PIM 3 phase cable mounting fasteners (2, 4).
7. Remove the PIM 3 phase cables (3, 5) from the PIM distribution box.
8. Remove and discard the seals (6).
9. Remove the HV dc electric air conditioning compressor module (ACCM) cable terminal fasteners (1).
10. Remove the HV dc electric ACCM cable mounting fasteners (3).
11. Remove the HV dc electric ACCM cable (4) from the PIM distribution box.
12. Remove the HV dc battery cable terminal fasteners (2).
13. Remove the HV dc battery cable mounting fasteners (5).
14. Remove the HV dc battery cable (6) from the PIM distribution box.
15. Inspect and retain the seals (7).
16. Remove the drive motor generator position sensor shield circuit fastener (2).
17. Remove the shield circuit harness (1).
18. Remove the PIM cooling inlet (4) and outlet (5) hoses.
19. Cap the coolant pipes (3, 6) to prevent coolant spillage when lifting the drive motor generator control module assembly from the vehicle.
20. Disconnect the APM assembly connector (2) using the following procedure: Push the green tab. Squeeze the gray side tabs, then rotate the lever.
21. Disconnect the APM assembly connector (3) using the following procedure: Remove the locking tab. Insert a small flat blade screwdriver into the locking tab area and raise the tab while pulling on the connector.
22. Disconnect the remaining APM assembly connector (1).
23. Remove the sight shield circuit breaker fasteners (1).
24. Remove the sight shield circuit breaker (2).
25. Remove the APM ground strap fastener (2) and ground strap (1).
26. Remove the drive motor generator control module assembly mounting fasteners (3) and retainers (4).
27. Remove the ball studs (1) from the drive motor generator control module.
28. Attach a lifting device (2 and 3) to the drive motor generator control module assembly at the three identified locations.
29. Lift the drive motor generator control module assembly from the vehicle.
30. To replace the drive motor generator power inverter module (PIM) assembly, refer to «Drive Motor Generator Power Inverter Module Removal and Installation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__drive-motor-generator-power-inverter-module) . To replace the accessory DC power control module, refer to «Accessory DC Power Control Module Removal and Installation»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system__accessory-dc-power-control-module-removal) .

1. Attach a lifting device (2 and 3) to the drive motor generator control module assembly at the three identified locations.
2. Lift the drive motor generator control module assembly into the vehicle.
3. Remove the lifting device and install the ball studs (1). Tighten the ball studs to 10 N.m (89 lb in).
4. Install the drive motor generator control module assembly retainers (4) and mounting nuts (3). Tighten the mounting nuts to 9 N.m (80 lb in).
5. Install the APM ground strap (1) and APM ground strap nut (2). Tighten the nut to 9 N.m (80 lb in).
6. Install the sight shield circuit breaker (2) and secure with bolts (1). Tighten the bolts to 5 N.m (44 lb in).
7. Connect the APM assembly connectors (1 and 3) and install any removed locking tabs.
8. Connect the APM assembly connector (2) using the following procedure: Push the lever up. NOTE: Install the connector (2) without disturbing the position of the lever. DO NOT use the lever to install the connector in place. Install the connector (2) onto the terminals by pushing on the connector only. Rotate the lever after the terminals are engaged. Push the green tab to lock the lever.
9. Remove the caps (3, 6) from the drive motor generator power inverter coolant pipes.
10. Connect the drive motor generator power inverter module (PIM) cooling inlet and outlet hoses (4, 5).
11. Install the shield circuit harness (1) and terminal fastener (2). Tighten the terminal fastener to 9 N.m (80 lb in).
12. Install the PIM 3 phase cables (3, 5) into the PIM distribution box with new seals (6).
13. Install the PIM 3 phase cable mounting fasteners (2, 4). Tighten the mounting fastener to 9 N.m (80 lb in).
14. Install the PIM 3 phase cable terminal fasteners (1). Tighten the terminal fastener to 9 N.m (80 lb in).
15. Install the HV dc battery cable (6) with seal (7) into the PIM distribution box.
16. Install the HV dc battery cable mounting fasteners (5). Tighten the mounting fastener to 9 N.m (80 lb in).
17. Install the high voltage (HV) dc battery cable terminal fasteners (2). Tighten the terminal fastener to 9 N.m (80 lb in).
18. Install the HV dc electric air conditioning compressor module (ACCM) cable (4) with seal (7) into the PIM distribution box.
19. Install the HV dc electric ACCM cable mounting fasteners (3). Tighten the mounting fasteners to 9 N.m (80 lb in).
20. Install the HV dc electric ACCM cable terminal fasteners (1). Tighten the terminal fastener to 9 N.m (80 lb in).
21. Install a new seal (3) on the PIM distribution box.
22. Clean the sealing surface of the 3 phase cable cover as necessary.
23. Position the 3 phase cable cover (2) onto the PIM distribution box ensuring the seal remains in place.
24. Tighten the 3 phase cable cover fasteners (1). Tighten the fasteners to 9 N.m (80 lb in).
25. Connect the drive motor generator control module assembly connector (1).
26. Fill the power electronics cooling system and test for leaks at all serviced connections. Refer to «Generator Control Module Cooling System Draining and Filling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-cooling-system__generator-control-module-cooling-system-draining) .
27. Install the sight shield. Refer to «Drive Motor Generator Control Module Sight Shield Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
28. Install the fender cross brace. Refer to «Front Fender Rear Upper Brace Replacement»(/gmc/sierra-2500/2012-2012/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
29. Perform the High Voltage Enabling procedure. Refer to «High Voltage Enabling»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-energy-storage-system__high-voltage-enabling) .
30. Install the air cleaner. Refer to «Air Cleaner Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/testing-diagnostics/#engine-controlsfuel-hybrid-hp2-60l-lz1-repair-instructions) .
31. For control module programming and setup procedures, refer to «Control Module References»(/gmc/sierra-2500/2012-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) .

