Castignetti said he cannot entirely explain the success of the Sentra, which is at the end of its model cycle and doubled its sales from March 2010. The Sentra will be redesigned for next year.
"That's a car that continues to surprise us by doing better at the end of its life cycle than it did at the beginning," Castignetti said. "I wish I had a good answer as to why that is."
Versa to Sentra?
Nissan has been offering incentives to buy the Sentra -- and other models as well, including the Versa, which dropped almost 20 percent from March 2010. Castignetti said some customers may have shifted from Versa to Sentra during the month, but admitted that explanation does not fully satisfy him.
Sales at Nissan North America's luxury brand Infiniti rose 14 percent in March. The brand sold 11,287 cars and trucks, up from 9,942 in the same month a year ago.
Infiniti's G sedan has been on a roll, boosting sales for months, and the recently updated QX56 SUV turned in a 30 percent sales gain for March.
Ben Poore, Infiniti Business Unit vice president, said the brand's heavy rotation of TV advertising during the NCAA men's basketball tournament in March helped boost Infiniti awareness. He noted that the NCAA tournament attracted record viewing audiences this year, and Infiniti's ad initiative would carry into April.
Poore and Castignetti said they had reduced incentives on their models in March from February levels.
Combined Nissan and Infiniti sales gave Nissan North America Inc. a 27 percent increase for March, with total sales of 121,141 vehicles.