Does the car have steering wheel controls?Its happened with two same units Same thing beep music down, music back up beep and repeat every 2 seconds
If both units had the same outcome, then the volume buttons on the steering wheel may be the issue. Try to open them for an inspection. They may have gotten dirty.Yes has steering controls
My thinking is that dirt holds moisture. Moisture from Armorall, sweat, soda or any other thing that may have gotten behind the rubber cover. You see this issue in remote controls, key fobs, window regulator controls, et cetera. I do not think both units would be looking for a folder. Maybe if the units have auto volume control, that may be the issue. If the microphones got damaged, they may be sending signal and the radio is adjusting accordingly. For this you must troubleshoot all theories.This sound is like a programmed sequence as though something is trying to look for something, i cant see being dirt controls, there is nothing in the menu either and turning TA and RDS does nothing