Drive Motor Generator Power Inverter Module Removal and Installation

Special Tools

1. GE-48494 Power Electronics Pressure Test Adapter Kit
2. J 24460-01 Cooling System Pressure Tester

1. Remove the drive motor generator control module from the vehicle. Refer to «Drive Motor Generator Control Module Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Remove the temporary coolant pipe caps (1).
3. Drain the drive motor generator control module assembly of residual coolant by applying 30 psi regulated compressed air to the coolant inlet pipe until no coolant remains.
4. Remove the drive motor generator power inverter control module cover fasteners (1).
5. Remove the power inverter module cover (2). Discard the cover seal (3).
6. Remove the high voltage dc accessory DC power control module terminal fasteners (1) utilizing a magnetic socket.
7. Temporarily install the power inverter module cover (2) with 4 finger-tightened fasteners (1).
8. Rotate the drive motor generator control module assembly onto the power inverter module cover.
9. Remove the accessory DC power control module to power inverter module mounting fasteners (1).
10. Remove the accessory DC power control module (2) and discard the coolant seal (3).
11. Remove the drive motor generator power inverter coolant pipes: Remove the drive motor generator power inverter coolant pipe bolts (4, 7). Remove the drive motor generator power inverter coolant pipes (5, 8). Remove and discard coolant seals (6, 9).

1. Install new accessory DC power control module coolant seal (3).
2. Position the accessory DC power control module (2) onto the power inverter module ensuring the seals remain in place.
3. Install the accessory DC power control module mounting fasteners (1). Tighten the mounting fasteners to 10 N.m (89 lb in).
4. Install the drive motor generator power inverter coolant pipes unless a service replacement power inverter module is being installed: Lubricate the new seals (6, 9) with pre-mixed DEX-COOL®. Install new seals (6, 9) onto the drive motor generator power inverter coolant pipes (5, 8). Install the coolant pipes (5, 8) to the power inverter module assembly with bolts (4, 7). Tighten the fasteners to 5 N.m (44 lb in).
5. Rotate the drive motor generator control module assembly onto the accessory DC power control module.
6. Clamp GE-48494 adapter kit components (2, 3) to a coolant pipe.
7. Plug the remaining coolant pipe with the GE-48494 adapter kit plug and clamp (1).
8. Apply 20 psi (138 kPa) pressure with J 24460-01 pressure tester (4).
9. Monitor the pressure tester gauge for 5 minutes and ensure that pressure remains at the specified value. If the specified pressure cannot be maintained, disassemble the drive motor generator control module assembly and replace the coolant seal. If pressure remains at the specified value, proceed to the next step.
10. Remove all GE-48494 adapter kit components.
11. Remove the power inverter module cover retaining bolts (1).
12. Remove the power inverter module cover (2).
13. Install the high voltage dc accessory DC power control module terminal fasteners (1) utilizing a magnetic socket. Tighten the terminal fasteners to 9 N.m (80 lb in).
14. Install a new power inverter module cover seal (3).
15. Clean the sealing surface of the power inverter module cover as necessary.
16. Position the power inverter module cover (2) onto the power inverter module ensuring the seal remains in place.
17. Install the power inverter module cover fasteners (1). Tighten the fasteners to 5 N.m (44 lb in).
18. Install the drive motor generator control module. Refer to «Drive Motor Generator Control Module Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .

