I'm going to watch this post with great curiosity to read what others might have to say about your mysterious non-pairing issue! Your issue is far above my pay grade as I was merely delighted to discover the location of the Bluetooth Module in the car and retrieve the security code off of it! This, I discovered from a YouTube search and I'm wondering if perhaps the guy that posted that solution might be of some help to you?
Here's his link:
Maybe this will somehow help. . .Good luck and update when/if/how this gets resolved.