More then one way to do it, and one is the "correct" way. If done correctly you do not need to unplug anything because the functionality was fully disabled so the system doesn't need to be touched. The other method is to unplug the injector and remove all error fault paths related to that system. The later method is a hack but works most of the time.
But sometimes other computer in the car can still pick the signals up right? And what do you mean with a hack?
It would be very nice to have files where I do not need to disconnect anything since I am very bad with tools