Accessory DC Power Control Module Removal and Installation

Special Tools

1. J 24460-01 Cooling System Pressure Tester
2. GE-48494 Power Electronics Pressure Test Adapter Kit

1. Remove the drive motor generator control module from the vehicle. Refer to «Drive Motor Generator Control Module Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .
2. Remove the accessory DC power control module ground strap bolt (1) and ground strap (2).
3. Remove the temporary coolant pipe caps (1).
4. Drain the drive motor generator control module assembly of residual coolant by applying 30 psi regulated compressed air to the coolant inlet pipe until no coolant remains.
5. Remove the drive motor generator power inverter control module cover fasteners (1).
6. Remove the power inverter module cover (2). Discard the cover seal (3).
7. Remove the high voltage dc accessory DC power control module terminal fasteners (1) utilizing a magnetic socket.
8. Temporarily install the power inverter module cover (2) with 4 finger-tightened fasteners (1).
9. Rotate the drive motor generator control module assembly onto the power inverter module cover.
10. Remove the accessory DC power control module to power inverter module mounting fasteners (1).
11. Remove the accessory DC power control module (2) and discard the coolant seal (3).

1. Install new accessory DC power control module coolant seal (3).
2. Position the accessory DC power control module (2) onto the power inverter module ensuring the seals remain in place.
3. Install the accessory DC power control module mounting fasteners (1). Tighten the mounting fasteners to 10 N.m (89 lb in).
4. Rotate the drive motor generator control module assembly onto the accessory DC power control module.
5. Clamp GE-48494 adapter kit components (2, 3) to a coolant pipe.
6. Plug the remaining coolant pipe with GE-48494 adapter kit plug and clamp (1).
7. Apply 20 psi (138 kPa) pressure with J 24460-01 pressure tester (4).
8. Monitor the pressure tester gauge for 5 minutes and ensure that pressure remains at the specified value. If the specified pressure cannot be maintained, disassemble the drive motor generator control module assembly and replace the coolant seals. If pressure remains at the specified value, proceed to the next step.
9. Remove all GE-48494 adapter kit components.
10. Remove the power inverter module cover retaining bolts (1).
11. Remove the power inverter module cover (2).
12. Install the high voltage dc accessory DC power control module terminal fasteners (1) utilizing a magnetic socket. Tighten the terminal fasteners to 9 N.m (80 lb in).
13. Install a new power inverter module cover seal (3).
14. Clean the sealing surface of the power inverter module cover as necessary.
15. Position the power inverter module cover (2) onto the power inverter module ensuring the seal remains in place.
16. Install the power inverter module cover fasteners (1). Tighten the fasteners to 5 N.m (44 lb in).
17. Install the ground strap (2) and bolt (1). Tighten the bolt to 22 N.m (16 lb ft).
18. Install the drive motor generator control module. Refer to «Drive Motor Generator Control Module Assembly Replacement»(/gmc/sierra-2500/2012-2012/remont/body-electrical/#hybridev-control-system) .

