H.R. 6250: Cold Weather Diesel Reliability Act of 2025

This bill, known as the Cold Weather Diesel Reliability Act of 2025, aims to address specific issues related to diesel vehicles in cold weather conditions. It is designed to help prevent engine shutdowns and performance reductions due to emissions control failures when temperatures drop significantly. Below are the main provisions and objectives of the bill:

Purpose of the Bill

The bill is intended to allow manufacturers of certain diesel vehicles to maintain engine performance during cold weather, particularly when temperatures are at or below zero degrees Celsius (32 degrees Fahrenheit). The aim is to ensure that critical transportation and emergency services can operate safely and effectively in rural and cold regions.

Key Findings

The legislation acknowledges the following:

• Diesel vehicles play a crucial role in providing transportation and emergency services in cold climates.
• In rural areas experiencing prolonged freezing conditions, the use of diesel exhaust fluid can be unreliable, leading to operational challenges.
• Automatic engine shutdowns or power reductions caused by emissions control malfunctions can pose serious risks to safety and mobility.
• Emissions control regulations should not compromise human safety or disrupt essential transportation functions.

Regulatory Changes

The bill directs the Administrator of the Environmental Protection Agency (EPA) to implement specific regulatory changes within 180 days of the bill's enactment:

Engine Operational Flexibility

The EPA must revise existing regulations to permit covered manufacturers to suspend engine derate (performance reduction) or shutdown functions related to emissions control system faults under the following conditions:

• This suspension can occur only when external temperatures are at or below zero degrees Celsius.
• The engine must return to standard emissions control operations once temperatures rise above zero degrees Celsius.
• This exemption is necessary to avoid risks to safety, equipment failures, or loss of transportation function in remote areas.

Exemption from Diesel Exhaust Fluid Requirements

The bill mandates the EPA to grant a year-round exemption from diesel exhaust fluid requirements for specific covered vehicles, including:

• Vehicles predominantly operated north of 59 degrees north latitude.
• Vehicles encountering prolonged low temperatures or operational challenges that make the use of diesel exhaust fluid impractical.

Compliance with Emissions Standards

The bill clarifies that compliance with emissions standards under the Clean Air Act remains in effect, with exceptions only for the cold-weather operational provisions and the exemptions for diesel exhaust fluid systems as outlined.

Impact on Manufacturers

This legislation specifically targets diesel vehicle manufacturers, allowing them to make critical adjustments to engine management systems to serve better in cold weather conditions. The underlying motivation is to balance regulatory compliance with safety and operational efficiency in harsh climates.

Relevant Companies

• GM (General Motors): As a manufacturer of diesel vehicles, changes to how they manage engine performance in cold weather could affect their operational protocols and product offerings.
• F (Ford Motor Company): Similar to GM, Ford could be impacted by the need to adjust performance controls related to emissions in colder regions, potentially influencing their designs and regulatory submissions.
• DHIL (Diesel Holdings): Being involved in diesel engine manufacturing, this company could see changes in engine specifications due to the adjustments permitted by this legislation.