What does Preamble of Cold Weather Diesel Reliability Act of 2025 do?

This bill, formally titled 'To require the Administrator of the Environmental Protection Agency to authorize manufacturers of certain vehicles to suspend engine derate or shutdown functions in prolonged cold weather conditions, and for other purposes,' aims to address vehicle functionality in cold weather. The bill would require the Environmental Protection Agency (EPA) Administrator to authorize manufacturers to suspend engine derate or shutdown functions in prolonged cold weather conditions.

What does SHORT TITLE. of Cold Weather Diesel Reliability Act of 2025 do?

This bill is formally titled the Cold Weather Diesel Reliability Act of 2025.

What does FINDINGS. of Cold Weather Diesel Reliability Act of 2025 do?

This section establishes findings related to diesel vehicles. It notes that diesel vehicles are vital for critical transportation and emergency services, particularly in cold weather regions. The text highlights challenges with diesel exhaust fluid storage and system functionality in rural areas experiencing prolonged freezing conditions. It identifies risks associated with automatic engine shutdowns and power reductions caused by emissions control malfunctions in extreme cold. The findings state that emissions safeguards under the Clean Air Act were not intended to compromise human safety or critical mobility.

What does DEFINITIONS. of Cold Weather Diesel Reliability Act of 2025 do?

This section defines terms used within the Act. The term 'Administrator' refers to the Administrator of the Environmental Protection Agency. A 'covered manufacturer' is defined as the manufacturer of a covered vehicle or engine, as defined in section 216 of the Clean Air Act. A 'covered vehicle' is defined as an on-highway diesel vehicle or nonroad diesel equipment.

What does DIESEL ENGINE EMISSIONS RELIEF IN COLD WEATHER REGIONS. of Cold Weather Diesel Reliability Act of 2025 do?

This section addresses diesel engine emissions relief in cold weather regions. The Administrator is directed to revise regulations under the Clean Air Act to allow covered manufacturers to suspend engine derate or shutdown functions triggered by emissions control system faults when ambient temperatures are at or below zero degrees Centigrade. The suspension of these functions is conditional on the engine returning to normal operation when temperatures rise above zero degrees Centigrade and the continued maximum engine performance being necessary to prevent occupational danger, equipment failure, or loss of essential transportation functionality. The Administrator must also revise regulations to grant a year-round exemption from diesel exhaust fluid system requirements for covered vehicles operating north of 59 degrees north latitude or experiencing conditions making diesel exhaust fluid use impractical. This exemption includes relief from engine derate or shutdown functions triggered by diesel exhaust fluid system issues.

What does RULE OF CONSTRUCTION. of Cold Weather Diesel Reliability Act of 2025 do?

This section establishes a rule of construction regarding compliance with emissions standards. The Act does not waive compliance with the Clean Air Act. Exceptions to this non-waiver exist for the temporary cold-weather operational mode authorized under section 4(a). An exemption from diesel exhaust fluid system requirements under section 4(b) is also an exception.

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Cold Weather Diesel Reliability Act of 2025

Last updated: 3/11/2026 · Introduced: 11/6/2025

Author: Dan Sullivan (R-AK)

TL;DR (AI)

This bill directs the Environmental Protection Agency to allow manufacturers to temporarily suspend engine derate or shutdown functions in diesel vehicles during prolonged cold weather (at or below zero degrees Centigrade) when emissions control system faults occur.
The bill provides a year-round exemption from diesel exhaust fluid system requirements for diesel vehicles operating in extremely cold regions (north of 59 degrees north latitude) or where diesel exhaust fluid use is impractical.
This Act clarifies that it does not waive compliance with the Clean Air Act, except for the temporary cold-weather operational mode and diesel exhaust fluid exemption.

119th Congressin committeeHR. 6250(In Committee)Official page

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Includes provisions on preamble, short title., and 4 more.

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