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Home >> Cadillac >> 2019 >> XT4 Sport, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 197 (Keyless Entry System And Remote Functions) >> Diagnostic Information and Procedures >> DTC B3122 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2019 Cadillac XT5. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the T10J Keyless Entry Antenna - Center Console Front, ignition ON.
  2. Test for less than 1 V between the signal circuit terminal 1 and ground.
    • If 1 V or greater 
    1. Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K84 Keyless Entry Control Module.
    • Go to next step: If less than 1 V 
    3. NOTE:

    When using the MIN MAX function, autorange on the DMM may not function properly. To ensure accurate test results, turn off autorange and manually set the DMM range to 0 - 400/600 V.

  3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the PEAK MIN MAX function. Turn off autorange and manually set the DMM range to 0 - 400/600 V.
  4. Activate the antenna by pressing the ignition mode switch.
  5. Verify the MAX voltage captured by the DMM is greater than 1 V.
    • If 1 V or less 
    1. Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module.
    2. Test for infinite resistance between the signal circuit 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 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K84 Keyless Entry Control Module.
    • Go to next step: If greater than 1 V 
  6. Test for less than 1 V between the low reference circuit terminal 2 and ground.
    • If 1 V or greater 
    1. Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module, ignition ON.
    2. Test for less than 1 V between the low reference circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K84 Keyless Entry Control Module.
    • Go to next step: If less than 1 V 
    7. NOTE:

    When using the MIN MAX function, autorange on the DMM may not function properly. To ensure accurate test results, turn off autorange and manually set the DMM range to 0 - 400/600 V.

  7. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the PEAK MIN MAX function. Turn off autorange and manually set the DMM range to 0 - 400/600 V.
  8. Activate the antenna by pressing the ignition mode switch.
  9. Verify the MAX voltage captured by the DMM is greater than 1 V.
    • If 1 V or less 
    1. Ignition OFF, disconnect the harness connector at the K84 Keyless Entry Control Module.
    2. Test for infinite resistance between the low reference circuit 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 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K84 Keyless Entry Control Module.
    • Go to next step: If greater than 1 V 
  10. Replace the T10J Keyless Entry Antenna - Center Console Front.
  11. Activate the antenna by pressing the ignition mode switch.
  12. Verify DTC B3122 is not set.
    • If DTC B3122 is set 

      Replace the K84 Keyless Entry Control Module.

    • Go to next step: If DTC B3122 is not set 
  13. All OK.
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