if you don't have Idrive the reset process is pretty confusing...that might be where your problem is.
turn your car on and use the BC button to go to the tire pressure option.
hit the BC once and then press and hold it until you get the actual reset dialog on your dash.
I spent weeks frustrated from the warning light and manually checking the tires until I figured this out
JB4 | H&R Front and Rear Sway bar | Front Strut Bar | MS8 | NBT, 6WA, PDC, 3AG Retrofit | Full M-Tech Bumpers | 335 Brakes | BC Coils