How to troubleshoot NAV1 & COM1 issue on Garmin Diamond DA 40?
- JJessica ScottSep 9, 2025
To troubleshoot NAV1 & COM1 issue on your Garmin GPS, check the configuration settings for GIA1 and the PFD. Also, check the Ethernet interconnect from GIA1 to the PFD. You can switch GIA1 and GIA2 to verify the location of the problem: If the problem follows the unit, replace the defective unit. If the problem persists, replace the defective PFD.