Overview

The drive motor generator power inverter module assembly converts high voltage direct current (DC) electrical energy to 3 phase alternating current (AC) electrical energy. The accessory DC power control module converts high voltage DC electric energy into low voltage (14V) and intermediate voltage (42V) in order to charge the vehicles accessory battery and supply electric energy to the 42V power steering system. The accessory DC power control module and power inverter module are fastened together and are referred to as the drive motor generator control module assembly. The drive motor generator control module assembly is cooled with pre-mixed Dexcool® circulating through a cooling system that is separate from the engine cooling system. The hybrid cooling system utilizes a heat exchanger at the front of the vehicle and electric pumps to circulate the coolant. The engine control module (ECM) monitors a temperature sensor in the hybrid cooling system and operates the radiator fan and the hybrid coolant pumps in response to system temperature.

High Voltage Circuits

Direct Current (DC)

The drive motor generator control module assembly is connected to each pole of the high voltage, direct current (DC) drive motor generator battery. Both of the negative and positive high voltage DC battery poles are isolated from the vehicle chassis by a specific amount of resistance. Each high voltage DC cable is switched ON or OFF by a high voltage, high current contactor relay contained within the drive motor generator battery assembly. All high voltage DC negative and positive DC cables are individually shielded and orange in color to alert the technician to the potential presence of high voltage. The electric air conditioning compressor module high voltage DC cables are externally connected at the drive motor generator control module assembly. The accessory DC power control module and power inverter module share an internal connection that supplies the accessory DC power control module with high voltage DC current.

Three Phase Alternating Current (AC)

Three cables connect each motor generator to the power inverter module. Each individually shielded cable is orange in color to alert the technician to the potential presence of high voltage.

Intermediate and Low Voltage Circuits

The accessory DC power control module converts high voltage 300V DC current into both intermediate voltage, 12v and low voltage, 12v current.

Intermediate Voltage 42V Direct Current

Intermediate voltage 42V cables are individually shielded and are blue in color to alert the technician to the potential presence of intermediate voltage.

Low Voltage 12v Direct Current

Low voltage 12v cables on the hybrid-electric vehicle do not require unique coloring or servicing procedures.

Drive Motor Generator Power Inverter Module Assembly

Overview

Contained within the power inverter module assembly are the hybrid powertrain control module, and two motor control modules. Each motor control module controls its respective motor generator. All three modules are flash-programmable micro-processors.

Hybrid Powertrain Control Module

Location

The hybrid powertrain control module is a non-serviceable, flash-programmable micro-processor contained within the power inverter module assembly.

Operating Functions

The hybrid powertrain control module is the main controller of hybrid operation. The hybrid powertrain control module determines when to perform hybrid operation modes such as engine Auto-stop and regenerative braking. The hybrid powertrain control module also operates in conjunction with the battery energy control module to determine when to enable and disable the DC high voltage circuits. Each motor control module operates the applicable electric motor generator based upon hybrid powertrain control module commands.

Communication and Hosted Diagnostics

The hybrid powertrain control module is the host controller for diagnostic trouble code (DTC) information for the following control modules

1. Accessory DC power control module
2. Battery energy control module
3. Motor control module 1
4. Motor control module 2
5. Auxiliary transmission fluid pump control module

These modules diagnose their own operation and determine when a fault condition is present. Diagnostic status is communicated to the hybrid powertrain control module through the following circuits

1. accessory DC power control module utilizes the GM Hi-speed, Hybrid LAN communication circuit
2. Battery energy control module utilizes the GM Hi-speed, Hybrid LAN communication circuit
3. Each motor control module and the hybrid powertrain control module exchange information and commands on the SPI bus internal communication circuit as well as the hi-speed hybrid GMLAN communication circuit.
4. Auxiliary transmission fluid pump control module utilizes a dedicated diagnostic status circuit

In the event a hosted module communicates a fault condition, the hybrid powertrain control module will determine if hybrid operation is effected and notify the vehicle operator by requesting the MIL illuminate and/or by displaying a hybrid service required message. In addition, the hybrid powertrain control module will store the associated DTC information for retrieval by a scan tool. Some hosted modules may require an ignition cycle to clear certain DTCs from the hybrid powertrain control module.

