You can use another PCM.. Make sure though it is from a Tahoe, Suburban, not a van.. I can tell you from experience... I think the VATs??? need to be unlocked, but others will know that.. I have another PCM I bought from an Avalanche. It works fine. I do get a Battery light that flashes in the message center but there is nothing wrong. It all has to do with the options that an avalanche has, I guess..