This is my point. Anyone can make a reasonable guess as to what is going on, but the fact is that Toyota has not publicly acknowledged the precise nature of the defect (and probably never will). Presumably, they are making changes to the part and testing before rolling out to the millions of customers affected. Given that this is part of the fueling system, it's not unreasonable to think that there might even be associated software changes required as a result of any hardware change. All of this to say that there is no path to an assured fix short of just waiting for Toyota to do it, on their timeline. Anyone who is concerned enough that they fear driving their vehicle in the meantime might consider asking their dealer to cover a rental car. I'm sure they won't volunteer to do so, but I heard of it happening with owners affected by the Takata airbag recall.