All FWD 1996 to 1999 Northstars either Oldsmobile or Cadillac run a Delco PCM with a SERV. NO. 16214848
All 1999 RWD run a Delphi PCM & SERV. NO. 9354896
Lyndon has the software to tune
In 2000 they repositioned the crank sensors and redesigned the notches on the crank. So the block and PCM have to match at this time
All 2000 to 2003 run the same PCM. It is the SIEMENS. They had several SERV. NO. but they all supersede to one number. The PCM in my hand is a 12562481 and I know it is not the latest and greatest number.
All 2004 and 2005 FWD used a Serv. NO. 12587465 PCM. I think the is a E22, but it is not GMLAN. This has Transmission functions
This is a link to some PCM type and Information on all GM PCM's
PCM Type & Information List