When you change anything except the diognostic codes the programer is VIN locked to the vehicle and cannot be used to program another until the stock programing is loaded back into first rig. You can check and reset codes on multiple trucks but only tune 1 per tuner. Thats how mine works .
Mike
P. S. The tool hooks to the Diognostics port under the dash, you pick the mods you want,upload them, then un hook the tool. Nothing stays hooked to the truck but the software in the ECM.