Circuit Inputs

In addition to GMLAN parameters, the hybrid powertrain control module directly monitors the following signal circuits

1. Transmission shift selector internal mode switch (IMS) Direction and Park/Neutral switch signals
2. Engine crankshaft position (CKP) sensor signal
3. Auxiliary transmission fluid pump diagnostic circuit
4. High voltage interlock circuit (HVIC)

Circuit Outputs

In addition to GMLAN and SPI bus commands, the hybrid powertrain control module directly controls the following output circuits

1. Auxiliary transmission fluid pump control circuit
2. Battery energy control module high voltage contactor relay pulse width modulated (PWM) control circuit

Motor Control Module 1 and 2

Location

Each electric motor generator located within the transmission assembly is controlled by its own motor control module flash-programmable, micro-processor. Each motor control module is contained within the power inverter module. Also contained within the power inverter module is the hybrid powertrain control module micro-processor.

Operating Functions

Each motor control module operates the applicable electric motor generator based upon hybrid powertrain control module commands. Each motor control module controls the speed, direction and output torque of its respective traction motor through the sequencing actuation of high current switching transistors called insulated gate bipolar transistors (IGBTs).

Communication and Hosted Diagnostics

In addition to the internal SPI bus communication circuit between the hybrid powertrain control module and each motor control module, the motor control modules also communicate on the Hi-speed and Hybrid GMLAN communication circuits. The motor control module does not store its own diagnostic trouble code (DTC) information. The hybrid powertrain control module will store motor control module associated DTC information for retrieval by a scan tool. The scan tool can communicate directly with each motor control module in order to retrieve data parameters only.

Circuit Inputs

In addition to GMLAN parameters, each motor control module monitors its respective motor generator for voltage, current, speed, direction and temperature. Additionally, the motor control module monitors the IGBT components for temperature and proper operation. Some of the motor control module operation data is shared with the hybrid powertrain control module.

Circuit Outputs

Each motor control module controls its respective IGBT driver board that in-turn controls each motor generator. The motor generators operate using three-phase alternating current (AC) electricity. Three cables connect each motor generator to the power inverter module. Each individually shielded cable is orange in color to alert the technician that the potential for high voltage is present.

Accessory DC Power Control Module

Location

The accessory DC power control module is affixed to and located underneath the power inverter module. It is fastened to the power inverter module with external mounting fasteners and 2 internal high voltage circuit connection fasteners. The accessory DC power control module shares a coolant passage with the power inverter module and as such is gasketed to the power inverter module.

Operating Functions

The accessory DC power control module is the device which converts high voltage (300V) direct current (DC) to low voltage 12v DC for accessory electrical operation and to charge the 12 volt accessory battery. The accessory DC power control module also converts high voltage DC to intermediate (42V) DC to supply the electric power steering system with voltage. The accessory DC power control module is capable of supplying up to 175 Amps of 12 volt DC and up to 50 Amps of 42 volt DC. In Jump Assist mode the accessory DC power control module converts 12 volt DC to high voltage DC to charge the high voltage hybrid batteries. The accessory DC power control module is capable of supplying up to 2.7 Amps at 290 volts DC on the high voltage circuit when operating in Jump Assist. An external 12V DC battery charger is required during the Jump Assist mode because the accessory DC power control module and vehicle controllers may draw as much as 80 Amps of current from the vehicles 12 volt DC system.

Communication and Hosted Diagnostics

The accessory DC power control module has internal diagnostic tests that run at both power-up and during operation. All DTCs from the accessory DC power control module are reported to and hosted by the hybrid powertrain control module. The accessory DC power control module communicates directly only with the hybrid powertrain control module and only on the high speed hybrid GMLAN communication circuit.

Circuit Inputs

Inputs supported by the accessory DC power control module include the high voltage and 12 volt circuits. The accessory DC power control module also monitors various internal components for current, voltage and temperature. The accessory DC power control module is also connected to the high speed hybrid GMLAN communication circuit. An individual 12 volt discrete circuit powers ON the accessory DC power control module. The accessory DC power control module will not begin conversion of voltage however, until the appropriate GMLAN enable signal is communicated to it by the hybrid powertrain control module.

Circuit Outputs

The only outputs supported by the accessory DC power control module are the 12 volt and 42 volt conversion during normal vehicle operation and high voltage conversion during Jump Assist.

