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Circuit/System Testing

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 includes the following steps:

  • 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.

Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

  • Safety glasses with appropriate side shields when within 15 meters (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 with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.

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

Battery Charger Bus Diagnostics

  1. Vehicle OFF, disable the high voltage at the T18 Battery Charger and the K1 14V Power Module. Refer to High Voltage Disabling .
  2. Disconnect the T18 Battery Charger high voltage DC connector.
  3. Disconnect the K1 14V Power Module high voltage connector.
  4. GM4494479Courtesy of GENERAL MOTORS COMPANY

    Disconnect the X367 harness connector at the A4 Hybrid/EV Battery Pack.

  5. Test for infinite resistance between the terminals the High voltage DC (+360 V) positive terminal A and the high voltage DC (-360 V) negative terminal B X367 harness connector.
    • If less than infinite resistance 

      Replace the high voltage DC cables. After the repair is complete with a scan tool, the Clear Secured High Voltage DTCs  reset function must be performed.

    • Go to next step: If infinite resistance 
  6. Test for less than 10 Ω between the terminals listed below:
    • High voltage DC (-360 V) negative terminal B harness connector at the T18 Battery Charger and the high voltage DC (-360 V) negative terminal B X367 harness connector at the A4 Hybrid/EV Battery Pack.
    • High voltage DC (+360 V) positive terminal A harness connector at the T18 Battery Charger and the high voltage DC (+360 V) negative terminal A X367 harness connector at the A4 Hybrid/EV Battery Pack.
    • If 10 Ω or greater 

      Replace the high voltage DC cables. After the repair is complete with a scan tool, the Clear Secured High Voltage DTCs  reset function must be performed.

    • Go to next step: If less than 10 Ω 
  7. Replace the T18 Battery Charger and the fuse, if open.
  8. Verify that DTC P0AF8 does not set while operating the vehicle within the Conditions for Running the DTC.
    • If DTC P0AF8 sets 

      Replace the K1 14V Power Module and the fuse, if open.

    • Go to next step: If DTC P0AF8 does not set 
  9. Verify that DTC P0AF8 does not set while operating the vehicle within the Conditions for Running the DTC.
    • If DTC P0AF8 sets 

      Replace the high voltage battery disconnect relay assembly.

    • Go to next step: If DTC P0AF8 does not set 
  10. All OK.

Battery Main Bus Diagnostics

  1. Vehicle OFF, disable the high voltage at the T6 Power Inverter Module and the A4 Hybrid/EV Battery Pack. Refer to High Voltage Disabling .
  2. Disconnect the X1 harness connector at the A4 Hybrid/EV Battery Pack.
  3. Disconnect the high voltage DC connector at the T6 power inverter module.
  4. Test for infinite resistance between the terminals the High voltage DC (+360 V) positive terminal A and the high voltage DC (-360 V) negative terminal B X1 harness connector.
    • If less than infinite resistance 

      Replace the high voltage DC cables. After the repair is complete with a scan tool, the Clear Secured High Voltage DTCs  reset function must be performed.

    • Go to next step: If infinite resistance 
  5. Test for less than 10 Ω between the terminals listed below:
    • High voltage DC (-360 V) negative terminal B X1 harness connector at the A4 Hybrid/EV Battery Pack and the high voltage DC (-360 V) negative terminal B harness connector at the T6 Power Inverter Module.
    • High voltage DC (+360 V) positive terminal A X1 harness connector at the A4 Hybrid/EV Battery Pack and the high voltage DC (+360 V) negative terminal A harness connector at the T6 Power Inverter Module.
    • If 10 Ω or greater 

      Replace the high voltage DC cables. After the repair is complete with a scan tool, the Clear Secured High Voltage DTCs  reset function must be performed.

    • Go to next step: If less than 10 Ω 
  6. Replace the T6 Power Inverter Module.
  7. Verify that DTC P0AF8 does not set while operating the vehicle within the Conditions for Running the DTC.
    • If DTC P0AF8 sets 

      Replace the high voltage battery disconnect relay assembly.

    • Go to next step: If DTC P0AF8 does not set 
  8. All OK.
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