If it is NMEA 2000 compliant there should be a connector on the engine control computer that provides a NMEA 2000 output. I saw on an Austrailan website https://www.outbackmarine.com.au/Yan...ace-Cable.6218
a cable that may or not be for your motor.
Yes, you would have to run a new cable forward, but you can use shielded twisted pair signal cable (WM carries in some stores) and splice the connectors on either end. I bought a Yamaha cable a couple years ago to do the same thing and decided after I saw what it did, I could just as easily have spliced directly into the motor wiring behind the Yamaha connector and saved $100.