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Proposed OBD regulations for 8,500-14,000 pound highway diesel
applications & >14,000 pound highway diesel and gasoline applications

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Tutorial on the OBD regulations in 40 CFR Part 86

Engine certification versus Chassis certification

40 CFR part 86, subpart A contains requirements for engine certified
systems.

40 CFR part 86, subpart S contains requirements for chassis certified
systems.

- light-duty & heavy-duty chassis certs (i.e., “heavy as light”,
“HD complete vehicle”).

- That is, if it’s chassis certified, you need to refer to subpart S
first, NOT subpart A

Section (§) numbering

Subpart A (engine cert) and Subpart S (chassis cert) use different
Section numbering conventions, as discussed below.

Subpart A (engine cert) section numbering convention

OBD requirements for <14K pounds are contained in sections numbered as
follows:  §86.0XX-17 and §86.0XX-30, where XX represents the Model
Year of applicability.

Example:

§86.007-17 contains OBD requirements for 2007 and later model years;
§86.007-30 contains OBD certification requirements for 2007 and later
model years.  These requirements apply to subsequent model years unless
superceded (e.g., §86.010-17, for the 2010 and later model years,
supercedes §86.007-17).

Subpart S (chassis cert) section numbering convention

OBD requirements for any chassis certified system, regardless of weight,
are contained in sections numbered as follows:  §86.1806-XX where XX
represents the Model Year of applicability.

Example:

§86.1806-07 contains OBD requirements for 2007 and later model years.
These requirements apply to subsequent model years unless superceded
(e.g., §86.1806-10, for the 2010 and later model years, supercedes
§86.1806-07).

Newly added section for >14K OBD

OBD requirements for >14K pounds are contained in a newly added section
within subpart A, §86.0XX-18.  For >14K OBD, all OBD requirements are
in subpart A since all >14K pound OBD will be engine certified.

Example:

§86.010-18 contains requirements for 2010+ MYs

§86.013-18 contains requirements for 2013+ MYs

§86.016-18 contains requirements for 2016+ MYs

§86.019-18 contains requirements for 2019+ MYs

All of these sections have been added because of proposed changes to the
requirements in 2013, 2016, and 2019.

Superceding sections and all the “[Reserved]” text

The text that appears in superceding sections represents the text that
is being changed.  Text that has NOT changed relative to earlier
sections is denoted by “[Reserved.] For guidance see…”  This
convention is meant to make it easier to see what is being changed.

PART 86 CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND
ENGINES

§ 86.1 Reference materials.

*	*	*	*	*

(b)	*	*	*

(2)	 *	*	*

Document No. and name	40 CFR part 86 reference

*            *              *            *

SAE J1930, Electrical/Electronic Systems Diagnostic Terms, Definitions,
Abbreviations, and Acronyms_Equivalent to ISO/TR 15031-2: April 2002.

*       *      *

86.010-18

SAE J1939, MONTH 2006, Recommended Practice for a Serial Control and
Communications Vehicle Network.	86.010-18; 86.010-38

SAE J1939-13, MONTH 2006, Off-Board Diagnostic Connector.	86.013-18

SAE J1962, Diagnostic Connector – Equivalent to ISO/DIS 15031-3: April
2002	86.013-18

SAE J1978, OBD II Scan Tool_Equivalent to ISO/DIS 15031-4: April 2002.
86.010-18

SAE J1979, E/E Diagnostic Test Modes – Equivalent to ISO/DIS 15031-5:
April 2002.	86.010-18; 86.010-38

SAE J2012, Diagnostic Trouble Code Definitions – Equivalent to ISO/DIS
15031-6:April 2002	86.010-18

SAE J2403, Medium/Heavy-Duty E/E Systems Diagnosis Nomenclature; August
2004	86.007-17; 86.010-18; 86.010-38; 86.1806-07

SAE J2534, Recommended Practice for Pass-Thru Vehicle Reprogramming:
February 2002	86.010-18; 86.010-38

*	*	*	*	*

(5) *	*	*

Document No. and name	40 CFR part 86 reference

*            *            *            *

ISO 15765-4:2001, Road Vehicles-Diagnostics on Controller Area Network
(CAN) - Part 4: Requirements for emission-related systems: December
2001.

*      *      *

86.010-18

*	*	*	*	*

Proposed OBD Regulations in Subpart A

§ 86.007-17 On-board Diagnostics for engines used in applications less
than or equal to 14,000 pounds GVWR.

