NHTSA hasn't gone so far as to issue a recall in this particular case as its research into the problem is ongoing. Previously, investigators were only looking into Corolla and Matrix models produced in 2006, though the recent expansion indicates that the issue may be more widespread than previously believed.
Last we heard, Toyota was considering a voluntary fix for the problem, though since then nothing has come up in terms of a proposed solution from the carmaker. Back in March, NHTSA said that the problem doesn't pose any danger to drivers.
[Source: Associated Press]