Circuit/System Testing (without Navigation Radio)

NOTE:

The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.
The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 minutes after turning the ignition ON for the GPS satellites to acquire vehicle signal.

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 two minutes for all vehicle systems to power down.
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 module. Place the test antenna on the roof of the vehicle.
Ignition ON.
Verify that an OnStar advisor can locate the vehicle after performing a blue button press.
- If the advisor can not locate the vehicle
  Replace the K73 telematics communication interface control module.
- If the advisor can locate the vehicle
Ignition OFF, disconnect the K73 telematics communication interface module coax at the T4G cellular phone, navigation, and digital radio antenna.
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.
- If the coax cable passes the test
Test or replace the T4G cellular phone, navigation, and digital radio antenna.