Electromagnetic Compatibility (EMC)

Overview

Vehicles are typically subject to certain legal requirements that limit the amount of electromagnetic interference (EMI) that can be generated by the vehicles electronic devices. Additionally, the electronic devices within the vehicle must be able to withstand a certain amount of EMI without effecting their operation. EMI is generated whenever electrical current flows through a circuit. The amount of EMI generated, or amplitude, is usually dependant upon the amount of current flow, amperage, and the on-off pattern of current flow through the circuit, frequency. The EMI requirements are generally referred to as electromagnetic compatibility (EMC).

There are many ways of ensuring the vehicle meets EMC requirements. These include

1. Adding capacitors and resistors to certain electrical circuits
2. Regulating the frequency at which a component may operate
3. Shielding the wires, cables and components

Circuit Design

The drive motor generator power inverter module and the accessory DC power control module assembly each contain filter capacitors connected to the high voltage circuits. These capacitors are necessary to reduce the voltage spikes that occur as a result of the switching of current On and Off. Reducing voltage spikes reduces EMI. The frequency of current switching is also closely regulated. Too high a frequency can cause an increase in EMI generation.

Wiring/Cable Design

Different types of wire/cable shielding methods are utilized in the vehicle. Common types of circuit shielding include twisted-pair and internal braid or foil. Twisted pair is typically used in circuits such as high speed GMLAN communication circuits. The wire pair is twisted together at a particular turns-per-length ratio. Shielded cable is utilized for all other circuits requiring either protection from external EMI or to reduce EMI radiation of the cable itself into other nearby components or circuits.

High Voltage Cable

1. Battery Positive and Negative 300V Cable Assembly
2. Drive Motor Generator Power Inverter Module 3 Phase Cable Assembly
3. Air Conditioning Compressor Module Assembly

The high voltage cables utilize internal braid shielding. Typically, both ends of the internal braid shield are attached to chassis ground. All of the high voltage, internally shielded cables are grounded at their cable end attachment points. Mounting blocks, where used, perform the shield to chassis ground connection. Connection points not serviced with a mounting block utilize a separate ring terminal.

Low and Intermediate Voltage Wiring

The signal circuits for the transmission sensors utilize shielding protection. The drive motor generator position sensor and temperature sensor circuits utilize internal foil shielding. The wiring harness external of the transmission assembly is connected to chassis ground with ring terminals at the drive motor control module assembly. The internal transmission wiring harness is attached to chassis ground with a ring terminal at the valve body assembly.

The auxiliary transmission fluid pump 3 phase cables utilize internal foil shielding. The wiring harness shield is connected to chassis ground within the auxiliary transmission fluid pump control module.

The power steering intermediate voltage wiring utilizes internal foil shielding. The wiring harness shield is connected to chassis ground at the accessory DC power control module connector and within the power steering motor assembly.

Component Shielding

Certain components utilize their structure to effectively shield EMI. Metal covers, chassis grounded metal cases and electro-magnetically conductive gaskets may all be part of a components EMC design.

Shielding Loss

A loss of proper shielding may result in poor AM band radio reception and/or incorrect sensor circuit readings depending upon the location of the shield loss. High voltage cables are not repairable. No attempt should ever be made to repair any portion of high voltage cables. Certain Low and Intermediate voltage shielded wiring harnesses may be repairable. Refer to Wiring Repairs .

High Voltage Monitoring Systems Description

The hybrid system monitors several high voltage components for attempted access. Additionally, a minimum amount of isolation resistance is maintained at all times between both negative and positive poles of the hybrid battery and the vehicle chassis. The drive motor generator power inverter module microprocessors and the battery energy control module monitor the hybrid system for access and loss of isolation detection.

High Voltage Interlock Circuit (HVIC)

The HVIC is a wire loop that passes through certain high voltage components. The HVIC is used to determine if access to high voltage components is being attempted. The opening of these high voltage components causes the HVIC to open. The hybrid system may react to the loss of HVIC continuity by opening the high voltage contactor relays and discharging the high voltage capacitors. The HVIC signal is generated by the battery energy control module. The HVIC status is monitored by each motor control module as well as the hybrid powertrain control module and the battery energy control module.

High Voltage DC Chassis Isolation

The hybrid system monitors the electrical potential between high voltage and the vehicle chassis. High voltage should always be isolated from the vehicle chassis by a certain amount of resistance to avoid the potential for a life threatening current path. In the event that a high voltage leak path is detected to the vehicle chassis, the hybrid system will set a diagnostic trouble code (DTC). High voltage DC chassis isolation is monitored by both the motor control modules and the battery energy control module.

