The U.S. Environmental Protection Agency on Wednesday issued new guidance requiring vehicle and equipment manufacturers to provide independent repair shops and consumers with the same diagnostic and repair information available to branded service centers.
The move, which covers light-, medium-, and heavy-duty vehicles, specifically addresses access to tools and data needed to fix Diesel Exhaust Fluid (DEF) and other emissions control systems.
Under EPA’s regulations, manufacturers must provide:
- Full emissions-related service information
- Training materials
- OBD data and enhanced diagnostics
- Passthrough reprogramming information
- Manufacturer-specific tools for purchase
Manufacturers have an obligation to release necessary service data, training materials, and tools on reasonable terms, the agency said.
The action follows a presidential memorandum issued two days ago by President Donald Trump titled “Lowering the Cost of Living by Promoting the Freedom to Fix.” It builds on a February 2026 EPA measure that extended similar right-to-repair provisions granted to farmers and other users of off-road diesel equipment.
Independent mechanics and vehicle owners have long faced hurdles repairing complex emissions systems. Manufacturers have often cited the Clean Air Act’s (CAA) anti-tampering laws as a reason to withhold certain digital tools and software, arguing that sharing them could facilitate the illegal bypassing of emissions controls leaving—operators no choice but to tow or limp vehicles to OEM-branded dealerships.
The EPA's new guidance clarifies that the CAA allows temporary overrides of emissions systems if done strictly for the "purpose of repair."
"EPA's implementing regulations state that individuals may repair the engine or equipment if it is restored to proper functioning when the repair is complete or may modify an engine or equipment to respond to a temporary emergency and as long as it is restored to proper functioning as soon as possible," the agency noted in its guidance Wednesday. "This means that the use of one or more procedures and/or tools that temporarily take a product out of its certified configuration as necessary to perform maintenance and/or repair are not prohibited acts provided the vehicle or engine is returned to its certified configuration before being returned to service.
Additionally, the EPA reinforced consumer protection rules under the CAA, writing that manufacturers cannot mandate the use of OEM-branded parts and must allow for the use of equivalent generic parts for emissions repairs.
EPA formally recognized the Specialty Equipment Market Association (SEMA) as an alternative certification authority for aftermarket vehicle parts. Moving forward, SEMA Certified Emissions (SC-E) Program will indicate compliance with the Clean Air Act (CAA) and verify that approved aftermarket parts do not negatively impact vehicle emissions.
The EPA emphasized that the guidance does not alter existing laws, weaken federal emissions standards, or require manufacturers to disclose proprietary software codes, trade secrets, or intellectual property.
Trump's memo and EPA's directive are different than the Right to Equitable and Professional Auto Industry Repair Act (REPAIR ACT, H.R. 1566), introduced by Representative Neal Dunn (FL-02). That is a federal bill that guarantees vehicle owners and independent repair shops access to the diagnostic data, tools, and repair information necessary to fix modern connected vehicles. That bill has advanced through committee markups, but has seen no action since February.
