Nissan Division's monthly U.S. sales hit an all-time high in March, increasing 0.4 percent to 126,623 cars and trucks from March 2012. The brand's mid-sized Altima, in a rare achievement, passed the Toyota Camry to become the nation's best-selling car.
But while sales are rising, Nissan's growth in U.S. market share has slowed. Nissan closed 2012 with a 7.1 percent share of the U.S. market, down from 7.4 percent at the end of 2011.
The company had been steadily racking up share – up from 6 percent at the end of 2008.
Nissan Motor Co. has recently targeted a 10 percent market share for Nissan and the luxury Infiniti brand combined. It finished 2012 with a combined U.S. share of 7.9 percent, down from 8.2 percent for all of 2011.
Diaz was named CEO of the Ram brand in October 2009, and chief of Chrysler's Mexico operations in 2011. In Mexico, he was responsible for Chrysler, Jeep, Dodge and Ram brands.