P0AFB
DTC P0AFA or P0AFB
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 Descriptor
DTC P0AFA
-
Hybrid Battery System Voltage Low
DTC P0AFB
-
Hybrid Battery System Voltage High
Circuit/System Description
The hybrid battery pack contains a total of 32 cells in the hybrid/EV battery pack. These cells are electrically connected in series. Each individual cell is rated at 3.7 V, for a nominal system voltage of 118 V DC. The battery cells are grouped together into two sections, each with 16 cells.
The battery energy control module monitors the voltage of the 32 battery cells. A voltage sense circuit is attached to each individual cell. Each of these circuits terminate at a connector located on the top surface of the battery section. A serviceable auxiliary battery wiring harness connectors the voltage sense circuits to the battery energy control module, located directly above the hybrid battery section 1 and hybrid battery section 2. The battery energy control module also monitors the hybrid battery pack voltage in it's entirety. The battery energy control module compares the voltage of the entire pack to that of the sum of the voltages measures at each cell.
Conditions for Running the DTC
None of the following DTCs are set: P0ABB, P0ABC, P0ABD, P0AF8, P1A5D, U182A
OR
None of the following DTCs are set: P0B3B, P0B3C, P0B3D, P0B3E, P0B40, P0B41, P0B42, P0B43, P0B45, P0B46, P0B47, P0B48, P0B4A, P0B4B, P0B4C, P0B4D, P0B4F, P0B50, P0B51, P0B52, P0B54, P0B55, P0B56, P0B57, P0B59, P0B5A, P0B5B, P0B5C, P0B5E, P0B5F, P0B60, P0B61, P0B63, P0B64, P0B65, P0B66, P0B68, P0B69, P0B6A, P0B6B, P0B6D, P0B6E, P0B6F, P0B70, P0B72, P0B73, P0B74, P0B75, P0B77, P0B78, P0B79, P0B7A, P0B7C, P0B7D, P0B7E, P0B7F, P0B81, P0B82, P0B83, P0B84, P0B86, P0B87, P0B88, P0B89, P0B8B, P0B8C, P0B8D, P0B8E, P0B90, P0B91, P0B92, P0B93, P0B95,P0B96, P0B97, P0B98, P0B9A, P0B9B, P0B9C, P0B9D, P0B9F, P0BA0, P0BA1, P0BA2, P0BA4, P0BA5, P0BA6, P0BA7, P0BA9, P0BAA, P0BAB, P0BAC, P0BAE, P0BAF, P0BB0, P0BB1, P0BB3, P0BB4, P0BB5, P0BB6, P0BB8, P0BB9, P0BBA, P0BBB, P1B16, P1B17, P1B18, P1B19, P1B1A, P1B1B, P1B1C, P1B1D, P1B1E, P1B1F, P1B20, P1B21, P1B22, P1B23, P1B24, P1B25, P1B26, P1B27, P1B28, P1B29, P1B2A, P1B2B, P1B2C, P1B2D
Conditions for Setting the DTC
DTC P0AFA
Battery pack voltage is less than 61.91 V
OR
Any individual cell voltage is less than 1.93 V
DTC P0AFB
Battery pack voltage is greater than 136.49 V
OR
Any individual cell voltage is greater than 4.26 V
Action Taken When the DTC Sets
* DTCs P0AFA and P0AFB are type B DTCs
* The vehicle operates in a low battery mode with the high voltage contactors closed, but no hybrid functions will occur
Conditions for Clearing the DTC
* DTCs P0AFA and P0AFB are type B DTCs
* DTCs P0AFA and P0AFB are secure DTCs. The Clear Secured High Voltage DTCs Reading and Clearing Diagnostic Trouble Codes procedure must be performed to prevent resetting the DTC.
Diagnostic Aids
The following two tables should be used to determine the switch setting when using the EL-48571-30 - High Voltage Battery Pin Out Box.
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Connector End Views By Name
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-48571-30 - High Voltage Battery Pin Out Box
EL-48900 - HEV Safety Kit
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
1. Ignition ON.
2. Verify that each of the scan tool Hybrid Battery Cell Voltage 1-32 parameters are between 3.0-4.1 V and all parameters are within 0.1 V of each other.
• If any parameter is not between 3.0-4.1 V or is not within 0.1 V of the others
Refer to Circuit/System Testing.
• If all parameter are between 3.0-4.1 V and are within 0.1 V of each other
3. All OK.
Circuit/System Testing
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 eAssist battery pack assembly will utilize an exchange program. Please consult the most recent revision of bulletin/PI# PIC5520, available in Service Information♦(SI), for a list of approved eAssist battery pack assembly service procedures. Components that may be removed and serviced without exchanging the complete battery pack assembly are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.
Note:
In High Voltage Disabling High Voltage Disabling , perform the disabling procedure for servicing components within the A4 hybrid/EV battery pack. The C4A hybrid/EV battery section 1 and C4B hybrid/EV battery section 2 will be disconnected as part of the disabling procedure.
1. Ignition OFF, disable high voltage at the A4 hybrid battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Disconnect the X1 and X2 harness connectors K16 battery energy control module.
3. Connect the EL-48571-30 - high voltage battery pin out box to the appropriate K16 battery energy control module harness connector.
4. Insert the DMM probes into the EL-48571-30 test cavities.
Note:
* The DMM must be set to the DC voltage setting.
* Not all 24 switch positions of the EL-48571-30 will be used.
5. Measure and record the voltage of each of the cells by cycling the EL-48571-30 through each of the 16 switch positions.
6. Verify that each cell voltage reading is 3.0-4.1 V and all cell voltage readings are within 0.1 V of each other.
• If any parameter is not between 3.0-4.1 V or is not within 0.1 V of the others
1. Inspect the appropriate voltage signal circuit and low reference circuit for a short to ground or an open/high resistance.
• If a short to ground or an open/high resistance is found, replace the appropriate battery energy control module high voltage measuring harness.
• If a short to ground or an open/high resistance is not found
2. Replace the C4A hybrid/EV battery section 1 and C4B hybrid/EV battery section 2.
• If all parameter are between 3.0-4.1 V and are within 0.1 V of each other
7. Replace the K16 battery energy control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Generator Battery Replacement Generator Battery Replacement
* Battery Energy Control Module Wiring Harness Replacement (BDU,BECM and BPIM) Battery Energy Control Module Wiring Harness Replacement (BDU,BECM and BPIM)Battery Energy Control Module Wiring Harness Replacement (HV Measuring Harness 1 and 2) Battery Energy Control Module Wiring Harness Replacement (HV Measuring Harness 1 and 2)
* Control Module References Programming and Relearning for battery energy control module replacement, programming and setup