Cold Weather Diesel Reliability Act of 2026

This bill requires the Environmental Protection Agency (EPA) to let manufacturers of certain diesel vehicles and equipment temporarily or permanently disable engine power-reduction or shutdown features that are triggered by emissions control problems in cold weather.

Sec. 2, Definitions: Defines key terms. 'Administrator' means the EPA Administrator. 'Agricultural equipment' includes nonroad diesel farm machinery like tractors and combines, but not highway vehicles. 'Covered manufacturer' is the maker of a covered vehicle or its engine. 'Covered vehicle' means an on-highway diesel vehicle or nonroad diesel equipment.

Sec. 3, Diesel engine derate relief: Within 180 days, the EPA must change its rules to let manufacturers temporarily disable engine derate or shutdown functions triggered by emissions faults when it is 20 degrees Fahrenheit or below. Only the manufacturer can do this, and the engine must return to normal operation above 20 degrees. Separately, the EPA must also let manufacturers permanently disable those functions on agricultural equipment and on vehicles primarily operated north of 59 degrees north latitude.

Sec. 4, Rule of construction: Nothing in this bill waives compliance with any emissions standard under the Clean Air Act.