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Pinpoint Test B: Navigation System Does Not Operate Correctly - No Global Positioning System (GPS) Antenna Signal

WARNING: This page is about a different car, the 2005 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: The vehicle must be driven outside of any enclosed structure to an area that is unobstructed by trees, tall buildings, and bridges.
  1. B1 CHECK THE RECORDED DTCS FROM THE NAVIGATION SYSTEM MODULE 
    • Use the recorded results from the navigation system module self-test.
    • Are any DTCs recorded? 
  2. B2 CHECK THE GPS ANTENNA FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: GPS Antenna.
    • Measure the resistance between the GPS antenna center conductor pin, component side and the GPS antenna shield, component side.
      Fig 1: Measuring Resistance Between GPS Antenna Center Conductor Pin And GPS Antenna Shield
      G03931236Courtesy of FORD MOTOR CO.
    • Is the resistance between 80 and 125 ohms? 
  3. B3 CHECK THE COAXIAL CABLE CENTER CONDUCTOR FOR A SHORT TO GROUND 
    • Disconnect: Navigation System Module GPS Antenna.
    • Measure the resistance between the navigation system module GPS antenna coaxial cable center conductor pin, harness side and ground.
      Fig 2: Measuring Resistance Between Navigation System Module GPS Antenna Coaxial Cable Center Conductor Pin And Ground
      G03931237Courtesy of FORD MOTOR CO.
    • Is the resistance greater than 10,000 ohms? 
    • Yes  : GO to  B4.
    • No  : INSTALL a new antenna coaxial cable. CLEAR the DTCs. REPEAT the self-test.
  4. B4 CHECK THE COAXIAL CABLE CENTER CONDUCTOR FOR AN OPEN 
    • Measure the resistance between the GPS antenna coaxial cable center conductor pin, harness side and the navigation system module GPS antenna coaxial cable center conductor pin, harness side.
      Fig 3: Measuring Resistance Between GPS Antenna Coaxial Cable Center Conductor Pin and Navigation System Module GPS Antenna Coaxial Cable Center Conductor Pin
      G03999131Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : GO to  B5.
    • No  : INSTALL a new antenna coaxial cable. CLEAR the DTCs. REPEAT the self-test.
  5. B5 CHECK THE COAXIAL CABLE SHIELD FOR AN OPEN 
    • Measure the resistance between the GPS antenna coaxial cable shield, harness side and the navigation system module GPS antenna coaxial cable shield, harness side.
      Fig 4: Measuring Resistance Between GPS Antenna Coaxial Cable Shield, Harness Side And Navigation System Module GPS Antenna Coaxial Cable Shield, Harness Side
      G03999132Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes  : GO to  B9.
    • No  : INSTALL a new antenna coaxial cable. CLEAR the DTCs. REPEAT the self-test.
  6. B6 CHECK THE NAVIGATION SYSTEM 
    • Move the vehicle outside of any enclosed structure to an area that is unobstructed by trees, tall buildings, and bridges.
    • Turn the audio unit on.
    • Press the MAP button.
      Fig 5: Identifying Audio/Map/Navigation Buttons
      G03999133Courtesy of FORD MOTOR CO.
    • Monitor the GPS icon. 
      Fig 6: Monitoring GPS Icon
      G03931239Courtesy of FORD MOTOR CO.
    • Does the GPS icon disappear? 
    • Yes  : The system is operating correctly at this time.
    • No  : GO to  B7.
  7. B7 CHECK THE GPS SIGNAL STATUS 
    • Press and hold the AUDIO and MENU buttons for 5 seconds.
      Fig 7: Pressing AUDIO And MENU Buttons
      G03931231Courtesy of FORD MOTOR CO.
    • Press 917 Enter.
      Fig 8: Pressing 917 Enter
      G03931232Courtesy of FORD MOTOR CO.
    • Select Navigation Info.
      Fig 9: Selecting Navigation Diagnostics Info
      G03931233Courtesy of FORD MOTOR CO.
    • Select GPS Information.
      Fig 10: Selecting GPS Information
      G03931241Courtesy of FORD MOTOR CO.
      Fig 11: Checking GPS Signal
      G03931242Courtesy of FORD MOTOR CO.
    • After 10 minutes, does the ST (status) column of the GPS information display P (position) or T (tracking)? 
    • Yes  : The system is operating correctly at this time.
    • No  : GO to  B8.
  8. B8 SUBSTITUTE THE GPS ANTENNA 
    • Substitute a known good GPS antenna.
    • After 10 minutes, does the ST column of the GPS information display P or T? 
    • Yes  : INSTALL a new GPS antenna. REFER to (GPS) . CLEAR the DTCs. REPEAT the self-test.
    • No  : REINSTALL the original antenna. GO to  B9.
  9. B9 CHECK FOR CORRECT NAVIGATION SYSTEM MODULE OPERATION 
    • Disconnect all the navigation system module connectors.
    • Check for:
      • corrosion
      • pushed-out pins
    • Connect all the navigation system module connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    • Yes  : INSTALL a new navigation system module. REFER to NAVIGATION SYSTEM MODULE . CLEAR the DTCs. REPEAT the self-test.
    • No  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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