My P4 with tech package beeps 3 tones, usually when I'm entering a parking lot. I didn't purchase the Tech package with options and I don't have the parking assist. Sounds like it's coming from the drivers side and there's indications or warnings anywhere on the displays or the HUD.
I should have called it a 3 tone chime. On the highway I never hear a BSM chime. It happens in a parking lot going 2 mph. My wife heard on the road while slowing down at an intersection.