(Corrects day lawsuit being filed to Tuesday, not Wednesday)
WASHINGTON, May 23 (Reuters) - The U.S. Justice Department plans to file a civil suit against Fiat Chrysler Automobiles NV on Tuesday after regulators accused the Italian-American automaker of using software to allow excess emissions in 104,000 diesel vehicles, two sources briefed on the matter said.
The lawsuit will label the undeclared auxiliary emissions controls "defeat devices" in 2014-2016 Fiat Chrysler vehicles, the sources said. Fiat Chrysler did not immediately comment.
Reporting by David Shepardson; Editing by Jeffrey Benkoe