intermitant beeping stops

Our '06, with 127,000 miles, Prius about a month ago started to beep, not a seatbelt beep nor a back up beep, but a different beep. At first it was once in an evening and then it was once a mile until it was several beeps in a mile. Not only would it beep on the road, it would beep in the garage while off - a couple of beeps in 5 minutes while sitting in the garage. Now, a month after it started beeping, it has stopped. At no time were there other indicators,, dash lights nor smoke nor smells indicating any malfunction. The sound came from in front of the steering wheel in the dash.

I have to take it in to my dealer to satisfy the steering link recall next week and I had alerted the service people of the beep: but of course they had never heard of any thing like that.

Any one else have a beep episode lately?