Hypertech 83004 HyperPAC 2001-2005 Chevrolet/GMC Silverado/Sierra Pickup 2500/2500HD/3500 Allows to power tune your vehicle for more horsepower and torque Plugs into your diagnostic port and collects all the necessary data from your vehicle Evaluates vehicle performance with unrivaled accuracy Monitors, displays and clears diagnostic trouble codes Lifetime Warranty