Quote Originally Posted by 87gmc
Question on the upgrading my OS.


I have a 99 5.3L truck. With commercial version I can upgrade it to a 2004 O.S. and just use a bin from that year? or exactly how does it work?
You can only go as late as GM went with that PCM, 2004 used a different PCM, as did 2003 trucks.
For your 5.3L truck I think 2002 is as late as you can go.

I've just finished off the 2002 O.S's and they should be posted up for download in about 12hrs time (it's midnight here!!).

Cheers,
Ross