Toyota is recalling certain model year 2006-2012 Lexus IS250 and IS350 vehicles manufactured August 23, 2005, through October 5, 2011; 2010-2012 Lexus IS250C and IS350C vehicles manufactured April 10, 2009, through October 6, 2011; and 2008-2011 Lexus IS-F vehicles manufactured December 14, 2007, through July 10, 2011. The nuts that fasten the wiper arms may be insufficiently torqued such that if the wiper arms are restricted by an external load, such as a buildup of heavy snow, one or both of the wipers may become inoperative.