I followed this guide to code to FTM and it worked fine.
https://www.e90post.com/forums/showthread.php?t=1495676
my RDC module also had completely inexplicable corrosion on it's power pins.
I like the FTM as now I can just swap wheels/tires on a whim and not have TPMS units and all that jazz to install/service.
it does work. needs about 5psi of pressure difference to know one is low.
Is not a substitute for checking tire pressures, as it just compares rolling diameter between tires to determine if one is low.