No NAV Data Available

[ncgrady2016]

I have NAVPILOT 300 with dual Garmin 943xsv units on an NMEA 2000 bus. The NAVPILOT receives Nav data and will start navigating and then intermittently lose the Nav data. I receive the “No NAV DATA AVAILABLE” error. It then regains the heading in about 5 seconds and continues until it happens again. Any ideas? I tried to change the source for the autopilot data with no help. I also use PG700 and GP330B GPS receiver. Thanks

 

[Johnny Electron]

I would recommend contacting Garmin and also ensuring you are running their newest firmware. It appears there is starting to be a trend of their units dropping Navigation data. https://furunousaforum.com/threads/garmin-1223xsv-with-navpilot-300.19873/

 

[ncgrady2016]

I have the latest firmware installed. Could the fact that I have two units be causing this? Collisions of the same data on the bus? Garmin does not have a way to control which PGNs are sent, it is automatic. I can confirm the 3 needed seem to be there

 

[Magnetron]

I have the latest firmware installed. Could the fact that I have two units be causing this? Collisions of the same data on the bus? Garmin does not have a way to control which PGNs are sent, it is automatic. I can confirm the 3 needed seem to be there

Since we're not Garmin experts here, we defer to Garmin support for the GPSMAP 943xsv or double check the owners manual. Your GPSMAP supports PGN129283 and 129284 which is your "NAV Data."

One thing that sometimes gets missed is conflicting position PGNs. For example if you have a secondary GPS position sensor like the GP330B, and the "Garmin Marine Network" both putting out the PGNs 129025, 129026, and 129029 than you have a device conflict. Either through the Garmin turn off those PGNs, or instance up the GPS receiver.

- Maggy