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HOMESERVICE MANUALSCHEVROLET2009TAHOE BASE, 4.8 CREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 21 (HYBRID COOLING SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P0BC1CIRCUIT/SYSTEM TESTING
2009 Chevrolet Tahoe Base, 4.8 C

Circuit/System Testing

2009 Chevrolet Tahoe Base, 4.8 CSECTION Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
    WARNING: 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 case upper cover, front cover, and right side cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement .
  3. Disconnect the X2 connector at the GBCM.
  4. Ignition OFF, connect the 12 V battery.
  5. Ignition ON, test for greater than 0.9 V between the fan speed control circuit terminal 2 and ground.
    • If less than the specified value, replace the drive motor generator battery control module.
  6. Disconnect the harness connector at the vent fan relay.
  7. Ignition OFF, connect a test lamp at the vent fan relay harness connector between terminals 1 and 2. The test lamp should not illuminate.
    • If the test lamp illuminates, test the vent fan relay control circuit for a short to ground. If the circuit tests normal, replace the drive motor generator battery control module.
  8. Ignition ON, connect a test lamp at the vent fan relay harness connector terminal 4 and ground. The test lamp should not illuminate.
    • If the test lamp illuminates, repair the short to B+ on the supply voltage circuit between the battery fan relay and the battery vent motor. If the circuit tests normal, test or replace the relay.
  9. Ignition OFF, disconnect the inline harness connector at the drive motor generator battery vent fan.
  10. Ignition ON, connect a test lamp at the battery vent fan harness connector terminal 4. The test lamp should not illuminate.
    • If the test lamp illuminates, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the drive motor generator battery control module.
  11. Test for infinite resistance between terminal 3 and 4 on the drive motor generator battery vent fan relay.
    • If less than the specified value, replace the drive motor generator battery vent fan relay.
  12. If all circuits test normal, replace the drive motor generator battery vent fan.
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  • • You are missing required tools, torque specs, or safe lifting equipment.
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