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 B2462: Global Positioning System (GPS) Antenna Malfunction

Circuit/System Description

The communication interface module (CIM) receives information from a specific navigation antenna located on the outside of the vehicle. The navigation antenna is connected to the CIM 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

    • The CIM detects a short to ground on the navigation antenna signal circuit.
    • The CIM 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 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 Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Disconnect the navigation antenna coax cable from the CIM.
  2. Ignition ON, test for 4.5-5.5 V between the CIM coax cable center conductor terminal at the module and ground.
  3. If not within the specified range, replace the CIM.
  4. Reconnect the coax cable to the CIM. Disconnect the coax cable from the navigation antenna.
  5. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
  6. If not within the specified range, replace the coax cable.
  7. If all circuits test normal, replace the navigation antenna.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Cellular and Navigation Antenna Assembly Replacement
    •  Control Module References for CIM replacement, setup, and programming