Just a guess, but check on the back side of the fender liner in the wheel wells. This is where it is on our 2008 328i.

Can I ask what your issue is, and what can be done by the decoding you intend to do? How do you decode?

I ask because my TPMS is giving a malfunction warning daily, I believe one or more batteries in my wheel mounted sensors are dying. The warning will appear for 5 secs and then go away.
I am actually bringing it into the dealer tomorrow so not sure I will see your reply before then...