I think I'm hearing a very faint chime (ping) in my "new to me" 2008 SL550. Not the kind of chime that is obvious or indicates some direct aspect of the car's performance. From what I can tell, it happens randomly, while driving. I usually hear it at slower speeds ie: driving through town. Maybe coming from behind drivers seat?

Thanks for any assistance/thinking on this.

So...I have those randomly in an older SL55. I stare at the display while chanting "no error code". Sometimes it's the proximity warning. Sometimes it's because it's hot out.
Repeat after me "no error code". Also you posted in the wrong forum, but anyway.