Also on Wednesday, Fiat Chrysler Chief Executive Sergio Marchionne said the company will within several years stop producing the Chrysler 200 as well as the compact Dart sedan, and will look to outsource that output.

The Sterling Heights Assembly Plant has two shifts and has been periodically shut in the past few months, also because of slack demand as the U.S. automotive market shifts to SUVs and pickup trucks and away from passenger sedans.

In 2015, passenger cars accounted for 40 percent of sales in the U.S. automotive market, down from 44 percent in 2014 and 51 percent in 2012, according to industry consultant Autodata Corp.

General Motors Co and Ford Motor Co in 2015 also had some shutdowns of U.S. plants making passenger cars due to lack of demand. Ford last summer announced that it will move production of the Focus small car from a Detroit-area plant, and union sources said it was moving to lower-cost Mexico.

(Reporting by Bernie Woodall; Editing by Jonathan Oatis)

By Bernie Woodall