GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0B3D: Hybrid Battery 1 Circuit Low Voltage

DTC P0B42: Hybrid Battery 2 Circuit Low Voltage

DTC P0B47: Hybrid Battery 3 Circuit Low Voltage

DTC P0B4C: Hybrid Battery 4 Circuit Low Voltage

DTC P0B51: Hybrid Battery 5 Circuit Low Voltage

DTC P0B56: Hybrid Battery 6 Circuit Low Voltage

DTC P0B5B: Hybrid Battery 7 Circuit Low Voltage

DTC P0B60: Hybrid Battery 8 Circuit Low Voltage

DTC P0B65: Hybrid Battery 9 Circuit Low Voltage

DTC P0B6A: Hybrid Battery 10 Circuit Low Voltage

DTC P0B6F: Hybrid Battery 11 Circuit Low Voltage

DTC P0B74: Hybrid Battery 12 Circuit Low Voltage

DTC P0B79: Hybrid Battery 13 Circuit Low Voltage

DTC P0B7E: Hybrid Battery 14 Circuit Low Voltage

DTC P0B83: Hybrid Battery 15 Circuit Low Voltage

DTC P0B88: Hybrid Battery 16 Circuit Low Voltage

DTC P0B8D: Hybrid Battery 17 Circuit Low Voltage

DTC P0B92: Hybrid Battery 18 Circuit Low Voltage

DTC P0B97: Hybrid Battery 19 Circuit Low Voltage

DTC P0B9C: Hybrid Battery 20 Circuit Low Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Battery 1 Voltage

P1AE7

P0B3D, P1A1F

P0B3E, P1A4E

P0B3C, P0BBD

Battery 2 Voltage

P1AE7

P0B42, P1A1F

P0B43, P1A4E

P0B41, P0BBD

Battery 3 Voltage

P1AE7

P0B47, P1A1F

P0B48, P1A4E

P0B46, P0BBD

Battery 4 Voltage

P1AE7

P0B4C, P1A1F

P0B4D, P1A4E

P0B4B, P0BBD

Battery 5 Voltage

P1AE7

P0B51, P1A1F

P0B52, P1A4E

P0B50, P0BBD

Battery 6 Voltage

P1AE7

P0B56, P1A1F

P0B57, P1A4E

P0B55, P0BBD

Battery 7 Voltage

P1AE7

P0B5B, P1A1F

P0B5C, P1A4E

P0B5A, P0BBD

Battery 8 Voltage

P1AE7

P0B60, P1A1F

P0B61, P1A4E

P0B5F, P0BBD

Battery 9 Voltage

P1AE7

P0B65, P1A1F

P0B66, P1A4E

P0B64, P0BBD

Battery 10 Voltage

P1AE7

P0B6A, P1A1F

P0B6B, P1A4E

P0B69, P0BBD

Battery 11 Voltage

P1AE7

P0B6F, P1A1F

P0B70, P1A4E

P0B6E, P0BBD

Battery 12 Voltage

P1AE7

P0B74, P1A1F

P0B75, P1A4E

P0B73, P0BBD

Battery 13 Voltage

P1AE7

P0B79, P1A1F

P0B7A, P1A4E

P0B78, P0BBD

Battery 14 Voltage

P1AE7

P0B7E, P1A1F

P0B7F, P1A4E

P0B7D, P0BBD

Battery 15 Voltage

P1AE7

P0B83, P1A1F

P0B84, P1A4E

P0B82, P0BBD

Battery 16 Voltage

P1AE7

P0B88, P1A1F

P0B89, P1A4E

P0B87, P0BBD

Battery 17 Voltage

P1AE7

P0B8D, P1A1F

P0B8E, P1A4E

P0B8C, P0BBD

Battery 18 Voltage

P1AE7

P0B92, P1A1F

P0B93, P1A4E

P0B91, P0BBD

Battery 19 Voltage

P1AE7

P0B97, P1A1F

P0B98, P1A4E

P0B96, P0BBD

Battery 20 Voltage

P1AE7

P0B9C, P1A1F

P0B9D, P1A4E

P0B9B, P0BBD

Typical Scan Tool Data

Hybrid Battery 1-20

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Ignition ON

Parameter Normal Range: 13-19 Volts

Battery 1-20 Voltage

13-19 Volts

0 Volts

--

Circuit/System Description

The drive motor generator battery control module is also referred to as the battery energy control module (BECM). The BECM will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is communicated from the BECM to the hybrid powertrain control module (HPCM) through serial data. The HPCM is the host controller for diagnostic trouble code (DTC) information.

The hybrid battery assembly consists of 40 individual batteries. Each battery is rated at 7.2 V. The batteries are connected together in a series circuit. The BECM monitors the hybrid battery voltage on every two batteries for a total of 20 locations, across the battery assembly. If a hybrid battery voltage measurement drops below a calibrated value, this DTC will set.

Conditions for Running the DTC

    • DTC P0A1F is not set.
    • The ignition is ON.
    • The 12 V battery voltage is 9-18 V.

Conditions for Setting the DTC

P0B3D, P0B42, P0B47, P0B4C, P0B51, P0B56, P0B5B, P0B60, P0B65, P0B6A, P0B6F, P0B74, P0B79, P0B7E, P0B83, P0B88, P0B8D, P0B92, and P0B97

Any two consecutive hybrid battery voltage values are less than 7.5 V for 1.5 seconds.

P0B9C

The hybrid battery 20 voltage is less than 7.5 V for 1.5 seconds.

Action Taken When the DTC Sets

    • The BECM commands the battery vent fan to high speed.
    • If more than 4 of these DTCs are set, the drive motor generator battery sends a message to the HPCM to reduce the power use limit to 50 percent.

Conditions for Clearing the DTC

DTCs P0B3D, P0B42, P0B47, P0B4C, P0B51, P0B56, P0B5B, P0B60, P0B65, P0B6A, P0B6F, P0B74, P0B79, P0B7E, P0B83, P0B88, P0B8D, P0B92, P0B97, and P0B9C are type B DTCs.

Reference Information

Schematic Reference

Hybrid Energy Storage Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Battery System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

    • EL-48571 High Voltage Battery Pin Out Box
    • EL-48900 HEV Safety Kit

Circuit/System Verification

Ignition ON, observe the scan tool Hybrid Battery 1-20 parameters. Each reading should be between 13-19 Volts.

Circuit/System Testing

    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.
    Failure to follow the procedures exactly as written may result in serious injury or death.

  1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
  2. Remove the drive motor generator battery upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement.
  3. Disconnect the X4 harness connector at the BECM.
  4. Connect the EL-48571 high voltage battery pin out box to the X4 harness connector.
  5. Install the high voltage manual disconnect lever.
  6. Test for 13-19 volts across all 20 battery voltage reference circuits.
  7. If not within the specified range, replace the drive motor battery assembly.
  8. If all circuits test normal, replace the drive motor generator battery control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

    •  Drive Motor Generator Battery Replacement
    •  Control Module References - for drive motor generator battery control module replacement, setup and programming.