By far and away the most frequently asked question when it comes to performance tuning of a given vehicle's Powertrain Control Module (PCM) or Engine Control Unit (ECU) is "will this void my warranty?" The short answer is yes, unequivocally and absolutely yes. Performance software tuning of your vehicle's computer will practically always void and Powertrain Warranty that your car or truck may or may not have. "But Stage 3," you say, "what about the Magnusson-Moss Warranty Act, running the vehicle through a drive cycle before I go into the dealer, or running down my battery to hide my tune?" There are some ways where you're still protected and ways that you can
possibly hide a performance tune from the prying eyes of Ford and your dealership. So the long answer to the initial question is "yes, but..." The fact is that the whole tuning/warranty situation is pretty sticky and complex, but there is a good reason that we at Stage 3 tell you that your warranty will
definitely be voided while the other guys beat around the bush or even lie through their teeth: we're looking out for you and your vehicle's best interest.
First, what does it actually mean when a "warranty is voided" by a tune. Well, your car or truck is covered by a manufacturer's warranty for basically every single component on your vehicle of choice. The specific warranty in question is your vehicle's Powertrain Warranty covering your engine, transmission, driveline, and their various components. When a warranty is "voided", it's specifically related to your vehicle's Powertrain and its related components. Meaning if you tune your vehicle and your window regulator goes out, your window regulator would still be replaced under warranty, given that it's not a system that's effected by a tune. So, when we say your vehicle's warranty is voided by a tune, it doesn't mean that Ford and your dealership will completely kick you to the curb. They just won't cover any Powertrain-related repair of replacement if they discover that your vehicle has a performance tune in it or has ran performance tuning in the past.
Now, you may hear something or other about being protected by the
Magnusson-Moss Warranty Act of 1975, which you technically are, since the Act requires a burden of proof from the manufacturer or dealer that a particular aftermarket part, accessory, or tune led to an engine failure or other issue. That being said, Ford and dealerships have much more money and a much larger legal team than you, and a drawn-out court battle with a judge that may or may not understand some of the finer points of the aftermarket or tuning will more than likely cost you more than new motor and still leave you footing the bill for full crate engine or long block if something catastrophic did in fact occur. So, while you're technically "protected" to some extent, the real-world practical issues leave a lot to be desired. Still, if you put a tune in your vehicle, but have a problem with something that is totally unrelated to the tune or powertrain (i.e. your window regulator, door locks, A/C, power steering, etc.), then those repairs would be covered.