P1A2A

DTC P1A22, P1A23, P1A29, P1A2A, P1A30, or P1A31

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 P1A22
- Hybrid Battery 1 Circuit Low Voltage

DTC P1A23
- Hybrid Battery 1 Circuit High Voltage

DTC P1A29
- Hybrid Battery 2 Circuit Low Voltage

DTC P1A2A
- Hybrid Battery 2 Circuit High Voltage

DTC P1A30
- Hybrid Battery 3 Circuit Low Voltage

DTC P1A31
- Hybrid Battery 3 Circuit High Voltage

Circuit/System Description

The battery energy control module (BECM) monitors the 3 module voltage sensors for low or high voltage condition.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

P1A22

Module 1 voltage raw A/D is less than 0.5 V.

P1A23

Module 1 voltage raw A/D is greater than 4.5 V.

P1A29

Module 2 voltage raw A/D is less than 0.5 V.

P1A2A

Module 2 voltage raw A/D is greater than 4.5 V.

P1A30

Module 3 voltage raw A/D is less than 0.5 V.

P1A31

Module 3 voltage raw A/D is greater than 4.5 V.

Action Taken When the DTC Sets

Hybrid system is inactive.

Conditions for Clearing the DTC

Module voltage raw A/D returns to normal operating range.

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

Generator Battery Carrier Description and Operation (Description and Operation)
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)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

J 35616 GM Approved Terminal Test Kit

Circuit/System Testing

Warning

To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.

Warning

To help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.

Note: In order to avoid damaging BECM X1 and X2 connector terminals, the proper test probes should be used. The proper test probes are as follows:

* J-35616-65B for female terminals
* J-35616-64B for male terminals

1. If there are any other DTCs set as current, diagnose those first, including any clearing of codes.
2. Verify that the DTC is set as current.
3. Scan and record the generator battery voltage parameters for battery 1, battery 2, and battery 3.
4. Measure the voltage of the generator battery that set the DTC and compare it to the parameter scanned value. Refer to Generator Battery Temperature Sensor Replacement (Generator Battery Temperature Sensor Replacement).

• If the voltages are within 0.5 V, replace the generator battery.

5. Disconnect harness connector X2 from the BECM. Refer to Hybrid Battery Service Disconnect/Connect (Procedures).
6. Test for 1.3-1.7k ohm between the following circuits:

* X2 terminal 1 to Generator Battery 1-X1
* X2 terminal 11 to Generator Battery 1-X2
* X2 terminal 2 to Generator Battery 2-X2
* X2 terminal 12 to Generator Battery 3-X2

• If not within specified range, replace the harness assembly.

7. If all circuits test normal, replace the BECM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Generator Battery Temperature Sensor Replacement (Generator Battery Temperature Sensor Replacement)
* Generator Battery Replacement (Generator Battery Replacement)
* Control Module References (Programming and Relearning) for BECM replacement, programming and setup