The Chevrolet Silverado and its mechanically identical twin, the GMC Sierra is a series of full-size pickup trucks manufactured by General Motors and introduced in 1998. Some model years of the GMC Sierra have keyless entry remote fob smart keys that are onboard programmable, meaning a person can program the keyless entry remote fob smart key with no special equipment other than the keyless entry remote fob smart key programming instructions. However, other model years of the GMC Sierra are not onboard programmable and require special equipment in order to program the keyless entry remote fob smart key.