I found this on the BBC Garmin Forum and thought it might prevent some anxiety if it happens to one of us....

After fishing on Saturday, my 1222 beeped and said transducer overheat. 88 degree sunny day. It had been out of the water(stowed) for more than an hour and the transmit(pinging) was OFF.


Response..

Yes, it has overheat protection. I have observed this several times when stowed for 20+ minutes in the summer. Normal operation begins very soon after re-deployment and temperature drops.