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 Descriptor

DTC B147F 02: Battery Saver Relay Reset Secondary Circuit Short to Ground

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Battery Saver Relay - Control Circuit

B147F 02

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Circuit/System Description

The battery saver mode reduces the parasitic load of some modules during overseas shipment or during vehicle storage conditions. This improves the drain time on the battery of up to 70 days without the battery going dead. When the vehicle is in transport/storage, some features may have reduce functionality as a result being in the battery saver mode, such as disabling the Remote Function Actuator or content theft features.

The battery saver mode incorporates a latching relay that when enabled disconnects some modules from their ignition off power or memory power sources. Battery saver mode is initiated by starting the vehicle and then turning the ignition key into the crank position for greater than 15 seconds. The mode is disengaged by repeating the previous process causing the relay to latch in the other direction. This feature can be used as many times as necessary if the vehicle is to be stored for an extended period of time.

Conditions for Running the DTC

    • The system voltage is between 9-16 V.
    • The DTC can only run when the output is activated.

Conditions for Setting the DTC

The BCM detects a short to ground in the battery saver relay reset circuit.

Action Taken When the DTC Sets

The module output driver will be shut down and not supply voltage to the battery saver relay reset circuit.

Conditions for Clearing the DTC

    • The current DTC will clear when the module request for the output is removed or the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Reference Information

Schematic Reference

    •  Body Control System Schematics
    •  Power Distribution Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Mode Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the KR104A battery saver relay.
  2. Connect a test lamp between the relay control circuit and ground.
  3. Enable and disable the battery saver mode. The test lamp should turn ON and OFF when changing the battery saver relay latch positions.
  4. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
    If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K9 BCM.
  5. If all circuits test normal, test or replace the KR104A battery saver relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Refer to Control Module References for BCM replacement, setup, and programming