From Page 2 of the diesel supplement to my 2013 F350 owner's manual -
POWER STROKE DIESEL ENGINE
Note: Your vehicle’s powertrain control systems can detect and store
information about vehicle modifications that increase horsepower and
torque output such as whether or not performance-enhancing powertrain
components commonly referred to as “performance chips” have been
used. This information cannot be erased and will stay in the system’s
memory even if the modification is removed. The information can be
retrieved by Ford Motor Company, Ford of Canada, and service and
repair facilities when servicing your vehicle. This information may be
used to determine if repairs will be covered by warranty.