Photo of 2015 Altima courtesy of Nissan.

Photo of 2015 Altima courtesy of Nissan.

Nissan's 2016 model-year lineup is already seeing a refreshed Titan and Maxima, as well as more modest updates for its van lineup. Nissan is also planning "significant refreshing" for the Altima mid-size sedan and Sentra compact car after only three years in their current generations.

Commercial fleets had added the Altima more frequently than the Sentra, which was the No. 7 compact car registered by fleets in 2013. The Altima was No. 4 among mid-size and full-size sedans that year, according to Automotive Fleet data.

Nissan introduced new generations of both vehicles in 2013. On Aug. 18, Nissan announced it would bring significant updates to these top-selling models for the 2016 model year. Details about the updates "will be announced shortly," according to a release.

The Altima entered its fifth generation with the 2013-MY with a sedan that was larger and weighed 120 pounds less. Nissan also dropped the 6-speed manual transmission, as well as trim levels 3.5 S and 3.5 SV.

The Sentra, first sold in the U.S. in 1982 as the Nissan Sunny, entered its seventh generation with a new 1.8-liter 16-valve DOHC inline-four that improved fuel economy to 39 mpg highway and 30 mpg city.