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Home >> Cadillac >> 2017 >> CTS Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 185 (Cellular System, Entertainment System And Navigation System) >> Diagnostic Information and Procedures >> DTC B2470: Cellular Phone Antenna Circuit Malfunction (without EF7 or Z49) >> Circuit/System Testing >> With Navigation Radio
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With Navigation Radio

WARNING: This page is about a different car, the 2016 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF and all vehicle systems OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 min for all vehicle systems to power down.
  2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903  GM OnStar® antenna diagnostic tool kit to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON.
  3. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
    • If the DTC sets 

      Replace the K73 Telematics Communication Interface Control Module.

    • If the DTC does not set 
  4. Ignition OFF.
  5. Disconnect the EL-49903  GM OnStar® antenna diagnostic tool kit from the K73 Telematics Communication Interface Control Module
  6. Connect the coax cable to the K73 Telematics Communications Interface Control Module and disconnect the coax cable from the T15 Navigation Antenna Signal Splitter, ignition ON.
  7. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
    • If less than 4.5 V 
    1. Ignition OFF.
    2. Test the coax cable. Refer to Component Testing .
      • If the coax cable does not pass the test, replace the coax cable.
      • If the coax cable passes the test, test or replace the K73 Telematics Communications Interface Control Module.
    • If greater than 5.5 V 
    1. Ignition OFF.
    2. Test the coax cable. Refer to Component Testing .
      • If the coax cable does not pass the test, replace the coax cable.
      • If the coax cable passes the test, test or replace the K73 Telematics Communications Interface Control Module.
    • If between 4.5-5.5 V 
  8. Ignition OFF, connect the coax cable to the T15 Navigation Antenna Signal Splitter and disconnect the coax cable from the T4G Cellular Phone, Navigation and Digital Radio Antenna, ignition ON.
  9. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
    • If less than 4.5 V 
    1. Ignition OFF.
    2. Test the coax cable. Refer to Component Testing .
      • If the coax cable does not pass the test, replace the coax cable.
      • If the coax cable passes the test, test or replace the T15 Navigation Antenna Signal Splitter.
    • If greater than 5.5 V 
    1. Ignition OFF.
    2. Test the coax cable. Refer to Component Testing .
      • If the coax cable does not pass the test, replace the coax cable.
      • If the coax cable passes the test, test or replace the T15 Navigation Antenna Signal Splitter.
    • If between 4.5-5.5 V 
  10. Test or replace the T4G Cellular Phone, Navigation and Digital Radio Antenna.
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