P0AAA
DTC P0AA8-P0AAA
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 P0AA8
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Hybrid Battery Voltage Isolation Sensing Performance
DTC P0AA9
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Hybrid Battery Voltage Isolation Sensing Circuit 1 Low Voltage
DTC P0AAA
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Hybrid Battery Voltage Isolation Sensing Circuit 1 High Voltage
Circuit/System Description
The vehicle is equipped with a high voltage isolation monitor feature. The purpose of the isolation monitor is to test the resistance between the high voltage positive and negative direct current (DC) bus and chassis ground. The isolation monitoring system measures the resistance between the high voltage system and chassis ground in the following way. The isolation monitoring system measures voltage potential difference between the positive battery mid pack voltage and chassis ground as well as the voltage difference between negative battery mid pack voltage and chassis ground. These voltage values are used by the starter/generator control module to calculate a resistance value between the high voltage bus and the chassis ground. If this resistance value is too low, a high voltage isolation fault has occurred.
Conditions for Running the DTC
P0AA8
* Power mode is RUN or CRANK.
* The starter/generator control module internal voltage sensor has no reported faults.
* None of the following DTCs are set: P0AA9, P0AAA, P1E0C, or P1E0D.
P0AA9
* Power mode is RUN or CRANK.
* Contactors are closed.
P0AAA
* Power mode is RUN or CRANK.
* None of the following DTCs are set: P0AA9, P0AAA, P1E0C, or P1E0D.
Conditions for Setting the DTC
P0AA8
The difference between the voltage measured at the starter/generator control module internal motor control processor and the sum of the mid-pack voltage positive sensor value and mid-pack voltage negative sensor value is greater than 15 V.
P0AA9
Voltage measured at the negative mid-pack voltage sensor is less than 5 V.
P0AAA
he difference between the voltage measured at the negative mid-pack voltage sensor and the starter/generator control module internal motor control processor high voltage value is greater than 15 V.
Action Taken When the DTC Sets
* DTCs P0AA8-P0AAA are type B DTCs.
* If the DTC sets while there is a loss of communication with the sensing and diagnostic module (SDM), the starter/generator control module will record the fault as a crash event and the DTC will become latched.
Conditions for Clearing the DTC
* DTCs P0AA8-P0AAA are type B DTCs.
* If the DTC is set as a latched DTC, the crash event must be cleared before the DTC will clear.
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. Ignition ON.
2. Verify DTC P0AA8, P0AA9, or P0AAA is not set.
• If any of the DTCs are set
Replace the K59 starter/generator control module.
• If none of the DTCs are set
3. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
Control Module References Programming and Relearning for starter/generator control module replacement, programming, and setup