I have found that with my pioner nav/bluetooth head unit that when a call comes in the it will not let you answer the phone on the radio or the headset its self. also i have found that after you call someone the head unit loses all control of the iphone and you can not change songs are anything. the way i get pass this is i switch the source to cd or sat radio then back to ipod and it works after doing that a few times you are able tochange songs then all if that does work you have to unplug and replug the iphone a few times. if i find anymore bus i will let you all know. P.S. sorry for grammar and spelling at work and typing really fast.