Circuit/System Testing

WARNING: This page is about a different car, the 2018 Cadillac XTS. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF/vehicle OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module.
Attach both leads of the EL-49903 - 1 OnStar test antenna to the EL-49903 - 5 combiner. Using the EL-49903 - 6 coax cable attach the grey connector to the combiner and the brown connector to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON.
Verify DTC B2462 is not set or that the OnStar advisor can locate the vehicle.
- If DTC B2462 is set or the advisor can not locate the vehicle
  Replace the K73 Telematics Communication Interface Control Module.
- Go to next step: If DTC B2462 is not set or the advisor can locate the vehicle
Test the coax cable between the K73 Telematics Communication Interface Control Module and the T4G Cellular Phone, Navigation, and Digital Radio Antenna. Refer to component testing.
- If the coax cable does not pass the test
  Replace the coax cable.
- Go to next step: If the coax cable passes the test
Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.