Some Pics
TCU - To the best of my knowledge installed as standard on all US cars, provides Phone and Bluetooth prep etc
Under the TCU bracket you might see another unit. The MULF-HI is needed for 6FL. There is also a "MULF-LOW" installed in some cars which would be in the same place.
If you do not have the MULF-HI and you need 6FL you will have to swop the unit out.
*** check the label ***
NOTE - There is no guarantee that you have anything under the TCU