Recently I noticed my car is producing a constant high pitch noise coming from the radio unit. When I turn my car off and open the door, the noise continues for another minute or two. This started happening two days ago when the volume wouldn't increase for my Apple CarPlay and Bluetooth. I was able to fix those problems by removing the positive battery cable for 15 minutes, however, this high pitch noise remains. I have an appt with the service dept. at the dealership but they're not available until the 24th and over the phone, the person I spoke to said he's never heard of an issue like this so that's not exactly reassuring.

Has anyone else experienced this type of sound/issue? Attached is a video of the sound for reference.

 

Did you ever figure out what it was? Mine just started doing that tonight!