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Circuit/System Testing

WARNING: This page is about a different car, the 2021 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/vehicle OFF and all vehicle systems Off, disconnect the harness connector at the P50 Regulatory Emergency Call Backup Speaker. Ignition ON/vehicle in service mode.
  2. Test for 5 - 7 V between the audio control circuit terminal 2 and ground.
    • If less than 5 V 
    1. Ignition/vehicle OFF, disconnect the harness connector X1 at the K73 Telematics Control Module.
    2. Test circuit 4770 for a short to ground.
      • If a short to ground is found, repair the fault on the circuit.
      • Go to next step: If a short to ground is not found
    3. Test circuit 4770 for an open/high resistance.
      • If an open/high resistance is found, repair the fault on the circuit or ground connection
      • If an open/high resistance is not found.

        Replace the K73 Telematics Control Module

    • If greater than 7 V 
    1. Ignition/vehicle OFF, disconnect the harness connector X1 at the K73 Communication Interface Module. Ignition ON/vehicle in service mode.
    2. Test circuit 4770 for a short to voltage.
      • If a short to voltage is found repair the fault on the circuit.
      • If no short to voltage is found, replace the K73 Telematics Control Module.
    • Go to next step: If between 5 - 7 V 
  3. Test or replace the P50 Regulatory Emergency Call Backup Speaker.
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