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Home >> Chevrolet >> 2012 >> Volt L4-1.4L Elect >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P1BA2 >> Part 1

Part 1




DTC P0AA1, P0AD9, P0ADD, P0AE2, P0AE4, P0D0A, P0D11, P1EBC-P1EBF, P1EC0, or P1EC3-P1EC5

Diagnostic Instructions

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

DTC Descriptors
DTC P0AA1
- Hybrid/EV Battery Positive Contactor Circuit Stuck Closed

DTC P0AD9
- Hybrid/EV Battery Positive Contactor Control Circuit

DTC P0ADD
- Hybrid/EV Battery Negative Contactor Control Circuit

DTC P0AE2
- Hybrid/EV Battery Precharge Transistor Circuit Stuck On

DTC P0AE4
- Hybrid/EV Battery Precharge Transistor Control Circuit

DTC P0D0A
- Battery Charging System Positive Contactor Control Circuit

DTC P0D11
- Battery Charging System Negative Contactor Control Circuit

DTC P1EBC
- Hybrid/EV Battery Multifunction Contactor Control Circuit

DTC P1EBD
- Battery Charging System Contactors Stuck Open

DTC P1EBE
- Hybrid/EV Battery Multifunction Contactor Stuck Open

DTC P1EBF
- Hybrid/EV Battery Multifunction Contactor Stuck Closed

DTC P1EC0
- Hybrid/EV Battery System Contactors Stuck Open

DTC P1EC3
- Hybrid/EV Battery Pack Heater Transistor Control Circuit

DTC P1EC4
- Hybrid/EV Battery Pack Heater Transistor Stuck Off

DTC P1EC5
- Hybrid/EV Battery Pack Heater Transistor Stuck On

Circuit/System Description

The hybrid/EV battery contains 5 high voltage contactors and 2 transistors. The high voltage contactors and transistors allow the high voltage DC batteries to be connected to the vehicle or safely contain the high voltage DC within the hybrid/EV battery assembly. The 5 high voltage contactors consist of a main positive high voltage contactor, main negative high voltage contactor, charge positive high voltage contactor, charge negative high voltage contactor, and multi-function high voltage contactor. The 2 transistors consist of the precharge transistor and heater transistor. The contactors and transistors close and open in a specific sequence controlled by the hybrid/EV powertrain control module 2. The hybrid/EV powertrain control module 2 supplies voltage to the control circuit for the high voltage contactors/transistors. Ground is provided through the case ground.

Conditions for Running the DTC

P0AA1
* Is run once during a precharge event.
* The 12 V battery voltage is greater than 9 V.
* The main negative contactor is closed.
* The bus voltage reading at the hybrid/EV powertrain control module 2 is less than 15% of battery voltage before the negative contactor closes.
* None of the following DTCs are set; P0ABC, P0ABD, P1A07, P0ABB, P0AF8, P1AE8, P1AE9, or P1AEC

P0AD9, P0ADD, P0AE4, P0D0A, P0D11, and P1EBC

The 12 V battery voltage is greater than 10 V.

P0AE2
* During precharge mode.
* The multifunction contactor and negative contactor are closed.
* None of the following DTCs are set; P0AA1, P0ABC, P0ABD, P1A07, P0ABB, P0AF8, P1AE8, P1AE9, or P1AEC

P1EBD or P1EBE
* Runs once at the beginning of each charge cycle.
* The 12 V battery voltage is greater than 9 V.
* The vehicle is in charge mode.
* Charge mode is not in heat only mode.
* The heater transistor is commanded on for 2 seconds.
* None of the following DTCs are set; P0AC1, P0AC2, P0B10, P0B11, P0B13, P0D53, P0D54, P1EBA, or P1EBB.

P1EBF

CHARGE MODE

* Runs once during charger precharge.
* The 12 V battery voltage is greater than 9 V.
* The battery charger negative and positive contactors are closed.
* None of the following DTCs are set; P0AC1, P0AC2, P0B10, P0B11, P0B13, P0D53, P0D54, P1EBA, or P1EBB.
OR

BATTERY HEATING ONLY MODE

* The 12 V battery voltage is greater than 9 V.
* The battery charger is in heating only mode.
* Battery current is greater than 1 A.
* None of the following DTCs are set; P0AC1, P0AC2, P0B10, P0B11, P0B13, P0D53, P0D54, P1EBA, or P1EBB.

P1EC0
* The 12 V battery voltage is greater than 9 V.
* The main positive and negative contactors are closed for more than 1 second.
* None of the following DTCs are set; P1AE8, P1AE9, or P1AEC.

P1EC3
* The hybrid/EV powertrain control module is awake and communicating.
* The 12 V battery voltage is greater than 9 V.

P1EC4
* Runs once at the beginning of each charge cycle.
* The 12 V battery voltage is greater than 9 V.
* The vehicle is in charge mode.
* Charge mode is not in heat only mode.
* None of the following DTCs are set; P0AC1, P0AC2, P0B10, P0B11, P0B13, P0D53, P0D54, P1EBA, or P1EBB.

P1EC5
* The 12 V battery voltage is greater than 9 V.
* During battery charger precharge mode.
* The battery charger negative and positive contactors are closed.
* The multifunction contactor is open.
* The heater transistor duty cycle is less than 5 %.
* None of the following DTCs are set; P0D53 or P0D54.

Conditions for Setting the DTC

P0AA1 and P0AE2

The bus voltage is measured to be greater than 80% of battery voltage.

P0AD9, P0ADD, P0AE4, P0D0A, P0D11, and P1EBC

The hybrid/EV powertrain control module 2 has detected an open or short to voltage in the control circuit for the corresponding contactor.

P1EBD
* The heater transistor is commanded on for 2 seconds.
* The charger commanded output current is greater than 1 A and the charger output current is less than 1 A.

