85.2222—On-board diagnostic test procedures.
(a) General requirements—
(1) Exhaust gas sampling algorithm.
The analysis of exhaust gas concentrations begins ten seconds after the applicable test mode begins. Exhaust gas concentrations must be analyzed at a minimum rate of once every 0.75 second. The measured value for pass/fail determinations is a simple running average of the measurements taken over five seconds.
(2) Pass/fail determination.
A pass or fail determination is made for each applicable test mode based on a comparison of the short test standards contained in §§ 85.2203 and 85.2204, and the measured value for HC and CO as described in paragraph (a)(1) of this section. A vehicle passes the test mode if any pair of simultaneous values for HC and CO are below or equal to the applicable short test standards. A vehicle fails the test mode if the values for either HC or CO, or both, in all simultaneous pairs of values are above the applicable standards.
(3) Void test conditions.
The test immediately terminates and any exhaust gas measurements are voided if the measured concentration of CO plus CO2 falls below six percent or the vehicle's engine stalls at any time during the test sequence.
(4) Multiple exhaust pipes.
Exhaust gas concentrations from vehicle engines equipped with multiple exhaust pipes must be sampled simultaneously.
(b) Test sequence.
(1)
The test sequence consists of a first-chance test and a second-chance test as described in paragraphs (b)(1) (i) and (ii) of this section.
(i)
The first-chance test, as described under paragraph (c) of this section, consists of a first-chance high-speed mode followed immediately by a first-chance idle mode.
(ii)
The second-chance test as described under paragraph (d) of this section is performed only if the vehicle fails the first-chance test.
(2)
The test sequence begins only after the requirements described in paragraphs (b)(2) (i) through (iv) of this section are met.
(i)
The vehicle is tested in as-received condition with the transmission in neutral or park and all accessories turned off. The engine must be at normal operating temperature (as indicated by a temperature gauge, temperature lamp, touch test on the radiator hose, or other visual observation indicating that overheating has not occurred).
(ii)
For all pre-1996 model year vehicles, a tachometer shall be attached to the vehicle in accordance with the analyzer manufacturer's instructions. For 1996 and newer model year vehicles the OBD data link connector will be used to monitor RPM. In the event that an OBD data link connector is not available or that an RPM signal is not available over the data link connector, a tachometer shall be used instead.
(iii)
The sample probe is inserted into the vehicle's tailpipe to a minimum depth of 10 inches. If the vehicle's exhaust system prevents insertion to this depth, a tailpipe extension must be used.
(c) First-chance test.
The test timer starts (tt=0) when the conditions specified in paragraph (b)(2) of this section are met. The overall maximum test time is 290 seconds (tt=290). The first-chance test consists of a high-speed mode followed immediately by an idle mode.
(1) First-chance high-speed mode.
(i)
The mode timer starts (mt=0) when the vehicle engine speed is between 2200 and 2800 rpm. If the engine speed falls below 2200 rpm or exceeds 2800 rpm for more than two seconds in one excursion, or more than six seconds over all excursions within 30 seconds of the final measured value used in the pass/fail determination, the measured value is invalidated and the mode continued. If any excursion lasts for more than ten seconds, the mode timer resets to zero (mt=0) and timing resumes. The high-speed mode length is 90 seconds elapsed time (mt=90).
(ii)
The pass/fail analysis begins after an elapsed time of ten seconds (mt=10). A pass or fail determination is made for the vehicle and the mode is terminated in accordance with paragraphs (c)(1)(ii)(A) through (C) of this section.
(A)
The vehicle passes the high-speed mode and the mode is terminated at an elapsed time of 90 seconds (mt=90) if any measured values are less than or equal to the applicable short test standards as determined by the procedure described in paragraph (a)(2) of this section.
(B)
The vehicle fails the high-speed mode and the mode is terminated if the requirements of paragraph (c)(1)(ii)(A) of this section are not satisfied by an elapsed time of 90 seconds (mt=90).
(C) Optional.
The vehicle may fail the first-chance test and any subsequent test may be omitted if no exhaust gas concentration lower than 1800 ppm HC is found at an elapsed time of 30 seconds (mt=30).
(2) First-chance idle mode.
(i)
The mode timer starts (mt=0) when the vehicle engine speed is between 350 and 1100 rpm. If the engine speed exceeds 1100 rpm or falls below 350 rpm, the mode timer resets to zero and resumes timing. The minimum first-chance idle mode length is determined as described in paragraph (c)(2)(ii) of this section. The maximum first-chance idle mode length is 90 seconds elapsed time (mt=90).
