I've been looking at different times for my 2016 GT. Do the tuners flash the stock ECM and void the warranty or do they have to be plugged in every time I drive to reflash?

 

Once you flash the new tune that is what will be on the ECU until you flash it again.


And if you tune the car, and then have any problem that can be related to the tune as A cause, then Ford will not warranty the work. Ford warranties the car that Ford built; once you change the tune that is no longer the car that Ford built. That would be just like changing your audio head unit and expecting Ford to cover it if it failed. (note it is A probable cause and not necessarily the same as THE probable cause as the standard of proof)


And someone next will chime in saying, "Magnsuson Moss Warranty Act requires Ford to prove the tune caused it". And while that is true, all that Ford has to do is say, "we investigated it and determined the after market tune caused the problem". They are then done with their proofs and the burden shifts to the consumer to: start a lawsuit, hire experts to prove that the trouble was not caused by the tune but is in fact a manufacturer defect, while Ford has deeper pockets and more engineers that have spent time studying the car.



And yes, Ford can tell if the tune has been reflashed because markers are left in the ECU. There are also other signs that they look for regarding aftermarket modifications.

 

Yes but they are also not dumb about it. If it's an unrelated system, most dealers won't waste their time trying to argue a tune is at fault or some other part that's not related is at fault. But, If you have driveability concerns like hesitation, surging, etc or something engine (heads, crank, block, etc) gets damaged, they will blame it on the tune.

Remember the #8 cylinder problems with the 2011/2012? Ford eventually admitted it was a build problem (not of their own volition) but not before they released a Service Bulletin about denying warranty work for any cars with a #8 failure that had a tune in it or certain mods. The problem was that under normal Ford parameters the problem was not as prevalent. With a tune that advanced timing and in some cases leaned out the AF, it created extra heat that exacerbated the problem. Some of the aftermarket tuners modified their tunes after this happened to help prevent their tunes from causing issues but, it was already too late, Ford had the bulletin in place. I think ONE person from this forum had their engine or head replaced even though they had a tune because they were able to prove through documentation that the problem existed before the tune.

https://latemodel.cachefly.net/downl...sb11-07-07.pdf

it took a third party to step in and expose the problem. After that, Ford had no choice but to openly admit it was a problem.