iphone 5 will not pair with vehicle

My iPhone 5 will not pair with my vehicle. Other devices have no problem pairing, but the new iPhone will not. I have a Chevy Volt 2012 and I have talked to a Chevy Volt advisor, a Verizon Wireless customer service rep as well as an Apple customer service agent, with no results. I value using bluetooth while driving and must have this fixed. I may have to return the new phone.