{"data":{"id":"us/40-cfr-1065.303","jurisdiction":"us","citation":"40 CFR 1065.303","heading":"Summary of required calibration and verifications.","body":"The following table summarizes the required and recommended calibrations and verifications described in this subpart and indicates when these have to be performed:\nTable 1 of § 1065.303—Summary of Required Calibration and Verifications\nType of calibration or verification Minimum frequency a\n§ 1065.305: Accuracy, repeatability and noise Accuracy: Not required, but recommended for initial installation. Repeatability: Not required, but recommended for initial installation.\nNoise: Not required, but recommended for initial installation.\n§ 1065.307: Linearity verification\nSpeed: Upon initial installation, within 370 days before testing and after major maintenance.\nTorque: Upon initial installation, within 370 days before testing and after major maintenance.\nElectrical power, current, and voltage: Upon initial installation, within 370 days before testing and after major maintenance.b\nFuel mass flow rate: Upon initial installation, within 370 days before testing, and after major maintenance.\nFuel mass scale: Upon initial installation, within 370 days before testing, and after major maintenance.\nDEF mass flow rate: Upon initial installation, within 370 days before testing, and after major maintenance.c\nDEF mass scale: Upon initial installation, within 370 days before testing, and after major maintenance.\nIntake-air, dilution air, diluted exhaust, and batch sampler flow rates: Upon initial installation, within 370 days before testing and after major maintenance.d\nRaw exhaust flow rate: Upon initial installation, within 185 days before testing and after major maintenance.d\nGas dividers: Upon initial installation, within 370 days before testing, and after major maintenance.\nGas analyzers (unless otherwise noted): Upon initial installation, within 35 days before testing and after major maintenance.\nFTIR and photoacoustic analyzers: Upon initial installation, within 370 days before testing and after major maintenance.\nGC-ECD: Upon initial installation and after major maintenance.\nPM balance: Upon initial installation, within 370 days before testing and after major maintenance.\nPressure, temperature, and dewpoint: Upon initial installation, within 370 days before testing and after major maintenance.\n§ 1065.308: Continuous gas analyzer system response and updating-recording verification—for gas analyzers not continuously compensated for other gas species Upon initial installation or after system modification that would affect response.\n§ 1065.309: Continuous gas analyzer system-response and updating-recording verification—for gas analyzers continuously compensated for other gas species Upon initial installation or after system modification that would affect response.\n§ 1065.310: Torque Upon initial installation and after major maintenance.\n§ 1065.315: Pressure, temperature, dewpoint Upon initial installation and after major maintenance.\n§ 1065.320: Fuel flow Upon initial installation and after major maintenance.\n§ 1065.325: Intake flow Upon initial installation and after major maintenance.\n§ 1065.330: Exhaust flow Upon initial installation and after major maintenance.\n§ 1065.340: Diluted exhaust flow (CVS) Upon initial installation and after major maintenance.\n§ 1065.341: CVS and PFD flow verification (propane check) Upon initial installation, within 35 days before testing, and after major maintenance.e\n§ 1065.342 Sample dryer verification For thermal chillers: Upon installation and after major maintenance. For osmotic membranes; upon installation, within 35 days of testing, and after major maintenance.\n§ 1065.345: Vacuum leak For laboratory testing: Upon initial installation of the sampling system, within 8 hours before the start of the first test interval of each duty-cycle sequence, and after maintenance such as pre-filter changes.\nFor field testing: After each installation of the sampling system on the vehicle, prior to the start of the field test, and after maintenance such as pre-filter changes.\n§ 1065.350: CO2 NDIR H2 O interference Upon initial installation and after major maintenance.\n§ 1065.355: CO NDIR CO2 and H2 O interference Upon initial installation and after major maintenance.\n§ 1065.360: FID calibration THC FID optimization, and THC FID verification Calibrate all FID analyzers: upon initial installation and after major maintenance.\nOptimize and determine CH4 response for THC FID analyzers: upon initial installation and after major maintenance.\nVerify CH4 response for THC FID analyzers: upon initial installation, within 185 days before testing, and after major maintenance.\nVerify C2 H6 response for THC FID analyzers if used for NMNEHC determination: upon initial installation, within 185 days before testing, and after major maintenance.\n§ 1065.362: Raw exhaust FID O2 interference For all FID analyzers: upon initial installation, and after major maintenance.\nFor THC FID analyzers: upon initial installation, after major maintenance, and after FID optimization according to § 1065.360.\n§ 1065.365: Nonmethane cutter penetration Upon initial installation, within 185 days before testing, and after major maintenance.\n§ 1065.366: Interference verification for FTIR analyzers Upon initial installation and after major maintenance.\n§ 1065.369: H2 O, CO, and CO2 interference verification for ethanol photoacoustic analyzers Upon initial installation and after major maintenance.\n§ 1065.370: CLD CO2 and H2 O quench Upon initial installation and after major maintenance.\n§ 1065.372: NDUV HC and H2 O interference Upon initial installation and after major maintenance.\n§ 1065.375: N2 O analyzer interference Upon initial installation and after major maintenance.\n§ 1065.376: Chiller NO2 penetration Upon initial installation and after major maintenance.\n§ 1065.378: NO2-to-NO converter conversion Upon initial installation, within 35 days before testing, and after major maintenance.\n§ 1065.390: PM balance and weighing Independent verification: Upon initial installation, within 370 days before testing, and after major maintenance.\nZero, span, and reference sample verifications: Within 12 hours of weighing, and after major maintenance.\n§ 1065.395: Inertial PM balance and weighing Independent verification: Upon initial installation, within 370 days before testing, and after major maintenance.\nOther verifications: Upon initial installation and after major maintenance.\na Perform calibrations and verifications more frequently than we specify, according to measurement system manufacturer instructions and good engineering judgment.\nb Perform linearity verification either for electrical power or for current and voltage.\nc Linearity verification is not required if DEF flow rate comes directly from the ECM signal as described in § 1065.247(b).\nd Linearity verification is not required if the flow signal's accuracy is verified by carbon balance error verification as described in § 1065.307(e)(5) or a propane check as described in § 1065.341.\ne CVS and PFD flow verification (propane check) is not required for measurement systems verified by linearity verification as described in § 1065.307 or carbon balance error verification as described in § 1065.341(h).","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER U—AIR POLLUTION CONTROLS","PART 1065—ENGINE-TESTING PROCEDURES","Subpart D—Calibrations and Verifications"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"c32b03d8f67c846a7fc795904daf1c89bb4744ef2b3c8d06260f61c2fba95fcf","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-1065.301","next":"us/40-cfr-1065.305"},"notice":"GroundRules: Original legal text. Not legal advice."}