Navistar is recalling certain model year 2012-2013 IC Bus brand model 1300FBC, CE, HC, and RE buses; model year 2011-2013 International brand model Durastar, model year 2013 International brand Workstar trucks; model year 2013 Holiday Rambler brand model Ambassador and Endeavor vehicles; and model year 2013 Monaco brand model Diplomat and Knight vehicles. These vehicles were manufactured August 5, 2010 through September 6, 2012 and are equipped with certain 2011-2013 model year I-6 engines with feature codes 12NUK, 12NUL, 12NUM, 12NUN, 12NUP, 12NUR, 12NUS, 12NUT, 12NUU, 12NUV, 12NUX, 12NUY and 12NUZ. The injection pressure regulator (IPR) harness wire may break due to vibrational damage. This could cause an unexpected shut down of the engine.