No Global Positioning System (GPS) Reception

No Global Positioning System (GPS) Reception

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)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 GPS antenna is powered through the same coaxial cable used to send signals to the navigation system. The antenna cable also provides a path for DC current for powering the GPS antenna.


Reference Information
Schematic Reference

Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Navigation System Description and Operation (Navigation System Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information


Circuit/System Testing

Important: 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.



1. Ignition OFF, disconnect the coax harness connectors at the navigation radio and the GPS antenna.
2. Test for less than 5 ohms of resistance between the two ends of the coax cable center conductor.

• If greater than the specified range, replace the GPS antenna coax cable.

3. Test for less than 5 ohms of resistance between the two ends of the coax cable outer shield.

• If greater than the specified range, replace the GPS antenna coax cable.

4. Test for infinite resistance between the coax center conductor and the outer shield.

• If less than the specified range, replace the GPS antenna coax cable.

5. Connect the coax harness connector at the navigation radio.
6. Ignition ON, test for 4.0- 5.5 volts between the coax center conductor and the outer shield.

• If not within the specified range, replace the navigation radio.

7. If all circuits test normal, replace the GPS antenna.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Global Positioning System (GPS) Antenna Replacement (Global Positioning System (GPS) Antenna Replacement)
* Control Module References (Programming and Relearning)for Navigation Radio replacement, setup, and programming