2016 Yamaha 242 Limited SE "Gateway Comms Error"

[Kbeats103]

After shutting down my port engine post-flush (and prior to turning off the key or the batteries), I received the "Gateway Comms Error" on my Connext - exactly the same symptoms as Julian described in his post:
2016 242X connext "gateway comm error"

Symptoms:
1. "Gateway Comm Error" on Connext (won't clear and audibly alarms every 5 minutes)
2. No fuel tank level indication (instead of a %, it shows "NC")
3. No speed indication (shows "Err" instead)
4. Polk Audio system won't turn on nor connect to bluetooth
5. No power at the passenger USB connection (tried plugging in my iphone and it wouldn't charge)
6. All other systems normal (engines, throttle control, etc.)

I went through Julian's post and troubleshot the potential issues I learned about from that post; I've verified my batteries are supplying sufficient voltage and all connections are tight, the two 20a micro fuses are satisfactory, as is the 5a micro fuse in the battery locker fuse panel.

I ran the boat for a few hours yesterday just to get out on the water, and one unusual occurrence while underway is that this "Gateway Comms Error" cleared and all indications on the Connext screen were normal for about 1 minute, and then the error came back in and stayed in. This leads me to believe there is a connection that is loose or otherwise degraded than when connected for the brief period, made the system work properly.

Anyone else out there have this problem and able to determine what the gremlin was? I know Julian narrowed down his issue to the fuses described above. I've also read some of the forums that indicate the issue could be from the GPS and/or the port tachometer, so I'll search there too. Is there a wiring diagram out that shows what ties into the Gateway network? I have the tech manual for the boat, and while there are accurate tables that describe what wires are in various wiring harnesses, I haven't found a comprehensive wiring diagram that shows what is connect to what.

I'm taking a stab at troubleshooting the electrical systems myself before I try to find a dealer (I bought the boat used from a private seller), so I'll document what I find as I go. I'm just hoping someone out there can narrow down my search to save me some time!

Thanks everyone!

 

[Cambo]

How is your rear swim deck stereo control does the knob turn and push ? If not remove the rear speaker reach in and unplug the stereo remote it looks like you live near salt water and these units fail due to water intrusion they are tied into the system and could cause an error.

 

[Kbeats103]

Cambo - My swim deck remote unit looks crusty, as if salt water did degrade the exterior. And you are correct, I do boat in salt water. Up until this issue, however, the remote unit did work properly. The knob is free to rotate and does feel like it still has its pushbutton functionality. All other pushbuttons feel normal as well. No other obvious signs that would point to it being the problem. But I'll take any recommendation I can and will access it and disconnect it to see what happens.

Do you know if the system will still see an error or fault if certain components are disconnected (vice if they remain connected in a degraded condition)? For example, if I disconnect the entire Polk stereo head unit, would it result in the same "Gateway Comms Error"?

 

[Kbeats103]

End of season update: after the initial issue, I ended up completely disconnecting all wires to batteries. Charged batteries with smart charger. Cleaned battery post terminals. Cleaned all exposed metal on wire end fittings. Coated exposed metal with a light film of dielectric grease. Reassembled everything and ran the boat the rest of the season without ever getting that error again. I did get the "Drive Control - Check Engine Warning" on the starboard engine twice this season when slowing down from cruise - came in when throttles taken to neutral. Verified nothing jammed in buckets or nozzles, then turned everything off, secured batteries, and waited a few minutes before powering back up - cleared the warning each time. I believe the boat is really sensitive to voltage fluctuations - especially with batteries at lower starting voltages (per Connext, mine are typically 12.0-12.2 volts each time at cold startup). I’m planning on putting in new batteries this off season as my current batteries are 5 years old and I think the cause of these electrical faults. Any battery recommendations?