Technically deleting the DPF voids your factory warranty. However, depending on the dealership; getting warranty work usually isn't a problem. The majority of dealers know that deleting the DPF is the best thing you can do to increase fuel mileage and improve reliability. They also want to get paid by the manufacture for the warranty work. To be honest the main reason you need a warranty is because of all the emission components. If the DPF has been removed you probably wont be visiting the dealer anytime soon. Our best advice is to call the dealer beforehand and inquire about warranty work on a truck that has been deleted.