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Cummins 450C No Start (Data Link Inactive)

Posted: October 13th, 2025, 9:35 am
by trwestman
Tried to start my Starboard engine. Key On there were no lights on the display panel. Specifically I look for “Wait to Start”. Digital display turns on after system checks and says “all systems ok” even though no data is on the screen, then changes to “Data Link Inactive. The analog gauges for voltage indicate 13.5 volts and Fuel is 3/4. Oil and Temp gauges are constantly moving. Engine will crank strong but not start.
I’m Leaning toward a broken wire or dirty connector at this point but not sure where to start. Any thoughts out there?

Re: Cummins 450C No Start (Data Link Inactive)

Posted: October 13th, 2025, 1:35 pm
by KuyaJunGarage
Check the solenoid? Jump to 3:50 on this youtube link (good explanation)


I have the same boat 2000 506

Re: Cummins 450C No Start (Data Link Inactive)

Posted: October 13th, 2025, 2:00 pm
by trwestman
Thanks for that. I first need to check power at the ecm. Not sure how to do this. I have no signal output from the ecm. I wonder if the red fuse buttons might have something to do with this. The video references them when diagnosing.

Re: Cummins 450C No Start (Data Link Inactive)

Posted: October 14th, 2025, 8:17 am
by KuyaJunGarage
No problem, let me know what you find out. good luck trwestman

Re: Cummins 450C No Start (Data Link Inactive)

Posted: October 14th, 2025, 5:43 pm
by trwestman
I was able to check the fuel shut off solenoid. There was no power in or out. I was also able to get a wiring diagram from Cummins and check pin voltages. There are two circuits which are supposed to be 12V unswitched from the battery. Both were 0. In the diagram there are 10 amp fuses in both of those circuits. Can’t find them. Anyone have any ideas?

Re: Cummins 450C No Start (Data Link Inactive)

Posted: October 14th, 2025, 6:21 pm
by Viper
If you have an automatic marine engine shutdown system installed, they're known to cause starting issues when they fail or have poor connections. These are common systems on diesel applications so if you have this, check it before replacing a bunch of engine parts. Fireboy/Xintex is one brand but there are others. Looks something like this and the box is usually under/behind the helm...

Re: Cummins 450C No Start (Data Link Inactive)

Posted: October 15th, 2025, 8:37 am
by KuyaJunGarage
trwestman - did you check the voltage on the port solenoid engine? Im guessing they have 12volt.
Under the steering wheel there is a vent that you can remove, check the igniton cylinder