(ii)
The pass/fail analysis begins after an elapsed time of ten seconds (mt=10). A pass or fail determination is made for the vehicle and the mode is terminated in accordance with paragraphs (c)(2)(ii) (A) through (D) of this section.
(A)
The vehicle passes the idle mode and the test is immediately terminated if, prior to an elapsed time of 30 seconds (mt=30), measured values are less than or equal to 100 ppm HC and 0.5 percent CO.
(B)
The vehicle passes the idle mode and the test is terminated at the end of an elapsed time of 30 seconds (mt=30) if, prior to that time, the criteria of paragraph (c)(2)(ii)(A) of this section are not satisfied, and the measured values are less than or equal to the applicable short test standards as determined by the procedure described in paragraph (a)(2) of this section.
(C)
The vehicle passes the idle mode and the test is immediately terminated if, at any point between an elapsed time of 30 seconds (mt=30) and 90 seconds (mt=90), the measured values are less than or equal to the applicable short test standards as determined by the procedure described in paragraph (a)(2) of this section.
(D)
The vehicle fails the idle mode and the test is terminated if none of the provisions of paragraphs (c)(2)(ii) (A), (B), and (C) of this section is satisfied by an elapsed time of 90 seconds (mt=90). Alternatively, the vehicle may be failed if the provisions of paragraphs (c)(2) (i) and (ii) of this section are not met within the elapsed time of 30 seconds.
(d) Second-chance test.
(1)
If the vehicle fails either mode of the first-chance test, the test timer resets to zero (tt=0) and a second-chance test begins. The second-chance test is performed based on the first-chance test failure mode or modes as described in paragraphs (d)(1) (i) through (iii) of this section.
(i)
If the vehicle failed only the first-chance high-speed mode, the second-chance test consists of a second-chance high-speed mode as described in paragraph (d)(2) of this section. The overall maximum test time is 280 seconds (tt=280).
(ii)
If the vehicle failed only the first-chance idle mode, the second-chance test consists of a second-chance pre-conditioning mode followed immediately by a second-chance idle mode as described in paragraphs (d) (3) and (4) of this section. The overall maximum test time is 425 seconds (tt=425).
(iii)
If both the first-chance high-speed mode and first-chance idle mode were failed, the second-chance test consists of the second-chance high-speed mode followed immediately by the second-chance idle mode as described in paragraphs (d) (2) and (4) of this section. However, if during this second-chance procedure, the vehicle fails the second-chance high-speed mode, then the second-chance idle mode may be eliminated. The overall maximum test time is 425 seconds (tt=425).
(2) Second-chance high-speed mode—
(i) Ford Motor Company and Honda vehicles.
The engines of 1981-1987 model year Ford Motor Company vehicles and 1984-1985 model year Honda Preludes must be shut off for not more than ten seconds and then restarted. The probe may be removed from the tailpipe or the sample pump turned off if necessary to reduce analyzer fouling during the restart procedure. This procedure may also be used for 1988-1989 model year Ford Motor Company vehicles but may not be used for other vehicles.
(ii)
The mode timer resets (mt=0) when the vehicle engine speed is between 2200 and 2800 rpm. If the engine speed falls below 2200 rpm or exceeds 2800 rpm for more than two seconds in one excursion, or more than six seconds over all excursions within 30 seconds of the final measured value used in the pass/fail determination, the measured value is invalidated and the mode continued. The minimum second-chance high-speed mode length is determined as described in paragraphs (d)(2) (iii) and (iv) of this section. If any excursion lasts for more than ten seconds, the mode timer resets to zero (mt=0) and timing resumes. The maximum second-chance high-speed mode length is 180 seconds elapsed time (mt=180).
(iii)
In the case where the second-chance high-speed mode is not followed by the second-chance idle mode, the pass/fail analysis begins after an elapsed time of ten seconds (mt=10). A pass or fail determination is made for the vehicle and the mode is terminated in accordance with paragraphs (d)(2)(iii) (A) through (D) of this section.
(A)
The vehicle passes the high-speed mode and the test is immediately terminated if, prior to an elapsed time of 30 seconds (mt=30), measured values are less than or equal to 100 ppm HC and 0.5 percent CO.
(B)
The vehicle passes the high-speed mode and the test is terminated if at the end of an elapsed time of 30 seconds (mt=30) if, prior to that time, the criteria of paragraph (d)(2)(iii)(A) of this section are not satisfied, and the measured values are less than or equal to the applicable short test standards as determined by the procedure described in paragraph (a)(2) of this section.
