A "ding" chime when I accelerated my 2003 Kia Sorento?

Not sure if you will understand my question. These two days when I accelerated my Kia 2003 Sorento, I realized that sometimes there's a chime - it's only one "ding" (if you forget to take the key out or you forget to close the door, usually the chime is ding..ding..ding..which continues for about 7 or eight dings). No warning or indication light was on. It never happened before....Does anyone have some ideas? Thank you!