If you own a 2011 or newer 5.0 liter Mustang (or F-150), be advised that Ford is on the warpath in regards to modifications and vehicle warranty. Their latest TSB warns that modifications may exceed component design limits, resulting in component failure (and the associated loss of warranty coverage). The TSB tells dealers to be on the lookout for aftermarket modifications, ranging from reflashed ECUs through intakes, headers and exhausts. A flowchart in the TSB talks dealers through the repair process, with one ending option being “Initiate warranty cancellation process”.
While dealers are still obligated to prove that a modification caused the component failure under the Magnuson-Moss Warranty Act of 1975, modifying things like the ECU gives dealers a broad range of claims to deny. Reflash the ECU and hole a piston, and the repair won’t be covered by Ford. Reflash the ECU and have a shock absorber leak oil, and you should still be covered by your car’s warranty.
It’s not yet clear how dealers will interpret this TSB, but the tone of the bulletin sends a clear message. In the past, manufacturers were more tolerant of modifications, but many cars today are damn near optimized in stock form. If you opt to mod your car and exceed the specs for a component, don’t expect the manufacturer to replace it for free.
Source: Mustangs Daily