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Home >> Cadillac >> 2019 >> CTS Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 123 (Cellular System, Entertainment System, And Navigation System - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC B125B >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2018 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the radio antenna coax cable from the A11 Radio and from the Radio Antenna Amplifier/Module.
  2. Verify the antenna coax cable passes the coax cable component test. Refer to Component Testing.
    • If the coax cable does not pass the test 

      Replace the antenna coax cable

    • Go to next step: If the coax cable passes the test 
  3. Connect the antenna coax cable to the A11 Radio. Ignition ON, infotainment system ON.
  4. Verify a test lamp illuminates between the antenna coax cable center terminal and ground at the Radio Antenna Amplifier/Module connector.
    • If the test lamp does not illuminate 

      Replace the A11 Radio.

    • Go to next step: If the test lamp illuminates 
  5. Test or replace the Radio Antenna Amplifier/Module.
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