Chrysler Group LLC said Friday that it will add nearly 900 jobs at a factory in suburban Detroit and spare it from closure. The decision is a show of optimism that consumers will embrace the company’s refurbished midsize sedans.

The jobs will staff a second shift at Chrysler’s assembly plant in Sterling Heights, Mich., just north of Detroit, which makes the slow-selling Dodge Avenger and Chrysler Sebring midsize sedans.

In the fall, the company plans to start selling redesigned versions of the cars. The second shift will begin in the first quarter of next year, Chrysler said.

Chrysler CEO Sergio Marchionne told reporters that the Sterling Heights factory will stay open beyond its planned closing date in 2012. In addition to the updated Sebring and Avenger, the plant will get a new  midsize Chrysler on a new platform, Marchionne said.

Companies that make parts for the Sebring and Avenger, and the Sebring convertible, which also is built at the plant, are expected to add 500 jobs.

Marchionne said the additional jobs at Sterling Heights would be a combination of laid-off workers from other factories and new hires.

Through June, Chrysler sold just over 42,000 Sebrings and Avengers combined. But that was far behind the 154,000 midsize Camrys sold by Toyota Motor Corp. The Camry is the top-selling car in the U.S.

The Sterling Heights plant employs 1,270 workers on one shift.