The Volkswagen RNS 315 Navigation has a builtin Bluetooth carkit which is disabled by default. I am not sure why, I presume this is done because VW also sells carkits that integrate into the MFD.

The builtin carkit can be enabled using VCDS like this:


First go to Select Control Module:


Then select 37-Navigation:


Then select Coding – 07:


The Bluetooth module is in Byte 3, Bit 5 and is indeed disabled:


Remove the checkbox to enable it:


Click Exit and then Do It!

The Carkit is available under the Phone Button:


Multifunction Steering Wheel and Streaming music over Bluetooth works. There is no integration into the MFD/FIS.

Note that, if not already present, you need to install a microphone.