Cellular Communications Diagnosis

CIRCUIT DESCRIPTION
The navigation antenna is connected to the Vehicle Interface Unit (VIU) with a RG-174 coax cable.
The VIU polls the data from the navigation antenna every 2.5 seconds.

CONDITIONS FOR RUNNING THE DTC
^ The ignition must be in the RUN or ACC position.
^ The system voltage is at least 9.5 volts and no more than 15.5 volts.
^ All the above conditions are present for greater than 2.5 seconds.

CONDITIONS FOR SETTING THE DTC
^ The VIU does not detect a GPS signal.
^ All the above conditions are present for greater than 2.5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The OnStar(R) status LED turns RED.
^ The OnStar(R) Call Center cannot locate the vehicle.

CONDITIONS FOR CLEARING THE DTC
^ The VIU detects the presence of a navigation antenna.
^ A history DTC clears after 50 malfunction free ignition cycles.
^ The VIU receives the clear DTC command from the scan tool.

TEST DESCRIPTION

Steps 1-7:

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests for proper ground on the navigation antenna.
3. This step tests the condition of the navigation antenna.