Diagnostic Instructions
DTC Descriptors
 DTC B2483 00: GPS Sensor Circuit Low 
 DTC B2484 00: GPS Sensor Circuit Open
Circuit/System Description
Tthe vehicle communication interface module (VCIM) receives GPS information from a specific navigation antenna located on the outside of the vehicle. The navigation antenna is connected to the VCIM via a shielded coaxial cable. The antenna cable also provides
a path for DC current for powering the antenna.
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 1 second. | 
 
Conditions for Setting the DTC
B2483
The VCIM detects a short to ground on the navigation antenna signal circuit. 
B2484
The VCIM detects an open/high resistance on the navigation antenna signal circuit. 
Action Taken When the DTC Sets
|     •  | The OnStar® status LED turns red. | 
 
|     •  | The OnStar® Call Center cannot locate the vehicle. | 
 
Conditions for Clearing the DTC
|     •  | The condition responsible for setting the DTC no longer exists. | 
 
|     •  | A history DTC clears after 50 malfunction-free ignition cycles. | 
 
Reference Information
Schematic Reference
OnStar Schematics
Connector End View Reference
Entertainment/Communication Connector End Views
Description and Operation
OnStar Description and Operation
Electrical Information Reference
- Disconnect the navigation antenna coax connector from the VCIM.
 
- Ignition ON, test for 4.5-5.5 V between the VCIM coax cable center conductor terminal at the module and ground. 
 
| ⇒ | If not within the specified range, replace the VCIM.  | 
 
- Reconnect the coax cable to the CIM. Disconnect the coax cable from the navigation antenna. 
 
- Test for 4.5-5.5 V between the coax cable center conductor and the outer shield. 
 
| ⇒ | If not within the specified range, replace the coax cable. | 
 
- If all circuits test normal, replace the navigation antenna. 
 
Repair Instructions
Perform the 
Diagnostic Repair Verification after completing the diagnostic procedure.