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.

Circuit Description

The global positioning system (GPS) antenna is connected to the navigation radio by a shielded coaxial cable. The antenna cable also provides a path for DC current for powering the GPS antenna.

Diagnostic Aids

The global positioning system (GPS) requires a clear line of sight to the sky to operate properly. In most cases the GPS will not have reception near tall buildings or inside structures.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Navigation System 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. Ignition OFF, disconnect the GPS antenna coax cable from the navigation radio.
  2. Ignition ON, test for 4.5-5.5 volts between the coax cable connection center conductor at the radio and ground.
  3. ⇒If not within the specified range, replace the radio.
  4. If all circuits test normal, replace the GPS antenna.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Electronic Navigation Antenna Replacement
    •  Control Module References for Radio replacement, setup, and programming