Back in October when the first iPhone 5’s made it to users’ hands, there was a complaint on an Apple support community about the phone not being able to pair with the user’s car system via Bluetooth. In the months since, the thread has grown to 29 pages with a mix of complaints and solutions in the comments. The basic issue is that users cannot connect their iPhone to their car audio systems via Bluetooth, cannot connect to Bluetooth headsets or other Bluetooth devices. Mostly, this problem arises after users switch to an iPhone 5, which comes with iOS 6. But there are also some cases of the same problems happening for iPhone 4S. These are some solutions that have worked for the users:
Updating the car system: Most car audio systems may be using an older version of Bluetooth that is not compatible with the Bluetooth 4.0 standard that is incorporated in iOS 6 devices. In this case, talking to your car system manufacturer and getting a firmware update will resolve the issue. Apple has also issued an announcement stating that users will have to update their car software in order to pair it with AVRCP 1.4 Bluetooth in order to allow all features to function correctly.
Go back to the basics: As is true with a lot of smartphone functions, Bluetooth pairing is not as simple as it should be. A password should be entered on both devices before they can be paired. A lot of users are accustomed to their old iPhones just pairing automatically and may have forgotten the detailed steps for setting up a Bluetooth connection once again. The thread contains several comments with detailed set-up instructions to help with this.
Clear car device settings: In some cases, your car device may have memorized your old iPhone and may still be trying to pair with it, rather than sending a request to the new one. This can be worked out by erasing the memory of the system and then trying afresh.
Update phone OS: Sometimes it may not be the fault of your car at all, but of some bugs in the iOS 6. iOS 6.1 promises an answer to all these bugs and therefore an update may eliminate the pairing issues. The success of this step is debatable, going by the comments on the community page.