Diagnostic Instructions
DTC Descriptors
 DTC B2483: GPS Sensor Circuit Low
 DTC B2484: GPS Sensor Circuit Open
Circuit/System Description
The vehicle communication interface module (VCIM) receives information from a specific GPS antenna located on the outside of the vehicle. The GPS 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
|     •  | Ignition is in the RUN or ACC position.  | 
 
|     •  | Battery voltage is between 9-16 volts. | 
 
Conditions for Setting the DTC
B2483 00
The VCIM detects a short to ground on the GPS antenna signal circuit.
B2484 00
The VCIM detects an open/high resistance on the GPS 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 will clear once 50 consecutive malfunction-free ignition cycles have occurred. | 
 
Reference Information
Schematic Reference
OnStar Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
OnStar Description and Operation
Electrical Information Reference
Circuit/System Testing
-  Disconnect the harness connector at the radio antenna.
 
- Ignition OFF, test for less than 10 ohms between the terminal 4 outer shield and ground.
 
| ⇒ | If greater than the specified range, test the antenna coax shield for an open/high resistance. If the coax tests normal, replace the VCIM. | 
 
- Ignition ON, test the terminal 4 center terminal for 4.5-5.5 volts.
 
| ⇒ | If greater than the specified range, test the antenna coax center terminal for a short to voltage. If the coax tests normal, replace the VCIM. | 
 
| ⇒ | If less than the specified range, test the antenna coax center terminal for a short to ground or an open/high resistance. If the coax tests normal, replace the VCIM. | 
 
- If all circuits test normal, replace the antenna.
 
Repair Instructions
Perform the 
Diagnostic Repair Verification
 after completing the diagnostic procedure.