P0AF8
DTC P0AF8
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 P0AF8
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Hybrid Battery System Voltage
Circuit/System Description
As a means to verify the battery energy control module's voltage measuring ability, the battery energy control module compares it's own measurement of the hybrid battery pack voltage to that measured internally at the starter/generator control module when the contactors are closed. This provides a second source of the battery energy control module's hybrid battery pack voltage rationality.
Conditions for Running the DTC
* Main contactor is closed
* None of the following DTCs are set: P0ABB, P0ABC, P0ABD, P1A5D, U182A
Conditions for Setting the DTC
The difference between the high voltage battery voltage measured at the battery energy control module and the voltage measured at the motor controller, internal to the starter/generator control module, is greater than 5.77 V.
Action Taken When the DTC Sets
* DTC P0AF8 is a type B DTC
* 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
DTC P0AF8 is a type B DTC
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-48900 - HEV Safety Kit
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
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.
1. Verify no other DTCs are set in the in the K59 starter/generator control module.
• If other DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If no other DTCs are set
2. Ignition ON, observe and record the 32 scan tool Hybrid Battery Cell Voltage parameters. Add the values together to calculate hybrid battery pack voltage based on the cell voltages.
3. Verify the calculated hybrid battery pack voltage from step 2 is within 5.77 V of the scan tool High Voltage Battery Voltage parameter.
• If not within 5.77 V
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. Verify the battery energy control module high voltage measuring harness is not cut, chafed, or otherwise damaged.
• If the harness is damaged, replace the harness.
• If the harness is not damaged
3. Replace the K16 battery energy control module
• If within 5.77 V
4. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* 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