(C)
The vehicle passes the high-speed mode and the test is immediately terminated if, at any point between an elapsed time of 30 seconds (mt=30) and 180 seconds (mt=180), the measured values are less than or equal to the applicable short test standards as determined by the procedure described in paragraph (a)(2) of this section.
(D)
The vehicle fails the high-speed mode and the test is terminated if none of the provisions of paragraphs (d)(2)(iii) (A), (B), and (C) of this section is satisfied by an elapsed time of 180 seconds (mt=180).
(iv)
In the case where the second-chance high-speed mode is followed by the second-chance idle mode, the pass/fail analysis begins after an elapsed time of ten seconds (mt=10). A pass or fail determination is made for the vehicle and the mode is terminated in accordance with paragraphs (d)(2)(iv)(A) and (B) of this section.
(A)
The vehicle passes the high-speed mode and the mode is terminated at the end of an elapsed time of 180 seconds (mt=180) if any measured values are less than or equal to the applicable short test standards as determined by the procedure described in paragraph (a)(2) of this section.
(B)
The vehicle fails the high-speed mode and the mode is terminated if paragraph (d)(2)(iv)(A) of this section is not satisfied by an elapsed time of 180 seconds (mt=180).
(3) Second-chance preconditioning mode.
The mode timer starts (mt=0) when engine speed is between 2200 and 2800 rpm. The mode continues for an elapsed time of 180 seconds (mt=180). If the engine speed falls below 2200 rpm or exceeds 2800 rpm for more than five seconds in any one excursion, or 15 seconds over all excursions, the mode timer resets to zero and resumes timing.
(4) Second-chance idle mode—
(i) Ford Motor Company and Honda vehicles.
The engines of 1981-1987 model year Ford Motor Company vehicles and 1984-1985 model year Honda Preludes must be shut off for not more than ten seconds and then restarted. The probe may be removed from the tailpipe or the sample pump turned off if necessary to reduce analyzer fouling during the restart procedure. This procedure may also be used for 1988-1989 model year Ford Motor Company vehicles but may not be used for other vehicles.
(ii)
The mode timer starts (mt=0) when the vehicle engine speed is between 350 and 1100 rpm. If the engine speed exceeds 1100 rpm or falls below 350 rpm the mode timer resets to zero and resumes timing. The minimum second-chance idle mode length is determined as described in paragraph (d)(4)(iii) of this section. The maximum second-chance idle mode length is 90 seconds elapsed time (mt=90).
(iii)
The pass/fail analysis begins after an elapsed time of ten seconds (mt=10). A pass or fail determination is made for the vehicle and the mode is terminated in accordance with paragraphs (d)(4)(iii) (A) through (D) of this section.
(A)
The vehicle passes the second-chance idle mode and the test is immediately terminated if, prior to an elapsed time of 30 seconds (mt=30), measured values are less than or equal to 100 ppm HC and 0.5 percent CO.
(B)
The vehicle passes the second-chance idle mode and the test is terminated at the end of an elapsed time of 30 seconds (mt=30) if, prior to that time, the criteria of paragraph (d)(4)(iii)(A) of this section are not satisfied, and the measured values are less than or equal to the applicable short test standards as determined by the procedure described in paragraph (a)(2) of this section.
(C)
The vehicle passes the second-chance idle mode and the test is immediately terminated if, at any point between an elapsed time of 30 seconds (mt=30) and 90 seconds (mt=90), measured values are less than or equal to the applicable short test standards described in paragraph (a)(2) of this section.
(D)
The vehicle fails the second-chance idle mode and the test is terminated if none of the provisions of paragraphs (d)(4)(iii) (A), (B), and (C) of this section is satisfied by an elapsed time of 90 seconds (mt=90).
Code of Federal Regulations
The test sequence for the inspection of on-board diagnostic systems on 1996 and newer light-duty vehicles and light-duty trucks shall consist of the following steps:
(a)
The on-board diagnostic inspection shall be conducted with the key-on/engine running (KOER), with the exception of inspecting for MIL illumination as required in paragraph (d)(4) of this section, during which the inspection shall be conducted with the key-on/engine off (KOEO).
