40 CFR § 86.150-98 - Refueling test procedure; overview.
(a) The refueling emissions test procedure described in this and subsequent sections is used to determine the conformity of vehicles with the refueling emissions standards set forth in subpart A of this part for light-duty vehicles and light-duty trucks. The refueling emissions test procedure may be performed as an individual test or in combination with the evaporative and exhaust emissions test sequences of § 86.130-96.
(b) The refueling emissions test is designed to measure hydrocarbon emissions resulting from the generation or displacement of fuel tank vapor during vehicle refueling. The refueling emissions shall be measured by the enclosure technique.
(c) All emission control systems installed on or incorporated in a new motor vehicle shall be functioning during all procedures in this subpart except:
(2) during certain specified fuel drain and fill operations, at which times the refueling emission control canister is disconnected. Maintenance to correct component malfunction or failure shall be authorized in accordance with § 86.098-25.