Garmin 430 will not couple with Garmin 396 in the Aviation In mode

SOURCE: I have a Garmin 396

I recommend either resetting the device or update the software. You can find software downloDepending on which model of Garmin GPS unit you’re using, thefollowing routine can reset the Garmin device to original factoryloaded settings, or bring up the Maintenance Mode with access to SystemInformation and View Diagnostics screen, where users can see variouslogs, and of course, clear all user data (reset to factory defaults) orclear Waypoints.
In order to reset Garmin device or enter into maintenance mode, perform one of the following procedures:
Power off Garmin unit. Press on continuously the uppertop left corner of screen and then power on the unit by pressing onceon the Power button. You should be prompted to clear all user data, orasked if do you really want to start up in maintenance mode. Press“Yes” to reset (warning: all data will be erased and lost,so backup before proceeding) or enter maintenance mode.
Hack above works on Garmin Nuvi 660, 680 series.
Turn off Garmin device. Press down on bottom rightcorner of the touchscreen, and then power on the GPS unit. You shouldbe prompted whether do you really want to erase all user data, or askedif do you really want to start up in maintenance mode. Press“Yes” to reset (warning: all data will be erased and lost,so backup before proceeding) or enter maintenance mode.
Trick above works on Garmin nuvi 200, 250, 360 750, 760 series unit.In fact, there is a video demo by user of Garmin Nuvi 360 on how toperform the hidden reset function.

Note: If entering maintenance mode, it’s also possible to perform master reset by selecting clear user data option.
Once the device has been hard reset, user have to perform the set upprocedure again upon start up. Note that erase user data command onlydelete data in the Garmin unit’s memory that isn’taccessible to the user when the unit is connected to computer. Thecommand does not erase .gpi or .gpx files loaded (if your .gpx filescontain any waypoints then they will automatically be imported intoFavorites), nor will delete any MP3 music, JPG photos or any otherfiles that have been stored on the GPS memory card.
Once the Garmin GPS unit is reseted, remember to place the deviceoutside where there is a clear unobstructed view of the sky for 15– 30 minutes in order for it to requires fix to GPS satellites.
Unfortunately, even if you perform master reset on Garmin GPS unit,it does not reset Garmin Lock security feature, which password-protectmost Garmin electronic devices to deter theft. If you forget the PIN orpassword unlock code to unlock the Garmin unit, the best solution is tobring it to Garmin to get unlocked. “Secure Location” doesnot unlock a locked Garmin unit either as it’s only a temporaryfix as when it’s turn on outside the security location, thedevice is locked again.
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