This is a loaded question. Under the Magnuson-Moss Warranty Act, the vehicle manufacturer can’t simply void your warranty for modifying or altering your vehicle. If there is a warranty claim, the vehicle manufacturer must prove that the aftermarket modification is what caused the failure. This means the burden of proof is on the vehicle manufacturer. You can learn more about the “Magnuson-Moss” Act by visiting this link: https://www.mlmlaw.com/library/guides/ftc/warranties/undermag.htm
Having said all that, installing a performance tune does require a vehicle to be in good operating condition and if it is not, a failure is more likely than if it were stock. You can rest assured that we have custom tuned thousands of Workhorse and Ford motor home engines over the last 15 years and have never had a reported engine failure due to our custom tuning.
Our custom tuning philosophy is to gain power and improve shifting while maintaining reliability. Compromising reliability for more power is not your goal or ours, so you can install our custom tuning with a very high level of confidence that you will not have issues and drive away happy with your purchase.