GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B2483 00: GPS Sensor Circuit Low

DTC B2484 00: GPS Sensor Circuit Open

Circuit/System Description

The navigation antenna is connected to the vehicle communication interface module (VCIM) with a RG-174 coax cable. The VCIM polls the data from the navigation antenna once every second.

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

    • The VCIM does not detect a navigation signal.
    • The above conditions are present for greater than 1 second.

Action Taken When the DTC Sets

    • The OnStar® Call Center cannot locate the vehicle.
    • The OnStar® status LED turns red.

Conditions for Clearing the DTC

    • The VCIM detects the presence of a navigation antenna.
    • A history DTC clears after 50 malfunction-free ignition cycles.
    • The VCIM receives the clear DTC command from the scan tool.

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

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Verification

Observe that the cellular antenna and cellular antenna coupling assembly are not damaged.

If it is damaged, replace the cellular antenna.

Component Testing

Important:  Using a DMM to measure the resistance of the navigation antenna coax from the center conductor to the outer shield while the antenna is still connected will damage the navigation antenna.

Important: The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.

  1. Disconnect the navigation antenna coax connector from the navigation antenna.
  2. Test for infinite resistance between the center conductor of the coax to the metal outer shield.
  3. If not specified value, replace the navigation antenna coax.
  4. Test for less than 1 ohm resistance of navigation antenna coax connector from end to end.
  5. If not specified value, replace the navigation antenna coax.
  6. If cellular antenna coax tests normal, test or replace the VCIM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Radio Antenna Base Replacement
    •  Control Module References for VCIM replacement, setup, and programming