P1B11
DTC P1B11
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 P1B11
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Drive Motor Control Module Hybrid AC Voltage System Isolation Lost
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
This DTC runs at all times
Conditions for Setting the DTC
The starter/generator control module detects an AC voltage short to chassis ground.
Action Taken When the DTC Sets
* DTC P1B11 is a type A DTC
* 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
* DTC P1B11 is a type A DTC
* 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
EL-50772 - Insulation Multimeter
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.
Note:
In High Voltage Disabling High Voltage Disabling , perform the disabling procedure for servicing components within the energy storage system. 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/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. Disconnect the U, V, and W three phase lugs at the K59 starter/generator control module.
Note:
The following continuity tests must be performed using the EL-50772 - Insulation Multimeter. Select the Isolation test setting, then select the 500 V range.
3. Test for greater than 400K ohms between the terminals listed below and chassis ground with the EL-50772 - Insulation Multimeter set on the Isolation test setting:
* 3 phase cable terminal U - cable side lug
* 3 phase cable terminal V - cable side lug
* 3 phase cable terminal W - cable side lug
• If 400K ohms or less
1. Disconnect the U, V, and W three phase lugs at the A15 starter/generator.
2. Test for greater than U, V, and W three phase studs at the A15 starter/generator and chassis ground with the EL-50772 - Insulation Multimeter set on the Isolation test setting.
• If 400K ohms or less, replace the A15 starter/generator.
• If greater than 400K ohms
3. Replace the high voltage 3 phase cables.
• If greater than 400K ohms
Note:
The following continuity tests must be performed using the EL-50772 - Insulation Multimeter. Select the Isolation test setting, then select the 500 V range.
4. Test for greater than 400K ohms between the terminals listed below and chassis ground with the EL-50772 - Insulation Multimeter set on the Isolation test setting:
* 3 phase terminal U - K59 starter/generator control module stud
* 3 phase terminal V - K59 starter/generator control module stud
* 3 phase terminal W - K59 starter/generator control module stud
• If 400K ohms or less
1. Disconnect and remove the two wiring junction blocks from the A4 hybrid/EV battery pack.
2. Test for greater than U, V, and W three phase studs at the K59 starter/generator control module and chassis ground with the EL-50772 - Insulation Multimeter set on the Isolation test setting.
• If 400K ohms or less, replace the K59 starter/generator control module.
• If greater than 400K ohms
3. Replace the two wiring junction blocks.
• If greater than 400K ohms
5. Replace the C4A hybrid/EV battery section 1 and C4B hybrid/EV battery section 2.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Drive Motor Generator Battery Cable Replacement Drive Motor Generator Battery Cable Replacement
* Starter Generator Replacement Starter Generator Replacement
* Generator Battery Replacement Generator Battery Replacement
* Drive Motor Battery Wire Junction Block Relay Replacement Drive Motor Battery Wire Junction Block Relay Replacement
* Control Module References Programming and Relearning for starter/generator control module replacement, programming, and setup