(c)
The test system shall send a Mode $01, PID $01 request in accordance with SAE J1979 to determine the evaluation status of the vehicle's on-board diagnostic system. The test system shall determine what monitors are supported by the on-board diagnostic system, and the readiness evaluation for applicable monitors in accordance with SAE J1979. The procedure shall be done in accordance with SAE J1979 “E/E Diagnostic Test Modes,” (DEC91). This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of SAE J1979 may be obtained from the Society of Automotive Engineers, Inc., 400 Commonwealth Drive, Warrendale, PA 15096-0001. Copies may be inspected at the EPA Docket No. A-94-21 at EPA's Air Docket (LE-131), Room 1500 M, 1st Floor, Waterside Mall, 401 M Street SW., Washington, DC, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
(1)
Coincident with the beginning of mandatory testing, repair, and retesting based upon the OBD-I/M check, if the readiness evaluation indicates that any on-board tests are not complete the customer shall be instructed to return after the vehicle has been run under conditions that allow completion of all applicable on-board tests. If the readiness evaluation again indicates that any on-board test is not complete the vehicle shall be failed.
(2)
An exception to paragraph (c)(1) of this section is allowed for MY 1996 to MY 2000 vehicles, inclusive, with two or fewer unset readiness monitors, and for MY 2001 and newer vehicles with no more than one unset readiness monitor. Vehicles from those model years which would otherwise pass the OBD inspection, but for the unset readiness code(s) in question may be issued a passing certificate without being required to operate the vehicle in such a way as to activate those particular monitors. Vehicles from those model years with unset readiness codes which also have diagnostic trouble codes (DTCs) stored resulting in a lit malfunction indicator light (MIL) must be failed, though setting the unset readiness flags in question shall not be a prerequisite for passing the retest.
(d)
The test system shall evaluate the malfunction indicator light status bit and record status information in the vehicle test record.
(1)
If the malfunction indicator status bit indicates that the malfunction indicator light (MIL) has been commanded to be illuminated the test system shall send a Mode $03 request to determine the stored diagnostic trouble codes (DTCs). The system shall repeat this cycle until the number of codes reported equals the number expected based on the Mode 1 response. All DTCs resulting in MIL illumination shall be recorded in the vehicle test record and the vehicle shall fail the on-board diagnostic inspection.
(2)
If the malfunction indicator light bit is not commanded to be illuminated the vehicle shall pass the on-board diagnostic inspection, even if DTCs are present.
(3)
If the malfunction indicator light bit is commanded to be illuminated, the inspector shall visually inspect the malfunction indicator light to determine if it is illuminated. If the malfunction indicator light is commanded to be illuminated but is not, the vehicle shall fail the on-board diagnostic inspection.
(4)
If the malfunction indicator light (MIL) does not illuminate at all when the vehicle is in the key-on/engine-off (KOEO) condition, the vehicle shall fail the on-board diagnostic inspection, even if no DTCs are present and the MIL has not been commanded on.
Code of Federal Regulations
(a)
Motorists whose vehicles fail the on-board diagnostic test described in § 85.2222 shall be provided with the on-board diagnostic test results, including the codes retrieved, the name of the component or system associated with each fault code, the status of the MIL illumination command, and the customer alert statement as stated in paragraph (c) of this section.
(c)
In addition to any codes which were retrieved, the test report shall include the following language:
Your vehicle's computerized self-diagnostic system (OBD) registered the fault(s) listed below. This fault(s) is probably an indication of a malfunction of an emission component. However, multiple and/or seemingly unrelated faults may be an indication of an emission-related problem that occurred previously but upon further evaluation by the OBD system was determined to be only temporary. Therefore, proper diagnosis by a qualified technician is required to positively identify the source of any emission-related problem.
Code of Federal Regulations
(a) Applicability.
The requirements of this subsection apply to short tests conducted under Emissions Performance Warranty through December 31, 1993. The requirements of § 85.2225 apply concurrently until December 31, 1993, after which the requirements of § 85.2225 are solely in effect. The following exceptions apply: In a state where the Administrator has approved a SIP revision providing for implementation of a basic centralized program meeting the requirements of part 51, subpart S of this chapter, according to the schedule specified in § 51.373 of this chapter, the requirements of this section are concurrently in effect until June 30, 1994 for 1995 and earlier model year vehicles or engines; in a state where the Administrator has approved a SIP revision providing for implementation of an enhanced program meeting the requirements of part 51, subpart S of this chapter, according to the schedule specified in § 51.373 of this chapter, the requirements of this section are concurrently in effect until December 31, 1995 for 1995 and earlier model year vehicles or engines.
(b) Sampling system—
(1) General requirements.
The exhaust sampling system shall consist of a sample probe, moisture separator and analyzers for HC and CO.
