rusEFI console has commands for Bluetooth module initialization (see below), at the moment we do not have TunerStudio interface for Bluetooth module initialization.
https://github.com/rusefi/alphax-4chan is the most popular open source board with on-board bluetooth.
That's an open question see rusefi/rusefi#6197
JDY-33 seems to be the way to go Bluetooth in 2023. Yes, rusEFI supports JDY-33 initialization. Yes, 4chan comes with JDY-33. 2024 update rusefi/rusefi#5918 what a mess
On start, HC-06 accepts AT commands @ 9600.
the default pin is 1234
bluetooth_jdy 115200 alphax 1234
Which is just one the possibilities
// Usage: "bluetooth_hc06 <baud> <name> <pincode>"
// Example: "bluetooth_hc06 38400 rusefi 1234"
bluetooth_hc05 bluetooth_hc06 bluetooth_bk bluetooth_jdy
https://rusefi.com/forum/viewtopic.php?f=13&t=1999
A cool relevant Windows utility http://www.nirsoft.net