2004 Honda 130 alarm buzzer when I turn key

Buzzer starts when I turn key to on before engine even starts. Started yesterday when idling, came home and still doing it today. When I turn key to on, All other lights flash for two secs and Alt stays on. I can start motor and all lights go off except green oil light. Engine runs fine. I've disconnected trim sensor under cowl, confirmed oil is good, drained water separator on engine. I've tried to pull ECM codes by jumping red connector under cowl, but Ecm light just stays lit when I turn key, it doesn't flash.

im stumped, any thoughts.

Is it a solid buzzer or on and off buzzer?

If a solid buzzer, then you may have a ground on the yellow/green lead from the engine. There may be corrosion buildup in one of the connectors, either at the engine on under the dash.

There is a possibility that it is a faulty ECM, but there are other things to check before that.

Mike

It is solid buzzer. I checked most of the connectors under the dash and under cowl but wasn't looking for yellow/green specifically. I'll go down and check that this week. Is there anything else I should test while there?

There is nothing else that I can think of at this time. The reason that I suggest looking for corrosion, etc. .... When you turn the key to on, you supply positive 12v to the horn. The horn is activated by a ground from the ECM on the yellow/green line. So, either the yellow/green has a ground on it due to something unknown or the ECM is actually, putting out a solid ground. Why...I do not know...could be faulty ECM or something else is fooling it.

I am hoping for the ground on the lead.

Mike