Cold Weather Diesel Reliability Act of 2025 | ChamberLight
Bills · HR 6250
IN COMMITTEE· 119TH CONGRESS
House BillHR 6250Environmental Protection
Cold Weather Diesel Reliability Act of 2025
INTRO NOV 21· LAST ACTION NOV 21
READING
4MIN
COSPONSORS
1
READER REACTIONS0 TOTAL
NO VOTES YET · BE THE FIRST
Introduced only
LEGISLATIVE PROGRESS
STEP 2 / 8
Introduced
In Committee
Reported
Passed House
Passed Senate
Conference
To President
Became Law
WHAT THE BILL DOES
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This bill matters to voters because it addresses a critical safety and logistical challenge in cold weather regions. Modern diesel vehicles, while cleaner, can experience automatic engine shutdowns or power reductions if their emissions control systems, like those using Diesel Exhaust Fluid (DEF), malfunction or freeze in extreme cold. In remote or rural areas, such failures can leave people stranded, disrupt emergency services, or halt vital transportation of goods and fuel, potentially creating life-threatening situations.
If this bill becomes law, it would prioritize the reliable operation of essential diesel vehicles in dangerous cold, mitigating risks to public safety and ensuring critical services can continue. For example, a snowplow, ambulance, or delivery truck operating in sub-zero temperatures would be less likely to become inoperable due to an emissions system fault. If it doesn't pass, the current regulations would continue to pose these challenges, potentially leading to ongoing safety concerns and logistical difficulties for those living and working in harsh winter environments.
KEY PROVISIONS
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PROVISION 01
Requires the EPA to allow manufacturers to temporarily suspend engine derate or shutdown functions triggered by emissions control system faults when ambient temperatures are at or below 0 degrees Celsius.
This allows critical diesel vehicles to maintain full power and functionality in dangerous cold conditions, preventing breakdowns.
PROVISION 02
The temporary suspension is subject to conditions: it must be necessary to prevent occupational danger or loss of essential transportation in remote areas, and the engine must return to normal emissions control operation when temperatures rise above 0 degrees Celsius.
This ensures the flexibility is used only when truly critical for safety and operational necessity, and that emissions controls are re-engaged when conditions allow.
PROVISION 03
Requires the EPA to grant a year-round exemption from Diesel Exhaust Fluid (DEF) system requirements for covered vehicles primarily operated north of 59 degrees north latitude or in conditions where DEF use is consistently impractical due to prolonged cold.
This provides a long-term solution for specific regions where DEF systems are consistently unreliable due to extreme cold, addressing a major cause of operational issues.
PROVISION 04
The year-round exemption includes relief from engine derate or shutdown functions triggered by any issues with the DEF system.
It ensures comprehensive protection against DEF-related operational failures for vehicles in the most challenging cold environments.
This bill matters to voters because it addresses a critical safety and logistical challenge in cold weather regions. Modern diesel vehicles, while cleaner, can experience automatic engine shutdowns or power reductions if their emissions control systems, like those using Diesel Exhaust Fluid (DEF), malfunction or freeze in extreme cold. In remote or rural areas, such failures can leave people stranded, disrupt emergency services, or halt vital transportation of goods and fuel, potentially creating life-threatening situations.
If this bill becomes law, it would prioritize the reliable operation of essential diesel vehicles in dangerous cold, mitigating risks to public safety and ensuring critical services can continue. For example, a snowplow, ambulance, or delivery truck operating in sub-zero temperatures would be less likely to become inoperable due to an emissions system fault. If it doesn't pass, the current regulations would continue to pose these challenges, potentially leading to ongoing safety concerns and logistical difficulties for those living and working in harsh winter environments.
KEY PROVISIONS
AI-extracted
high
Requires the EPA to allow manufacturers to temporarily suspend engine derate or shutdown functions triggered by emissions control system faults when ambient temperatures are at or below 0 degrees Celsius.
This allows critical diesel vehicles to maintain full power and functionality in dangerous cold conditions, preventing breakdowns.
med
The temporary suspension is subject to conditions: it must be necessary to prevent occupational danger or loss of essential transportation in remote areas, and the engine must return to normal emissions control operation when temperatures rise above 0 degrees Celsius.
This ensures the flexibility is used only when truly critical for safety and operational necessity, and that emissions controls are re-engaged when conditions allow.
high
Requires the EPA to grant a year-round exemption from Diesel Exhaust Fluid (DEF) system requirements for covered vehicles primarily operated north of 59 degrees north latitude or in conditions where DEF use is consistently impractical due to prolonged cold.
This provides a long-term solution for specific regions where DEF systems are consistently unreliable due to extreme cold, addressing a major cause of operational issues.
high
The year-round exemption includes relief from engine derate or shutdown functions triggered by any issues with the DEF system.
It ensures comprehensive protection against DEF-related operational failures for vehicles in the most challenging cold environments.
Not later than 180 days after the date of enactment.
EPA Administrator required to revise applicable Clean Air Act regulations.
GLOSSARY
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Administrator (of the EPA)
The head of the Environmental Protection Agency, the government body responsible for protecting human health and the environment.
Covered Manufacturer
A company that makes the specific types of diesel vehicles or engines that this bill applies to.
Covered Vehicle
An on-road diesel truck or a piece of off-road diesel equipment (like construction machinery) that is subject to the provisions of this bill.
Engine Derate
A feature where a vehicle's engine automatically reduces its power output, often triggered by a problem in the emissions control system to ensure compliance with environmental standards.
Engine Shutdown Function
A safety or compliance feature that automatically turns off a vehicle's engine, typically in response to a serious issue with the emissions control system.
Diesel Exhaust Fluid (DEF) System
A system in modern diesel vehicles that injects a liquid chemical into the exhaust stream to reduce harmful nitrogen oxide emissions. Problems with this system can lead to engine derate or shutdown.
Clean Air Act
ACTION TIMELINE
2 EVENTS
NOV 21, 25
Introduced in House
INTROREFERRAL
NOV 21, 25
Referred to the House Committee on Energy and Commerce.
A federal law that governs air pollution from stationary and mobile sources, establishing national air quality standards and regulating emissions.
59 Degrees North Latitude
An imaginary line circling the Earth at a specific distance from the equator, often used to define very northern regions, such as parts of Alaska and Canada, that experience extreme cold.
