From the EPA site:
https://www.epa.gov/transportation-...frequent-questions-related-transportation-air
"The
Clean Air Act requires manufacturers of light-duty vehicles to provide two federal emission control warranties: (A) "Performance Warranty" and (B) "Design and Defect Warranty." These warranties are provided by the vehicle manufacturer and apply to used vehicles as well. The warranty period begins from the date of sale to the original owner.
The Performance Warranty covers repairs which are required during the first 2 years or 24,000 miles of vehicle use (whichever first occurs) because the vehicle failed an emission test. Specified major emission control components are covered for the first 8 years or 80,000 miles (whichever first occurs). The specified major emission control components
only include the catalytic converters, the electronic emissions control unit or computer (ECU), and the onboard emissions diagnostic (OBD) device or computer. If you are a resident of an area with an Inspection and Maintenance (I/M) program that meets federal guidelines, you are eligible for this warranty protection provided that:
- Your car or light-duty truck fails an approved emissions test; and
- Your vehicle is less than 2 years old and has less than 24,000 miles (up to 8 years/80,000 miles for certain components); and
- Your state or local government requires that you repair the vehicle; and
- The test failure does not result from misuse of the vehicle or a failure to follow the manufacturers’ written maintenance instructions; and
- You present the vehicle to a warranty-authorized manufacturer representative, along with evidence of the emission test failure, during the warranty period.
The Design and Defect warranty covers repair of emission control or emission related parts which fail to function or function improperly because of a defect in materials or workmanship for 2 years or 24,000 miles (whichever first occurs), and the specified major emissions control components mentioned above for 8 years or 80,000 miles (whichever first occurs). The manufacturer can deny this warranty coverage if evidence shows that the emission component failure was caused by improper use or maintenance and not caused by a defect."
Your owners manual should lay out what those special major emissions controls are and the coverage