Note: This is the same for many GM vehicles.
Sit in the driver’s seat. Insert the key into the ignition but don’t turn it. Push and hold the “Lock” button on the door. Continue to hold it. Turn the key to on, off, and then back to on, rapidly. Doing this too slowly will cancel the programming procedure. Release the “Lock” button. The doors will sound. The remote is ready to be programmed. Push and hold “Unlock” and “Lock” on the remote for 20 seconds. The remote is programmed to the vehicle.