Q: iphone 6s bluetooth Kenwood head unit

Last week I was happy to finally upgrade my trusty (never EVER given me any issues in 2 years of ownership) iPhone 5s to the new iPhone 6s.  I travel frequently for work, so I immediately tried to connect my phone to the head unit for hands-free calling.  It will connect initially, good for one call or good for one power cycle of the car, and then I have to unpair the device, search for it, and get it to connect before using the handsfree capability in my car.  This process, btw, takes up to 5 minutes each time.

This is absolutely irritating.  I have a very expensive aftermarket head unit in my car that worked flawlessly with the iPhone 5s.  I believe that the Bluetooth radio is somehow to blame because it will disconnect and not reconnect at random times when connected to other Bluetooth devices like speakers or headsets.  I have been searching online for answers and I have already done the settings, general, reset network to troubleshoot but after doing that several times, still no improvement.

The head unit is a DNX9990HD.  Thanks in advance for any advice or possible solutions.