§ 85.505 Overview.
(a) You are exempted from the tampering prohibition in Clean Air Act section 203(a)(3) (42 U.S.C. 7522)(a)(3) (“tampering”) if you satisfy all the provisions of this subpart.
(b) The tampering exemption provisions described in this subpart are differentiated based on the age of the vehicle/engine at the point of conversion as follows:
(1) “New and relatively new” refers to a vehicle/engine where the date of conversion is in a calendar year that is not more than one year after the original model year. See § 85.510 for provisions that apply specifically to new and relatively new vehicles/engines.
(2) “Intermediate age” refers to a vehicle/engine that has not exceeded the useful life (in years, miles, or hours of operation) applicable to the vehicle/engine as originally certified, excluding new and relatively new vehicles/engines. See § 85.515 for provisions that apply specifically to intermediate-age vehicles/engines.