(2) Dual sample probe requirements.
If used, a dual sample probe must provide equal flow in each leg. The equal flow criterion is considered to be met if the flow rate in each leg of the probe (or an identical model) has been measured under two sample flow rates (the normal rate and a rate equal to the onset of low flow), and if the flow rates in each of the legs are found to be equal to each other (±15%).
(c) Analyzers—
(1) Accuracy.
The HC analyzer shall have an accuracy of ±15 ppm at 200 to 220 ppm concentration HC (as hexane). The CO analyzer shall have an accuracy of ±0.1% CO from 1.0% to 1.2% concentration.
(3) Drift.
Analyzer drift (up-scale and down-scale zero and span wander) shall not exceed ±0.1% CO and ±15 ppm HC (as hexane) on the lowest range capable of reading 1.0% or 200 ppm HC (as hexane) during a one-hour period.
Code of Federal Regulations
(a) Special calendar and model year applicability.
The requirements of § 85.2224 apply concurrently for tests conducted under Emission Performance Warranty on 1995 and earlier model year vehicles or engines until December 31, 1993, after which the requirements of this section are solely in effect. The following exceptions apply: in a state where the Administrator has approved a SIP revision providing for implementation of a basic centralized program meeting the requirements of part 51, subpart S of this chapter, according to the schedule specified in § 51.373 of this chapter, the requirements of § 85.2224 are concurrently in effect until June 30, 1994, for 1995 and earlier model year vehicles or engines; in a state where the Administrator has approved a SIP revision providing for implementation of an enhanced program meeting the requirements of part 51, subpart S of this chapter, according to the schedule specified in § 51.373 of this chapter, the requirements of § 85.2224 are concurrently in effect until December 31, 1995, for 1995 and earlier model year vehicles or engines.
(b) Sampling System—
(1) General requirements.
The sampling system for steady state short tests consists, at a minimum, of a tailpipe probe; a flexible sample line; a water removal system; particulate trap; sample pump; flow control components; tachometer or dynamometer; analyzers for HC, CO, and CO2; and digital displays for exhaust concentrations of HC, CO, and CO2; and for engine rpm. Materials that are in contact with the gases sampled may not contaminate or change the character of the gases to be analyzed, including gases from alcohol-fueled vehicles. The probe must be capable of being inserted to a depth of at least ten inches into the tailpipe of the vehicle being tested or into an extension boot, if one is used. A digital display for dynamometer speed and load must be included if the test procedures described in § 85.2217 or § 85.2219 are conducted. Minimum specifications for optional NO analyzers are also described in this section. The analyzer system must be able to test, as specified in §§ 85.2213, 85.2215, 85.2217, 85.2218, 85.2219, and 85.2220 all model vehicles in service at the time of sale of the analyzer.
(2) Temperature operating range.
The sampling system and all associated hardware must be of a design certified to operate within the performance specifications described in paragraph (c) of this section in ambient air temperatures ranging from 41 to 110 °F. The analyzer system must, where necessary, include features to keep the sampling system within the specified range.
(3) Humidity operating range.
The sampling system and all associated hardware must be of a design certified to operate within the performance specifications described in paragraph (c) of this section at a minimum of 80 percent relative humidity throughout the required temperature range.
(4) Barometric pressure compensation.
Barometric pressure compensation must be provided. Compensation is made for elevations up to 6000 feet (above mean sea level). At any given altitude and ambient conditions specified in paragraphs (b) (2) and (3) of this section, errors due to barometric pressure changes of ±2 inches of mercury may not exceed the accuracy limits specified in paragraph (c) of this section.
(5) Dual sample probe requirements.
When testing a vehicle with dual exhaust pipes, a dual sample probe of a design certified by the analyzer manufacturer to provide equal flow in each leg must be used. The equal flow requirement is considered to be met if the flow rate in each leg of the probe has been measured under two sample pump flow rates (the normal rate and a rate equal to the onset of low flow), and if the flow rates in each of the legs are found to be equal to each other (within 15 percent of the flow rate in the leg having lower flow).
(6) System lockout during warmup.
Functional operation of the gas sampling unit must remain disabled through a system lockout until the instrument meets stability and warmup requirements. The instrument is considered “warmed up” when the zero and span readings for HC, CO, and CO2 have stabilized, within ±3 percent of the full range of low scale, for five minutes without adjustment.
(7) Electromagnetic isolation and interference.
