Unfortunately, you are probably correct. The warranty manual basically says even doing any repair can void your warranty. That can mean, change an air filter.If you over or under tighten your lug nuts, you lose your warranty!!
Yep, I would think with a tune they could void it pretty easy... other things like performing your own routine maintenance would be much less likely.The problem with a tune is it adjusts all the factory set engine and transmission calibrations. They set the A/F ratio and everything. Ford will manipulate an argument to say the tune did void your warranty because the reprogramming changed "x" where the Ford manufacturers produced "x".
Since the computer controls everything and the tune reprograms the computer, an argument would be made. It would come down to court where ford has the lawyers and money.
You are absolutely correct. In fact, as I recall, the manufacturer is suppose to prove the modification actually caused the problem (i.e. Incorrectly tightening your lug nuts would have absolutely nothing to blowing your engine...but if you lost a wheel and subsequently damaged your suspension, they could have a good case...).An aftermarket item cannot automatically void the warranty, the Magnuson-Moss Act makes sure of that. However, I would suspect Ford could make a good argument that a tune caused engine problems if you had a tune and then had engine problems. Performing your own maintenance, such as oil changes, etc. and not using Ford (or any other manufacturers) parts cannot void your warranty unless the manufacturer can prove you were inept at performing the tasks, or the parts were so inferior that they somehow caused damage and/or failure.