FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

Part 2






P0ADD - Hybrid/EV Battery Negative Contactor Diagnosis

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


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

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

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


Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:


* Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.

* Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.


- Visually and functionally inspect the gloves before use.

- Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.


Failure to follow the procedures exactly as written may result in serious injury or death.


Danger: The Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.


1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Connect the 12 V battery.
3. Disconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.
4. Vehicle 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 ohm between the ground circuit terminal 5 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 9 and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the A4 hybrid/EV battery pack.

6. Reconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.

Note: If connectors X1 and X2 were disconnected during the disabling procedure, reconnect X1 before commanding the contactor closed.

7. Vehicle in Service Mode, command the Hybrid/EV Battery Negative Contactor CLOSED.

Note: Ignore DTC P0AD9, P0ADD, P0AE4, P0D0A, P0D11, P1EBC or P1EC3 when disconnecting the X1 connector with the Vehicle in Service Mode.

8. Disconnect the X1 harness connector at the A28 hybrid/EV battery contactor assembly.
9. Connect a test lamp between control circuit terminal 4 and ground.
10. Vehicle in Service Mode, command the Hybrid/EV Battery Negative Contactor OPEN and CLOSED with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the hybrid powertrain control module 2.
If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the hybrid powertrain control module 2.

11. If all circuits test normal, replace the A28 hybrid/EV battery contactor assembly.

P0AA1 or P0AD9 - Hybrid/EV Battery Positive Contactor Diagnosis

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


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

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

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


Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:


* Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.

* Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.


- Visually and functionally inspect the gloves before use.

- Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.


Failure to follow the procedures exactly as written may result in serious injury or death.


Danger: The Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.


1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Connect the 12 V battery.
3. Disconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.
4. Vehicle 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 ohm between the ground circuit terminal 5 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 9 and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the A4 hybrid/EV battery pack.

6. Reconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.

Note: If connectors X1 and X2 were disconnected during the disabling procedure, reconnect X1 before commanding the contactor closed.

7. Vehicle in Service Mode, command the Hybrid/EV Battery Positive Contactor CLOSED.

Note: Ignore DTC P0AD9, P0ADD, P0AE4, P0D0A, P0D11, P1EBC or P1EC3 when disconnecting the X1 connector with the Vehicle in Service Mode.

8. Disconnect the X1 harness connector at the A28 hybrid/EV battery contactor assembly.
9. Connect a test lamp between control circuit terminal 2 and ground.
10. Command the Hybrid/EV Battery Positive Contactor OPEN and CLOSED with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the hybrid powertrain control module 2.
If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the hybrid powertrain control module 2.

11. If all circuits test normal, replace the A28 hybrid/EV battery contactor assembly.

P1EBD - Battery Charging System Contactors Stuck Open Diagnosis

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


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

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

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


Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:


* Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.

* Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.


- Visually and functionally inspect the gloves before use.

- Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.


Failure to follow the procedures exactly as written may result in serious injury or death.


Danger: The Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.


1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Connect the 12 V battery.
3. Disconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.
4. Vehicle 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 ohm between the ground circuit terminal 5 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 9 and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the A4 hybrid/EV battery pack.

6. Reconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.

Note: If connectors X1 and X2 were disconnected during the disabling procedure, reconnect X1 before commanding the contactor closed.

7. Vehicle in Service Mode, command the Battery Charging System Negative Contactor CLOSED.

Note: Ignore DTC P0AD9, P0ADD, P0AE4, P0D0A, P0D11, P1EBC or P1EC3 when disconnecting the X1 connector with the Vehicle in Service Mode.

8. Disconnect the X1 harness connector at the A28 hybrid/EV battery contactor assembly.
9. Connect a test lamp between control circuit terminal 9 and ground.
10. Command the Battery Charging System Negative Contactor OPEN and CLOSED with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the hybrid powertrain control module 2.
If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the hybrid powertrain control module 2.

11. Connect a test lamp between control circuit terminal 7 and ground.
12. Command the Battery Charging System Positive Contactor OPEN and CLOSED with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the hybrid powertrain control module 2.
If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the hybrid powertrain control module 2.

13. If all circuits test normal, replace the A28 hybrid/EV battery contactor assembly.

P0D11 - Battery Charging System Negative Contactor Diagnosis

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


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

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

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


Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:


* Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.

* Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.


