Validating PIDs

[azzhauler]

When validating PIDs, what determines which ones are available? I'm having an issue with an 12200411 pcm that I have swaped into my 98 Sierra using the calibration/os from a 01 Express van, as quite a few others have. On mine I'm only getting 44 PIDs including the external ones to select from. I also noticed that when I check the onboard modules, the list is empty. Not sure if those are related, but it seems to make sense. Any ideas on why this is?

[GAMEOVER]

The Vin# determines which one's are available I think, not 100% positive though...