I checked before opening works. Great came with easy to follow. Instructions only took a few minutes to program going to order another one. Compré un 2009 cts and one of the fobs was so dirty and worn out. It was disgusting. I bought this fob and in the box it has a card with a youtube link that shows you how to program it very easy to do. Range is about the same as the oem as well. Only way to tell it from the oem is that it does not have the cadillac emblem on the back. In summary, easy to program works as intended. It is a great price, but instead of opening all four doors, it opens three and my trunk and the door. It does not open is my drivers. One Music worked perfectly for my 2008 cadillac cts. I programmed two during the same session and they both have the same code. No more scratching door with keys came with instructions, so i had it working in less than three minutes. Key fob was easily programmed and works like a charm with my 09 cadillac cts isn’t, quite as sturdy feeling as the original but that’s to be expected and, Claro, no cadillac logo. En la parte de atrás. The key fob arrived as promised and was easy to program. For my 2008 cts, Sin embargo, after programming, the new fob, i found that my wife’s fob no longer worked.