I am working on a 5120 hack on a 551r file and have am trying to find the missing maps.  I am working through all of this for thoroughness.  I am looking for KFDPVL in BGTEV.  I have disassembled the file, expanded all the code, cleaned up all the code, and entered all the ram values I know of.  I am seeing in the FR that mshfm_w and ps_w feed into KFDPVL and output to a function with pu_w that outputs pvl_w. 

And this is where I hit a wall.  I feel like Im starting to understand this but I dont know the structure of what Im looking for will look like.  At the same time, I tried to follow LAMFAW because I feel confident about my understanding of how it works and still ended up lost.  Can anyone help to point me in the right direction and give me an idea of what im looking for?  Id really like to understand the structure of it so I can work on my own in the future.

I think there's a list of RAM variables for 551R floating around here. And a full definition as well.

But back on subject: generally if you're looking for some specific function (and know the output variable) - you just go to that var address in RAM, press "x" for cross-references, sort by "R/W" and check writes to it. Some will usually be initialization (either by some constant, or from another var), others will lead you to the actual function.

Finding map references is a bit trickier.

That being said, AFAIK, there's no KFDPVL (and hence, pvl_w) in this binary.

I can tell you for certain the 5120 hack that is available here works as it's supposed to.  I use it on my car.  Keep in mind, this file uses base boost pid calibration, so the pid control is different than an s4 for example.  The damos for this binary is available, that is why variable listings, 5120 hacks etc are available as well.