Intermitent Beeping from ECM

[gphydro]

After operating the boat for a few minutes, the ECM alarm starts beeping. If I stop and restart, the beeping will stop for a few minutes then return. I have disconnected the engine water temp and low oil pressure switches with no change. All the guages are in the normal operating ranges. I scanned the engine with an infared thermometer and did not find any high temperatures. The boat is running fine but the beeping is unnerving. Could it be a fault code? Or the transmission high temp switch(where is it?)? Thanks

[electricjohn]

That's the only two other things it could be, or a ground fault on the wire from the beeper to the ECM. The ECM actually grounds (completes) the beeper circuit.

[gphydro]

After having read about the knock sensor possibly being the problem, I located where the knock sensor was located, mid-engine, right side when facing aft. I removed the plastic side panel to have access to that side of the engine, found the sensor, then found the wire to the sensor in the bilge. I cleaned it, plugged it back on and no more beeping. I have used the boat several times, and no issues or beeping. So much for paying to have the boat winterized then summerized!!