My son called today while waiting in line to have the emissions tested on his 2012 Ford F-150. I had warned him to make sure he had put his truck back to the original ‘Factory Tune’ as opposed to the various other tunes to increase horsepower or to improve towing, he assured me had just before leaving his house… he failed the test. Long story short, within the last few weeks, he had to disconnect his battery, which dumped all of the computer data the Emission’s folks are looking for, so they sent him off to complete a driving list for his truck that should capture what is needed to pass. However, the truck MUST go back to the Factory Tune mode in order for this to happen. When he had disconnected his battery, he kept the custom tune active, so the computer ignored the data points necessary to fill in the parameters. I don’t have any vehicles that I’ve ‘tuned’ electronically, but if you happen to do so, be aware that if you lose your battery connection, you’ll likely need to restore your original factory setting for a several days/miles of normal driving (assuming you get up to highway speeds for some period of time) in order to fill in the computer blanks needed for emissions tests.