Circuit/System Testing

Ignition OFF/vehicle OFF, disconnect the GPS coax cable connector at the K73 Telematics Communication Interface Control Module.
Connect the EL-49903-1 OnStar Test Antenna, Navn-Cell Comn to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON/vehicle in Service Mode.
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 that the OnStar advisor can locate the vehicle.
Ignition OFF/vehicle OFF, disconnect the EL-49903-1 OnStar Test Antenna, Navn-Cell Comn from the K73 Telematics Communication Interface Control Module
Disconnect the GPS coax cable at the T2RR Antenna - Roof Rear.
Test the coax cable between the K73 Telematics Communication Interface Control Module and the T2RR Antenna - Roof Rear. 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 T2RR Antenna - Roof Rear.