My understanding is that sometime during or just before the 2011MY GM went from their being a documented process for the owner to the "relearn tool." Some 2011 owners manual give the manual method, others state the relearn tool. If you do a Google search you should be able to find the method that has the owner put the vehicle in the relearn mode (ignition on, press and hold both lock and unlock?). You then adjust the pressure starting at the front left, working your way around the vehicle in a clock wise manner. When the horn honks, you move to the next tire.
I don't know if this works with say a 2012 or 2013. I recently rotated my tires and haven't gotten a chance to try to do it myself yet to see if it was still programed in my 2011. When I was getting the oil changed on my Cruze the dealer acted if I brought the van in they would relearn them for free.
