by SOReilly on Thu Mar 23, 2023 11:27 am
You will have to forgive me if this isn't 100% accurate but I will try provide you with some more information which you might find helpful.
NMEA 2000 is J1939 based with some marine specific additions made.
NMEA 2000 differs from more typical automotive can communications in that it is quite complex. message IDs can identify an origin device, a target device, message priority as well as what information is contained in the message.
A MoTeC dash or enclosed logger can transmit and receive 29bit ID CAN data and could be added to the NMEA 2000 bus.
You should be able to transmit the messages the Garmin display is expecting to see although without more information I can't say what results you will get.