40 CFR § 86.1917 - How does in-use testing under this subpart relate to the emission-related warranty in Section 207(a)(1) of the Clean Air Act?

---
identifier: "/us/cfr/t40/s86.1917"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 86.1917 - How does in-use testing under this subpart relate to the emission-related warranty in Section 207(a)(1) of the Clean Air Act?"
title_number: 40
title_name: "Protection of Environment"
section_number: "86.1917"
section_name: "How does in-use testing under this subpart relate to the emission-related warranty in Section 207(a)(1) of the Clean Air Act?"
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "86"
part_name: "CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401-7671q."
cfr_part: "86"
---


# 86.1917 How does in-use testing under this subpart relate to the emission-related warranty in Section 207(a)(1) of the Clean Air Act?

(a) An exceedance of the NTE found through the in-use testing program under this subpart is not by itself sufficient to show a breach of warranty under Clean Air Act section 207(a)(1) (42 U.S.C. 7541(a)(1)). A breach of warranty would also require one of the following things:

(1) That, at the time of sale, the engine or vehicle was designed, built, and equipped in a manner that does not conform in all material respects reasonably related to emission controls to the engine as described in the application for certification and covered by the certificate; or

(2) A defect in materials or workmanship of a component causes the vehicle or engine to fail to conform to the applicable regulations for its useful life.

(b) To the extent that in-use NTE testing does not reveal such a material deficiency at the time of sale in the design or manufacture of an engine compared with the certified engine, or a defect in the materials and workmanship of a component or part, test results showing an exceedance of the NTE by itself would not show a breach of the warranty under 42 U.S.C. 7541(a)(1).