DaimlerChrysler AG's Chrysler Group is working to resolve software glitches slowing production at a U.S. plant key to its ability to introduce a record 10 new car and truck models this year.

The Belvidere, Ill., plant's output of the new Dodge Caliber compact sedan hasn't met Chrysler's goals since assembly started Jan. 3, Frank Ewasyshyn, executive vice president of manufacturing, said Monday in an interview. The production targets aren't public, spokeswoman Michele Tinson said.

The slowdown limits dealers' supplies of the Caliber, contributing to a 40% drop in sales in July from June. Chrysler spent $420 million renovating the factory and equipping it with robots to make the Caliber and two small Jeep SUVs as part of the automaker's 2006 new-model push.

"This is the biggest year for us," Ewasyshyn said. "And Belvidere is the most complicated of the plants. It's been set up to run three vehicles and to pilot a fourth."