The recall involves Siennas from the 2004, 2005, 2007, 2008 and 2009 models years.
Toyota said Thursday that the shift locking device can potentially be damaged. If that happens, the minivans can shift out of park even if the driver isn't depressing the brake pedal.
Toyota said it has gotten reports of 21 accidents and 2 injuries related to the problem.
Owners will be notified of the recall by mail. Dealers will replace the shift-lock device for free.