Testing for isolation requires special tools and procedures. Because of the high voltages present in the hybrid system, a loss of isolation may occur due to insulation breakdown. Insulation breakdown typically occurs only when high voltages and/or current is present. Conditions such as insulation breakdown cannot be diagnosed with a typical DMM because high voltage is not used by the DMM when measuring resistance.

Hybrid Modes of Operation Description

This overview is not a comprehensive list of all aspects of the Two-Mode Hybrid vehicle. Refer to Automatic Transmission 2ML70 Electronic Component Description for information regarding transmission operation. More detailed and comprehensive information is also available through the dealer training program.

Engine Starting

This vehicle does not use a 12 V starter motor to crank the internal combustion engine. A much more powerful 300 V motor/generator located within the transmission is utilized to crank the engine. The 300 V drive motor generator can rotate the engine to operating speed (800 RPM) within just a few hundred milliseconds. The 300 V drive motor generator allows near-instant starting of the engine. Once started, engine operation may cycle between Autostop (engine off) and Autostart (engine running) for the duration of the drive trip.

Autostop

After a successful engine start, the hybrid powertrain control module may turn off the engine and operate in the Autostop mode. Some of the vehicle conditions that allow the engine to stop running and enter the Autostop mode include

1. Vehicle power mode is correct: The ignition switch is in the Run position after first being turned to the crank position which resulted in a successful engine start, OR The ignition switch is turned to the Run position after a successful remote vehicle start request.
2. Hood switch position status is Closed.
3. ECM is not requesting continued engine operation for diagnostic purposes.
4. Gear selector is not in the Reverse or Manual position.
5. Hybrid battery state of charge is more than 20 percent.
6. Hybrid battery voltage, temperature or power limits are not exceeded.
7. Engine coolant temperature (ECT) is more than an acceptable limit.
8. Drive motor generator temperature limits are not exceeded.
9. Drive motor generator power inverter module temperature limits are not exceeded.
10. No hybrid system faults exist.

A chime will sound if the drivers door is opened while in Autostop as a reminder that the engine is not in the OFF mode.

Engine OFF and AUTOSTOP modes are indicated on the tachometer display.

1. When the tachometer needle indicates OFF, the engine is not running and will remain Off until the ignition key is placed in the Crank position or a remote vehicle start request is received from the keyless entry transmitter.
2. When the tachometer needle indicates AUTOSTOP, the engine is not running but may Autostart at any time without notice.

Autostart

The Two-Mode Hybrid vehicle does not require internal combustion engine operation at all times. After a successful engine start, the hybrid powertrain control module may turn off the engine (Autostop) when not required for the current vehicle conditions. The engine will remain off while in Autostop mode, until such time that vehicle conditions require the engine to run. The near-instant starting of the engine from Autostop mode is called Autostart. Some of the vehicle conditions that may cause the hybrid powertrain control module to exit the Autostop mode and Autostart the engine include

1. Hood switch position status changes to Open
2. ECM Request
3. Gear selector is placed in the Reverse or Manual position
4. Hybrid battery state of charge is too low
5. Hybrid battery voltage, temperature or power limits are exceeded
6. Engine coolant temperature (ECT) is too low
7. Drive motor generator temperature limits are exceeded
8. Drive motor generator power inverter module temperature limits are exceeded
9. A hybrid system fault is observed
10. Electric Launch capability has been exceeded and engine operation is required

Electric Launch/Assist

The transmission assembly contains two 300 V drive motor generator assemblies. These powerful 60 kW drive motor generators are capable of propelling the vehicle while the engine is in the Autostop mode or they may assist an already running engine. Depending upon accelerator pedal position, the vehicle may be propelled solely with the electric drive motor generators at speeds exceeding 41 km/H (26 mph) before assistance from the engine is required. The engine will Autostart when driving conditions require engine assistance. During engine running conditions, the torque provided by the drive motor generators is supplemented with the engine torque output.

