I deleted the device form Sync (the truck), then shut the truck down all the way including accessory mode. Then, deleted the wifi network from my phone by selecting "forget this network" under Bluetooth devices. Next, I "Reset Network Settings" on the iPhone... and rebooted. I went back to my truck and started it, went through the normal pairing process, and it now works.
From what I read, it appears to be a problem when you have a new device, but keep the same phone name. So, if you're still having problems, change the name of your phone (under Settings>General>About>Name) from "iPhone" to "iPhone6" or something.