Electromagnetic signals found in an automotive service environment may not cause malfunctions or changes in the accuracy in the electronics of the analyzer system. The instrument design must ensure that readings do not vary as a result of electromagnetic radiation and induction devices normally found in the automotive service environment, including high energy vehicle ignition systems, radio frequency transmission radiation sources, and building electrical systems.
(8) Vibration and shock protection.
System operation must be unaffected by the vibration and shock encountered under the normal operating conditions encountered in an automotive service environment.
(9) Propane Equivalency Factor.
The Propane Equivalency Factor must be displayed in a manner that enables it to be viewed conveniently, while permitting it to be altered only by personnel specifically authorized to do so.
(c) Analyzers—
(1) Accuracy.
The analyzers must be of a design certified to meet the following accuracy requirements when calibrated to the span points specified in § 85.2233(e)(2) :
| Channel | Range | Accuracy | Noise | Repeatability |
|---|---|---|---|---|
| HC, as hexane | 0-400 ±12 | 6 | 8 | |
| 401-1000 ±30 | 10 | 15 | ||
| 1001-2000 ±80 | 20 | 30 | ||
| CO, % | 0-2.00 ±0.06 | 0.02 | 0.03 | |
| 2.01-5.00 ±0.15 | .06 | .08 | ||
| 5.01-9.99 ±0.40 | .10 | .15 | ||
| CO2, % | 0-4.0 ±0.6 | .2 | .3 | |
| 4.1-14.0 ±0.5 | .2 | .3 | ||
| 14.1-16.0 ±0.6 | .2 | .3 | ||
| NO, ppm | 0-1000 ±32 | 16 | 20 | |
| 1001-2000 ±60 | 25 | 30 | ||
| 2001-4000 ±120 | 50 | 60 |
(2) Minimum analyzer display resolution.
The analyzer electronics must have sufficient resolution to achieve the level of accuracy indicated in paragraphs (c)(2)(i) through (v) of this section.
(3) Response time.
The response time from the probe to the display for HC, CO, and CO2 analyzers may not exceed eight seconds to 90 percent of a step change in input. For NO analyzers, the response time may not exceed twelve seconds to 90 percent of a step change in input.
(4) Display refresh rate.
Dynamic information being displayed must be refreshed at a minimum rate of twice per second.
(5) Interference effects.
The interference effects for non-interest gases may not exceed ±10 ppm for hydrocarbons, ±0.05 percent for carbon monoxide, ±0.20 percent for carbon dioxide, and ±20 ppm for oxides of nitrogen.
(6) Low flow indication.
The analyzer must provide an indication when the sample flow is below the acceptable level. The sampling system must be equipped with a flow meter (or equivalent) that indicates sample flow degradation when meter error exceeds three percent of full scale, or causes system response time to exceed 13 seconds to 90 percent of a step change in input, whichever is less.
(7) Engine speed detection.
The analyzer must utilize a tachometer capable of detecting engine speed in revolutions per minute (rpm) with a 0.5 second response time and an accuracy of ±3 percent of the true rpm.
(8) Test and mode timers.
The analyzer must be capable of simultaneously determining the amount of time elapsed in a test, and in a mode within that test.
(9) Sample rate.
The analyzer must be capable of measuring exhaust concentrations of gases specified in this section at a minimum rate of once every 0.75 second.
(d) Demonstration of conformity.
The analyzer must be demonstrated to the satisfaction of the inspection program manager, through acceptance testing procedures, to meet the requirements of this section and to be capable of being maintained as required in § 85.2233.
Code of Federal Regulations
(a) Applicability.
The requirements of this subsection apply to short tests conducted under Emissions Performance Warranty through December 31, 1993. The requirements of § 85.2230 apply concurrently until December 31, 1993, after which the requirements of § 85.2230 are solely in effect. The following exceptions apply: in a state where the Administrator has approved a SIP revision providing for implementation of a basic centralized program meeting the requirements of part 51, subpart S of this chapter, according to the schedule specified in § 51.373 of this chapter, the requirements of this section are concurrently in effect until June 30, 1994 for 1995 and earlier model year vehicles or engines; in a state where the Administrator has approved a SIP revision providing for implementation of an enhanced program meeting the requirements of part 51, subpart S of this chapter, according to the schedule specified in § 51.373 of this chapter, the requirements of this section are concurrently in effect until December 31, 1995 for 1995 and earlier model year vehicles or engines.
(c)
Speed shall be measured from the dynamometer roll(s) with an accuracy of ±1.5 mph at 30 mph true roll speed.