Speed sensitive volume control
 

I have a 2012 G non nav.
I have an iphone and I connect it via usb
The problem that I am having is with the speed sensitive volume setting.
It acts erratically and will lower and raise volume for no reason.
I have tried every setting - and + as well as turning it off.
It does not do this when using the satellite, am or fm only with the iphone connected and playing music.
Is there a way to disable this feature?