I can speak for GM but likely the same for all the big three. When it comes to major powertrain warranty claims its not a dealer call (regardless of how tight you are with them). GM corporate will request an ECM snapshot. So if your CP4 takes a dump and takes out the entire fuel system just make sure you have $10-12k on hand to cover the cost because corporate will deny your warranty. Now if you power window does out that's a different story and why I said a programmer will void your POWERTRAIN warranty, not bumper-to-bumper warranty.