The included adjustable four position switch allows you to adjust on-the-fly from Stock, +20 HP, +40 HP, or +60 HP. There is no ECM flash required. Instead the module receives the data from the ECM and optimizes the signal to the engine to improve both power and fuel efficiency. True Plug-and-Play connectivity means you won’t need to cut or splice any wires. Just connect the Heavy Duty Truck Edition module into your existing factory connectors.