P1EBE

The Accumulated Battery Current greater than 100 A has been detected for 4 seconds.

P1EBF

CHARGE MODE

The charger high voltage output is greater than 130 V for the first 300 ms of the charger precharge mode.

OR

BATTERY HEATING ONLY MODE

Battery current of more than 1 A is detected at the charger during battery heater only mode.

P1EC0

The main bus voltage is less than 80% of battery voltage.

P1EC3

The hybrid/EV powertrain control module 2 has detected a fault in the heater transistor control circuit.

P1EC4

The total Accumulated Battery Current difference between the battery charger output current and the battery charging current after 4 seconds is less than 200 A.

P1EC5

The battery charger sensed current is greater than 0.4 A during the battery charger precharge mode with the multifunction and heater transistor commanded OFF.

Action Taken When the DTC Sets

* DTCs P0AA1, P0AD9, P0AE2, P0AE4, P0D0A, P0D11, P1EBD, P1EBE, P1EC0, or P1EC5 are type A DTCs.
* The contactors will be opened.
* Battery charging mode will not be available.
OR
* DTCs P0ADD, P1EBC or P1EBF, P1EC3, or P1EC4 are type B DTCs.
OR
* DTC P1EC3 is a type B DTC.
* The hybrid/EV battery heater will be disabled.

Conditions for Clearing the DTC

* DTCs P0AA1, P0AD9, P0AE2, P0AE4, P0D0A, P0D11, P1EBD, P1EBE, P1EC0, or P1EC5 are type A DTCs.
OR
* DTCs P0ADD, P1EBC or P1EBF, P1EC3, or P1EC4 are type B DTCs.

Diagnostic Aids

* P1EC5 may cause a overheat condition and set a P0C4A.
* P0ADD will result in precharge too long and set a P0C78.
* P1EC3 or P1EC4 will prevent battery heating and the vehicle will be unable to start in cold weather with battery temperatures below -25°C (-13°F).

Note: If the high voltage contactors opened while under high current load, replace the drive motor battery wire junction block relay. The following conditions could cause the high voltage contactors to open while under high current load:

* A collision resulting in supplemental inflatable restraint deployment.
* A loss of power or ground to the hybrid/EV powertrain control module 2 while the vehicle is moving.

Reference Information
Schematic Reference

Hybrid Energy Storage Schematics Hybrid Energy Storage Schematics
Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation

Drive Motor Battery System Description Drive Motor Battery System Description
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References Programming and Relearning for scan tool information
Special Tools

EL-48900 - HEV Safety Kit

EL-50211 - Low Voltage Jumper Harness Extension

For equivalent regional tools, refer to Special Tools Tools and Equipment.

Circuit/System Verification

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. Vehicle in Service Mode, verify that DTC P0AE2, P0AE4, P1EC3, P1EC4 or P1EC5 is not set.

• If DTC P0AE2 or P0AE4 is set, refer to Hybrid/EV Battery Precharge Transistor Diagnosis.
• If DTC P1EC3, P1EC4 or P1EC5 is set, refer to Hybrid/EV Battery Pack Heater Transistor Diagnosis.

4. Command the Hybrid/EV Battery Negative Contactor OPEN and CLOSED with a scan tool while listening for the contactor to open and close. The Hybrid/EV Battery Negative Contactor should be heard opening and closing.

• If the Hybrid/EV Battery Negative Contactor does not open and close, refer to Hybrid/EV Battery Negative Contactor Diagnosis.

5. Command the Hybrid/EV Battery Positive Contactor OPEN and CLOSED with a scan tool while listening for the contactor to open and close. The Hybrid/EV Battery Positive Contactor should be heard opening and closing.

• If the Hybrid/EV Battery Positive Contactor does not open and close, refer to Hybrid/EV Battery Positive Contactor Diagnosis.

6. Command the Battery Charging System Negative Contactor OPEN and CLOSED with a scan tool while listening for the contactor to open and close. The Battery Charging System Negative Contactor should be heard opening and closing.

• If the Hybrid/EV Battery Negative Contactor does not open and close, refer to Battery Charging System Negative Contactor Diagnosis.

7. Command the Battery Charging System Positive Contactor OPEN and CLOSED with a scan tool while listening for the contactor to open and close. The Battery Charging System Positive Contactor should be heard opening and closing.

• If the Battery Charging System Positive Contactor does not open and close, refer to Battery Charging System Positive Contactor Diagnosis.

8. Command the Hybrid/EV Battery Multifunction Contactor OPEN and CLOSED with a scan tool while listening for the contactor to open and close. The Hybrid/EV Battery Multifunction Contactor should be heard opening and closing.

• If the Hybrid/EV Battery Multifunction Contactor does not open and close, refer to Hybrid/EV Battery Multifunction Contactor Diagnosis.

Circuit/System Testing

P0AE2 or P0AE4 - Hybrid/EV Battery Precharge Transistor 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 Pack Precharge Transistor 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 11 and ground.
10. Vehicle in Service Mode, command the Hybrid/EV Battery Pack Precharge Transistor 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.

P1EC3, P1EC4, or P1EC5 - Hybrid/EV Battery Pack Heater Transistor 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. Connect the EL-50211 low voltage jumper harness extension.
7. Connect a test lamp between EL-50211 low voltage jumper harness extension test terminal and ground.
8. Vehicle in Service Mode, command the Hybrid/EV Battery Pack Heater Transistor 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 K114B 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 K114B hybrid powertrain control module 2.

9. If all circuits test normal, replace the A4 hybrid/EV battery pack.

P1EC0 - Hybrid/EV Battery 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 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. Connect a test lamp between control circuit terminal 2 and ground.
12. 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.

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