I have 06 496ho's, yesterday a few different times the alarm would go off on port motor...One time when idling, all gauges appeared normal, temp gauge was 145, oil pressure 30psi, fluids all full. The 1st time it happened was after putting in water and was idling for about 5 minutes. shut off and checked over all seemed good..Started and shut off a couple of times and alarm went off?
What are all the items the system monitors?
Any particular issues anyone has seen?

Thanks in advance!

Drive reservoir, most often overlooked.

Both drive tanks where 3/4 full.

Would a scan tool show the reason for the alarm?

Yes, I would get it scanned to eliminate the guess work.