Regenerative Braking

When the vehicle is coasting or braking the hybrid powertrain control module may operate the drive motor generators in an electrical generation mode. Operating as electrical generators, the drive motor generators exert a driveline load that helps to slow the vehicle. The electrical energy that the drive motor generators create is transferred by the drive motor generator power inverter module to the drive motor generator battery assembly (hybrid batteries). Constant communication between the hybrid powertrain control module and the electronic brake control module (EBCM) allows the blending of regenerative braking force with hydraulic braking force.

Enhancements to Engine Operation

While not unique to the Two-Mode hybrid vehicle, the following modes of operation benefit from expanded operational ranges. Expanded operational range is possible because the drive motor generators can be utilized to smooth driveline disturbances that would be objectionable without the intervention of the drive motor generator.

Deceleration Mode

When the driver releases the accelerator pedal, air flow into the engine is reduced. The ECM monitors the corresponding changes in the TP, the MAP, and the MAF. The ECM shuts OFF fuel completely if the deceleration is very rapid, or for long periods, such as long, closed-throttle coast-down. The fuel shuts OFF in order to prevent damage to the catalytic converters. This mode is activated more quickly and for a longer duration in the Two-Mode hybrid vehicle.

Cylinder Deactivation (Active Fuel Management)

To provide maximum fuel economy under light load driving conditions, the engine control module (ECM) will command the cylinder deactivation system ON to deactivate engine cylinders 1 and 7 on the left bank, and cylinders 4 and 6 on the right bank, switching to a V4 mode. The engine will operate on 8 cylinders, or V8 mode, during engine starting, engine idling, and medium to heavy throttle applications. This mode is activated more quickly and for a longer duration in the Two-Mode hybrid vehicle.

Special Tools

Illustration Tool Number/ Description DT-47825-10 Jumper Harness DT-48493 Jumper Harness EL-48458 Pre-Charge Tester EL-48900 HEV Safety Kit GE-48494 Power Electronics Pressure Test Adapter Kit J 24460-01 Cooling System Pressure Tester J 38522 Variable Signal Generator

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Diagnostic Repair Verification
• Control Module References
• Data Communication Schematics
• WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Drive Motor Battery Replacement and Shipping Preparation
• Diagnostic Trouble Code (DTC) List - Vehicle
• Battery Negative Cable Disconnection and Connection
• Transmission Control Wiring Harness Extension Harness Removal
• Electronic Component Description
• Symptoms - Engine Cooling
• Automatic Transmission Overheating
• WIRING SYSTEMS AND POWER MANAGEMENT - INLINE HARNESS CONNECTOR END VIEWS - INDEX
• High Voltage Disabling
• Engine Cranks But Does Not Run
• Hybrid Cooling System Loss of Coolant
• Engine Overheating
• Hybrid Cooling System Overheating (Electrical)
• Hybrid Cooling System Leak Test
• 200 Amp Mega Fuse and Auxiliary Electrical Center 12VDC Junction Block Replacement
• Generator Control Module Cooling System Draining and Filling
• Symptoms - Engine Mechanical
• DTC B1433
• DTC P0335
• Manual Shift Shaft Position Switch Replacement
• Power Steering Assist Motor Replacement
• Engine Controls Schematics
• DTC P1AE6 or P1AE7
• Drive Motor Generator Battery Control Module Scan Tool Information
• Air Conditioning Compressor Replacement (LU3)
• Air Conditioning Compressor Replacement (LZ1, L20, LC9, L9H, L92, LMG)
• Air Conditioning Compressor Replacement (LGH, LML)
• Transmission Fluid Level and Condition Check
• Line Pressure Check
• Accessory DC Power Control Module Scan Tool Information
• Transmission General Description
• Checking Aftermarket Accessories
• Range Selector Lever Cable Adjustment
• High Voltage Enabling
• Engine Shield Replacement
• Fastener Caution
• Transmission Replacement
• Front Fender Rear Upper Brace Replacement
• Air Cleaner Assembly Replacement
• DTC B008A or B008B
• Special Tools
• Temperature Versus Resistance
• Drive Motor Generator Power Inverter Module Removal and Installation
• Symptoms - Hybrid Controls
• High Voltage System Diagnosis (EL-48458)
• High Voltage Monitoring Systems Description
• Hybrid Modes of Operation Description
• Accessory DC Power Control Module Removal and Installation