P1AF4
DTC P1AF4 or P1AF5
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this repair.
* 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 P1AF4
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Drive Motor Control Module Hybrid Battery Voltage Isolation Sensing Circuit 1 Low Voltage
DTC P1AF5
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Drive Motor Control Module 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 starter/generator control module places an AC signal on the high voltage system and monitors its amplitude. A reduced amplitude return signal indicates a loss of resistance to chassis ground. This isolation monitor method is sometimes referred to as the active isolation monitor.
Conditions for Running the DTC
P1AF4
* Power mode is RUN or CRANK.
* Contactors are closed.
P1AF5
Power mode is RUN or CRANK.
Conditions for Setting the DTC
P1AF4
The positive mid-pack voltage is less than 5 V.
P1AF5
The positive mid-pack voltage minus the high voltage is greater than 10 V.
Action Taken When the DTC Sets
DTCs P1AF4 and P1AF5 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P1AF4 and P1AF5 are Type B DTCs.
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 P1AF4 or P1AF5 is not set.
• If DTC P1AF4 or P1AF5 is set
Replace the K59 starter/generator control module.
• If DTC P1AF4 and P1AF5 are not 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