FixVault
Home › Cadillac › 2020 › XT6 Sport › Repair and Diagnosis › External Pages › Different car › Section 339 (Plug-In Charging System) › Diagnostic Information and Procedures › Plug-In Charging Indicator Malfunction › Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2023 GMC Hummer EV. However, it is still accessible from the selected car via links, so may be relevant.
  1. Vehicle OFF, disconnect the harness connector at the E85 Charge Port Housing Lamp.
  2. Test for less than 10 Ω between the low reference terminal 1 and ground.
    • If 10 Ω or greater 

      Repair the open/high resistance in the circuit.

    • Go to next step: If less than 10 Ω 
    3. NOTE:

    If the drive motor battery charger cable is connected. The drive motor battery charger cable must be disconnected for more than 10 s before performing the next step.

  3. Vehicle OFF. Connect a test lamp between the B+ terminal 2 and ground.
  4. Vehicle On. Verify the test lamp illuminates.
    • If the test lamp does not illuminate 
    1. Check for a open fuse.
      • If the fuse is open

        Check for less than infinite resistance between circuit and ground.

      • If less than infinite resistance
      • Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    2. Replace the E85 Charge Port Housing Lamp
      • If the fuse is not blown
      • Repair open/high resistance on the circuit.
      • Go to next step: If open/high resistance is not found
    3. Replace the E85 Charge Port Housing Lamp
    • Go to next step: If the test lamp illuminates 
  5. Vehicle ON. Test for between 3.5-12V between the LIN serial data circuit terminal 3 and ground.
    • If less than 3.5 V
    1. Vehicle OFF. Disconnect the X6 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the LIN serial data circuit terminal and ground.
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. Test for less than 2 ohms in the LIN serial data circuit end to end.
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • Go to next step: If 2 ohms or less
    4. K9 Body Control Module - Replace
    • If greater than 12 V
    1. Vehicle OFF. Disconnect the X6 harness connector at the K9 Body Control Module.
    2. Vehicle ON. Test for less than 1 V between the LIN serial data circuit terminal and ground.
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If 1 V or less
    3. K9 Body Control Module - Replace
    • If between 3.5 and 12 V
  6. Vehicle OFF. Inspect both harness and component connectors for contamination, corrosion, and terminal tension.
  7. Reconnect the harness connector at the E85 Charge Port Housing Lamp. Verify all connectors/terminals are fully seated.
  8. Re-preform the Circuit/System Verification.
    • If the vehicle charge indicator is still not operating properly 
    • E85 Charge Port Housing Lamp - Replace
    • Go to next step: If the vehicle charge indicator is now operating properly 
  9. All OK.
About FixVault