It works with the current good key. Nothing happens with the new key. Also, I tried the first step first with the current key and was unable to initialize the 2nd key. When I tried the first step with the new key nothing happens which leads me to believe that key needs to have a certain amount of charge in the battery for it to work. I was able to get both keys to initialize but when I tested it afterwards the nothing happens with the new key.
'05 GMC Sierra SLT Z71 CCSB 4x4
'02 Regal LS
'00 740i Sport