so i have a 3gs with the most recent update. and out of no where whenever i plug my phone into my car the car says there is no songs on the ipod. so i cant control song selection or volume by the car. i have to control it all on the iphone. yet the iphone works everywhere else. just not in infinitis anymore. i know this because it didnt work in my car or two other cars i tried at my local infiniti dealer. i took it to apple they said they couldnt find anything wrong because it works on everything they used. apple or not. which is what im finding too on all my devices. wtf is up. this started out of no where.

 

WOW!

I can't be of any help but what firmware version are you running?
My wife has a iPhone 3GS and it has been working perfectly and I have a new Nano that works fine too...

Strange.

 

As a last resort, maybe you could try doing a complete restore of the iPhone to factory settings:
Backing up, updating, and restoring your iPhone and iPod touch software

Be sure to back up all of your apps, contacts, songs, emails, videos, etc before doing this because they will all be erased from the phone.