Soft Alarm issue

[huntingwiley]

I have a Merc 350 MAG MPI that has a soft alarm. The boat runs great, I had the codes checked and it was alarming on the IAC. I replaced the IAC twice this past two weeks with brand new ones. Still alarming so I took it back and had the codes checked. Now they say it is throuhging random errors IAC being one of them. If I turn the key on with out starting the engine I still get the codes. I have checked all the connections I can find to sensors. Does anyone have any ideas on how to trouble shoot this?

[huntingwiley]

Just wanted to add I have also checked all the fluids.

[boatwakes]

What kind of alarm? Soft alarm is not a technical term so if you could describe it that would be great. Either 2 beeps every minute or one steady beep. Is power limited after the alarm? Does the engine have issues running? Worst case scenario is a new ECM but give as much detail as possible.

[huntingwiley]

Yes 2 beeps every minute. Boat runs great with no issues. I have checked all the siring connections I can find. I was thinking it may be to ECM but thought it would cause issue running also. Boat runs great and does not limit power.

[boatwakes]

What other codes popped up?

[huntingwiley]

IAC and Water pump were 2 I think there may have been a couple of others. I suspect the ECM is going. Just wondering if there was a way to test it before dropping $1600 on a new one.

Thanks,

Donnie