(a) This subpart specifies the equipment and procedures for performing exhaust-emission tests on Otto-cycle and diesel-cycle heavy-duty engines. Subpart A of this part sets forth the emission standards and general testing requirements to comply with EPA certification procedures.

(b) Use the applicable equipment and procedures for spark-ignition or compression-ignition engines in 40 CFR part 1065 to determine whether engines meet the duty-cycle emission standards in subpart A of this part. Measure the emissions of all regulated pollutants as specified in 40 CFR part 1065. Use the duty cycles and procedures specified in §§ 86.1333, 86.1360, and 86.1362. Adjust emission results from engines using aftertreatment technology with infrequent regeneration events as described in § 86.004-28.

(c) The provisions in §§ 86.1370 and 86.1372 apply for determining whether an engine meets the applicable not-to-exceed emission standards.

(d) Measure smoke using the procedures in subpart I of this part for evaluating whether engines meet the smoke standards in subpart A of this part.

(e) Use the fuels specified in 40 CFR part 1065 to perform valid tests, as follows:

(1) For service accumulation, use the test fuel or any commercially available fuel that is representative of the fuel that in-use engines will use.

(2) For diesel-fueled engines, use the ultra low-sulfur diesel fuel specified in 40 CFR part 1065 for emission testing.

(3) For gasoline-fueled engines, use the appropriate E10 fuel specified in 40 CFR part 1065; however, through model year 2021 you may instead use the appropriate E0 fuel specified in 40 CFR part 1065, with the exception that the E0 fuel must have sulfur concentration between 0.0015 and 0.008 weight percent and research octane of at least 93. Starting in model year 2022, you may certify up to 5 percent of your nationwide sales volume of engines certified under subpart A of this part in a given model year based on this E0 test fuel if those engines are certified with carryover data.

(f) You may use special or alternate procedures to the extent we allow them under 40 CFR 1065.10. In addition, for 2010 and earlier model year engines, you may use modified test procedures as needed to conform to the procedures that were specified at the time of emission testing for the model year in question.

(g) This subpart applies to you as a manufacturer, and to anyone who does testing for you.

(h) For testing conducted with engines installed in vehicles, including field testing conducted to measure emissions under Not-To-Exceed test procedures, use the test procedures and equipment specified in 40 CFR part 1065, subpart J.

(i) You may disable any AECDs that have been approved solely for emergency vehicle applications under paragraph (4) of the definition of “Defeat device” in § 86.004-2. The emission standards do not apply when any of these AECDs are active.