The U.S. Environmental Protection Agency has issued new guidance confirming that federal emissions law supports farmers’ and equipment owners’ right to repair their own nonroad diesel equipment.
Specifically, the guidance explains that the Clean Air Act (CAA) does not block access to diagnostic tools, software or repair information. Instead, it allows farmers and independent repair shops to temporarily disable certain emissions control systems when necessary to complete repairs. Afterward, equipment must return to proper, compliant operation.
According to EPA officials, confusion around emissions rules has persisted for years. As a result, many farmers relied on authorized dealers for repairs that could have been completed in the field or at nearby repair shops. For farmers, timely and affordable repairs remain essential to planting, harvesting and keeping operations running.
What the Guidance Clarifies
For years, some equipment manufacturers interpreted the Clean Air Act’s anti-tampering provisions as limiting access to emissions-related repair tools and software. However, EPA says those interpretations went beyond what the law requires.
Under the updated guidance, EPA makes clear that:
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Temporary overrides of emissions control systems are allowed for repair or maintenance
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Equipment must return to its certified, compliant configuration once repairs are complete
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The Clean Air Act does not require repairs to be performed by authorized dealers only
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The law places no limits on the type of tools used for legitimate repairs
Notably, the clarification applies to nonroad diesel engines equipped with modern emissions technologies. These include selective catalytic reduction (SCR) systems, inducement systems and Diesel Exhaust Fluid (DEF) components.
At the same time, EPA emphasized that the guidance does not change emissions standards or weaken environmental protections.
What This Means for Farmers and Equipment Owners
In practical terms, EPA and agriculture officials expect the guidance to reduce repair delays and costs, especially during critical fieldwork periods.
For years, farmers have raised concerns about limited repair access. In many cases, those limits increased downtime and raised repair bills. In some situations, producers kept older equipment in service simply because it was easier to fix.
EPA stressed that the law should not act as a barrier to timely and affordable maintenance. At the same time, the agency noted that improved repair access could encourage greater use of newer equipment with advanced emissions controls, supporting both productivity and environmental goals.
Background on the EPA Action
The guidance follows a June 2025 request from John Deere, which asked EPA to confirm that temporary emissions system overrides are allowed for repair purposes. In response, EPA reaffirmed existing policy under the Clean Air Act and related federal regulations.
Earlier, in August 2025, EPA issued additional guidance urging manufacturers to revise DEF system software. That guidance aimed to prevent sudden engine shutdowns during faults. As a result, operators gained more time to complete repairs without compromising safety or productivity.
Although the guidance does not carry the force of law, EPA says it provides clear direction. Specifically, it explains how existing regulations apply to manufacturers, equipment owners and repair providers.
Where to Find the Guidance
EPA’s full guidance document outlines when and how temporary emissions system overrides may be used during repairs. It also explains the steps required to restore equipment to compliant operation.
Producers and equipment owners can review the guidance directly through EPA’s website.
