Hi,
I am posting this because I had a nightmare of a time going through this myself.
I lost the one and only key that I had to my 2010 Silverado. ( I know, I am an idiot)
These are the steps to program a master key that you will need to get from your dealer or other retailer.
My local Chevy dealer told me I had to have my truck towed to them so that they could fix it. After completing a little research, I completed this on my own and saved myself probably $250 in towing fees and a major headache and other fees at the dealer. Rule of thumb, do not always trust what the dealer tells you.
IF NO OTHER WORKING KEY FOR THE CAR IS AVAILABLE: 1.Put the newly cut Master key into the keyway and turn it to the ON (RUN) position. A "Security" indicator light on the dashboard will stay on for 10 minutes. 2. Within 1 minute after the indicator light goes off, turn the ignition to "OFF" then return to the ON (RUN) position. The indicator light again will stay on for 10 minutes. (DO NOT REMOVE THE KEY) 3. Again, within 1 minute after the indicator light goes off, turn the ignition to "OFF", then return to the ON (RUN) position. The indicator light again will stay on for 10 minutes. (DO NOT REMOVE THE KEY) 4. When the light goes off for the third time, the new key is programmed into the computer and will start the car. Remove the key and then re-insert it into the ignition lock and start the car. All previously stored codes will be erased. To stop the process at any time, simply remove the key and use an existing key to start the car.
HOW TO PROGRAM THIS KEY IF YOU HAVE ATLEAST ONE WORKING KEY
FOR CARS WHERE YOU WANT TO JUST CREATE A SPARE KEY: 1. Place an already programmed key in the keyway. 2. Cycle the ignition from OFF to ON (RUN) to OFF. 3. Within 15 seconds, insert the new, properly cut Transponder key in the ignition. Turn the key to ON (RUN) or START. The "Security" indicator light will go on and off. Turn the key "OFF". The key will now start the car. Repeat the second step for each new key to be programmed.