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Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify that DTCs P0A95, P0AC1, P0C76, or P1A07 are not set, and that no HPCM DTCs are set.
    • If the specified DTCs are set, diagnose those DTCs first.
  2. Verify the 125 A HV fuse in the manual disconnect lever is not open.
    3. WARNING: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:
    • Safety glasses with appropriate side shields when within 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 at all times when working with the high voltage battery assembly, whether the system is energized or not.

    Failure to follow the procedure exactly as written may result in serious injury or death.
    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.
  3. Connect the EL-48458  at the drive motor generator power inverter module (PIM). Refer to the EL-48458  installation procedure located in High Voltage System Diagnosis (EL-48458) .
  4. Ignition ON, attempt to precharge the HV system by moving the HV contactor relay switch on the tester to the closed position. Verify that the hi-voltage greater than 60 V LED does not illuminate.
    • If the LED illuminates, replace the drive motor generator power inverter module.
  5. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling .
  6. Remove the EL-48458  . Refer to the removal procedure located in High Voltage System Diagnosis (EL-48458) .
  7. Inspect and test the HV 300 V positive and negative DC cables and connection points between the drive motor generator battery X1 and X2 connectors and the drive motor generator power inverter module (PIM) assembly X2 and X3 connectors for an open/high resistance condition.
    • If an open/high resistance condition is found on the HV cables or connection points, replace the drive motor battery 300 V positive and negative cable.
  8. Remove the drive motor generator battery upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement .
  9. Inspect and test the HV DC cables and connection points between the terminals listed below for an open/high resistance condition.
    • Negative output terminal X2 and the negative contactor relay terminal X3
    • Positive output terminal X1 and the positive contactor relay terminal X3
    • Negative contactor relay terminal X2 and battery module 1
    • Positive contactor relay terminal X2 and battery module 40
    • Positive contactor relay terminal X3 and the current limit relay terminal 2 X4
    • If an open/high resistance condition is found on the HV cables or connection points, replace the appropriate component.
  10. Test for 11-13 Ω between terminal 1 X3 at the current limit relay and terminal X2 at the positive contactor relay.
    • If not within the specified range, test or replace the current limit resistor.
  11. Connect the 12 V battery.
  12. Install the HV manual disconnect lever.
  13. Command the negative contactor relay closed with a scan tool. Test for less than 0.5 Ω between terminals X2 and X3 of the negative contactor relay.
    • If greater than the specified value, test or replace the negative contactor relay.
  14. Command the positive contactor relay closed with a scan tool. Test for less than 0.5 Ω between terminals X2 and X3 of the positive contactor relay.
    • If greater than the specified value, test or replace the positive contactor relay.
  15. Disconnect the X1 harness connector at the negative contactor relay.
  16. Test for infinite resistance between the negative contactor relay terminal X2 and terminal X3.
    • If less than the specified value, test or replace the negative contactor relay.
  17. Ignition OFF, test for less than 5 Ω between the negative contactor relay ground circuit terminal 2 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  18. Connect a test lamp between the negative contactor relay control circuit terminal 1 X1 and the ground circuit terminal 2 X1.
  19. Command the negative contactor relay open and closed with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the drive motor generator battery control module.
    • 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 drive motor generator battery control module.
  20. Disconnect the X1 harness connector at the positive contactor relay.
  21. Test for infinite resistance between the positive contactor relay terminal X2 and terminal X3.
    • If less than the specified value, test or replace the positive contactor relay.
  22. Ignition OFF, test for less than 5 Ω between the positive contactor relay ground circuit terminal 2 X1 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  23. Connect a test lamp between the positive contactor relay control circuit terminal 1 X1 and the ground circuit terminal 2 X1.
  24. Command the positive contactor relay open and closed with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the drive motor generator battery control module.
    • 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 drive motor generator battery control module.
  25. Disconnect the X1 and X2 harness connectors at the current limit relay.
  26. Test for infinite resistance between the current limit relay terminal 1 X3 and terminal 2 X4.
    • If less than the specified value, test or replace the current limit relay.
  27. Ignition OFF, test for less than 5 Ω between the current limit relay ground circuit terminal 6 X2 and ground.
    • If greater than the specified value, test the ground circuit for an open/high resistance.
  28. Connect a test lamp between the current limit relay control circuit terminal 5 X1 and the ground circuit terminal 6 X2.
  29. Command the current limit relay open and closed with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the drive motor generator battery control module.
    • 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 drive motor generator battery control module.
  30. If all circuits test normal, test or replace the current limit relay and the positive and negative contactor relays.
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