Toyota’s heavy-duty trucking unit was fined $1.6 billion on Wednesday over fraudulent emissions testing and other violations.

Hino Motors, a Toyota subsidiary, will plead guilty to conspiracy charges and pay penalties for deceiving regulators about its diesel engines, the E.P.A. said.

A Toyota subsidiary has agreed to pay more than $1.6 billion and plead guilty for violations related to the submission of false and fraudulent engine emission testing and fuel consumption data to regulators and the illicit smuggling of engines into the United States.