I have a Levante and when I connect my phone via bluetooth and make phone calls, it makes a humming noise in the background. I took it to the service center a second time and after testing they told that it is a problem with all Levante's and can't be fixed.
Is this a known issue that Levante customers need to live with?
When you are on a call try turning up the volume on your phone (can usually just use the side volume buttons). If the phone isn’t at max volume during the call you will get some unintended stereo system noise. Also, sometimes you cannot turn up the volume for the phone call before the call, so make sure you are adjusting it during a call.