325 workers at the Chrysler assembly plant in Belvidere have received temporary layoff notices.
The move comes as Chrysler and its parent company Fiat struggle to find buyers for the recently re-launched Dodge Dart.
The model, which is made in Belvidere, returned to the assembly line to much fanfare in 2012. The company added a third shift to the plant to coincide with the production.
But Dart sales in the U.S. have been disappointing, sliding 37 percent last month. Analysts say one of the problems is the incentives being offered by Chrysler for some of its other models. They say that seems to be steering customers away from the Dart when they visit dealerships.