Circuit/System Testing (without Navigation Radio)

WARNING: This page is about a different car, the 2012 Buick Verano. However, it is still accessible from the selected car via links, so may be relevant.

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 2 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 control module.
Ignition ON, wait 5 minutes.
Verify that a call can be successfully placed to the OnStar Call Center by pressing the blue OnStar button.
- If unable to connect with the OnStar Call Center
  Test or replace the K73 telematics communication interface control module.
- If able to connect with the OnStar Call Center
Ignition OFF, disconnect the EL-49903 GM OnStar antenna diagnostic tool kit from the K73 telematics communication interface control module
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.