Originally Posted by PersonaNonGrata

You might have the "Limit" feature set. That's when there is a speed set in the OBC and it will beep whenever you've exceeded it. I don't believe there is any message that will appear in the display. It's a silliy feature I have never used.

If it were the cold winter season I'd suggest that it is the black ice warning chime that sounds when road temps drop to a certain temperature.

Consult your owner's manual.