- Visually and functionally inspect the gloves before use.

- Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.


Failure to follow the procedures exactly as written may result in serious injury or death.


Danger: The Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.


1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Connect the 12 V battery.
3. Disconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.
4. Vehicle 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 ohm between the ground circuit terminal 5 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 9 and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the A4 hybrid/EV battery pack.

6. Reconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.

Note: If connectors X1 and X2 were disconnected during the disabling procedure, reconnect X1 before commanding the contactor closed.

7. Vehicle in Service Mode, command the Battery Charging System Negative Contactor CLOSED.

Note: Ignore DTC P0AD9, P0ADD, P0AE4, P0D0A, P0D11, P1EBC or P1EC3 when disconnecting the X1 connector with the Vehicle in Service Mode.

8. Disconnect the X1 harness connector at the A28 hybrid/EV battery contactor assembly.
9. Connect a test lamp between control circuit terminal 9 and ground.
10. Command the Battery Charging System Negative Contactor OPEN and CLOSED with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the hybrid powertrain control module 2.
If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the hybrid powertrain control module 2.

11. If all circuits test normal, replace the A28 hybrid/EV battery contactor assembly.

P0D0A - Battery Charging System Positive Contactor Diagnosis

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


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

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

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


Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:


* Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.

* Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.


- Visually and functionally inspect the gloves before use.

- Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.


Failure to follow the procedures exactly as written may result in serious injury or death.


Danger: The Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.


1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Connect the 12 V battery.
3. Disconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.
4. Vehicle 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 ohm between the ground circuit terminal 5 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 9 and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the A4 hybrid/EV battery pack.

6. Reconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.

Note: If connectors X1 and X2 were disconnected during the disabling procedure, reconnect X1 before commanding the contactor closed.

7. Vehicle in Service Mode, command the Battery Charging System Negative Contactor CLOSED.

Note: Ignore DTC P0AD9, P0ADD, P0AE4, P0D0A, P0D11, P1EBC or P1EC3 when disconnecting the X1 connector with the Vehicle in Service Mode.

8. Disconnect the X1 harness connector at the A28 hybrid/EV battery contactor assembly.
9. Connect a test lamp between control circuit terminal 7 and ground.
10. Command the Battery Charging System Positive Contactor OPEN and CLOSED with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the hybrid powertrain control module 2.
If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the hybrid powertrain control module 2.

11. If all circuits test normal, replace the A28 hybrid/EV battery contactor assembly.

P1EBC, P1EBE, or P1EBF - Hybrid/EV Battery Multifunction Contactor Diagnosis

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


The High Voltage Disabling procedure will perform the following tasks:


* Identify how to disable high voltage.

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

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


Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:


* Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.

* Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.


- Visually and functionally inspect the gloves before use.

- Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.


Failure to follow the procedures exactly as written may result in serious injury or death.


Danger: The Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.


1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Connect the 12 V battery.
3. Disconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.
4. Vehicle 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 ohm between the ground circuit terminal 5 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

5. Verify that a test lamp illuminates between the B+ circuit terminal 9 and ground.

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the A4 hybrid/EV battery pack.

6. Reconnect the X2 harness connector at the A28 hybrid/EV battery contactor assembly.

Note: If connectors X1 and X2 were disconnected during the disabling procedure, reconnect X1 before commanding the contactor closed.

7. Vehicle in Service Mode, command the Hybrid/EV Battery Multifunction Contactor CLOSED.

Note: Ignore DTC P0AD9, P0ADD, P0AE4, P0D0A, P0D11, P1EBC or P1EC3 when disconnecting the X1 connector with the Vehicle in Service Mode.

8. Disconnect the X1 harness connector at the A28 hybrid/EV battery contactor assembly.
9. Connect a test lamp between control circuit terminal 6 and ground.
10. Command the Hybrid/EV Battery Multifunction Contactor OPEN and CLOSED with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the hybrid powertrain control module 2.
If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the hybrid powertrain control module 2.

11. If all circuits test normal, replace the A28 hybrid/EV battery contactor assembly.

Repair Instructions

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

* Drive Motor Battery Wire Junction Block Relay Replacement Drive Motor Battery Wire Junction Block Relay Replacement
* Drive Motor Battery Replacement and Shipping Preparation Procedures
* Control Module References Programming and Relearning for hybrid/EV powertrain control module 2 replacement, programming and setup