2015 Lexus IS 350 sound doesn't come out of speakers when iPhone is connected

Sound not coming out from the speakers while it connected with Iphone

Which sound? iPhone sound? Radio sound? Engine sound? Key left in the ignition sound? Road sound?

Press the aux button if you have one.

And check to be sure the iphone volume is turned up.

I’ve noticed that the GPS volume (iPhone) and radio volume are controlled by the same knob, but they are not the same level. That is, the radio might be just fine, but the GPS volume is way too low. I found that adjusting the volume while GPS Lady is talking controls the GPS volume, but doesn’t affect the radio volume.