Section 86.007–17 includes text that specifies requirements that
differ from §86.005–17. Where a paragraph in §86.005–17 is
identical and applicable to §86.007–17, this may be indicated by
specifying the corresponding paragraph and the statement “[Reserved].
For guidance see §86.005–17.”

(a) General

(a)(1) [Reserved]. For guidance see §86.005–17.

(a)(2) An OBD system demonstrated to fully meet the requirements in
§86.1806–07 may be used to meet the requirements of this section,
provided that the Administrator finds that a manufacturer’s decision
to use the flexibility in this paragraph (a)(2) is based on good
engineering judgment.

(b) Malfunction descriptions

(b) introductory text and (b)(1)(i) [Reserved]. For guidance see
§86.005–17.

(b)(1)(ii)  Diesel.

(b)(1)(ii)(A) If equipped, catalyst deterioration or malfunction before
it results in exhaust NOx emissions exceeding either:  1.75 times the
applicable NOx standard for engines certified to a NOx FEL greater than
0.50 g/bhp-hr; or, the applicable NOx FEL+0.5 g/bhp-hr for engines
certified to a NOx FEL less than or equal to 0.50 g/bhp-hr.  This
requirement applies only to reduction catalysts; monitoring of oxidation
catalysts is not required. This monitoring need not be done if the
manufacturer can demonstrate that deterioration or malfunction of the
system will not result in exceedance of the threshold.

(b)(1)(ii)(B) and (b)(2) [Reserved]. For guidance see §86.005–17.

(b)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of
aftertreatment devices.

(b)(3)(i)(A) Otto-cycle. If equipped, sensor deterioration or
malfunction resulting in exhaust emissions exceeding 1.5 times the
applicable standard or FEL for NMHC, NOx or CO.

(b)(3)(i)(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NOx standard for engines certified
to a NOx FEL greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5
g/bhp-hr for engines certified to a NOx FEL less than or equal to 0.50
g/bhp-hr; or, 2.5 times the applicable NMHC standard.

(b)(3)(ii) Oxygen sensors and air-fuel ratio sensors upstream of
aftertreatment devices.

(b)(3)(ii)(A) Otto-cycle. If equipped, sensor deterioration or
malfunction resulting in exhaust emissions exceeding 1.5 times the
applicable standard or FEL for NMHC, NOx or CO.

(b)(3)(ii)(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NOx standard for engines certified
to a NOx FEL greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5
g/bhp-hr for engines certified to a NOx FEL less than or equal to 0.50
g/bhp-hr; or, 2.5 times the applicable NMHC standard; or, 2.5 times the
applicable CO standard.

(b)(3)(iii) NOx sensors.

(b)(3)(iii)(A) Otto-cycle. If equipped, sensor deterioration or
malfunction resulting in exhaust emissions exceeding 1.5 times the
applicable standard or FEL for NMHC, NOx or CO.

(b)(3)(iii)(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NOx standard for engines certified
to a NOx FEL greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5
g/bhp-hr for engines certified to a NOx FEL less than or equal to 0.50
g/bhp-hr.

(b)(4) [Reserved]. For guidance see §86.005–17.

(b)(5) Other emission control systems and components.

(b)(5)(i) Otto-cycle. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas recirculation
(EGR) system, if equipped, the secondary air system, if equipped, and
the fuel control system, singularly resulting in exhaust emissions
exceeding 1.5 times the applicable emission standard or FEL for NMHC,
NOx or CO. For engines equipped with a secondary air system, a
functional check, as described in §86.005-17(b)(6), may satisfy the
requirements of this paragraph (b)(5) provided the manufacturer can
demonstrate that deterioration of the flow distribution system is
unlikely. This demonstration is subject to Administrator approval and,
if the demonstration and associated functional check are approved, the
diagnostic system must indicate a malfunction when some degree of
secondary airflow is not detectable in the exhaust system during the
check. For engines equipped with positive crankcase ventilation (PCV),
monitoring of the PCV system is not necessary provided the manufacturer
can demonstrate to the Administrator’s satisfaction that the PCV
system is unlikely to fail.

(b)(5)(ii) Diesel. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas recirculation
(EGR) system, if equipped, and the fuel control system, singularly
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NOx standard for engines certified
to a NOx FEL greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5
g/bhp-hr for engines certified to a NOx FEL less than or equal to 0.50
g/bhp-hr; or, 2.5 times the applicable NMHC standard; or, 2.5 times the
applicable CO standard. A functional check, as described in
§86.005-17(b)(6), may satisfy the requirements of this paragraph (b)(5)
provided the manufacturer can demonstrate that a malfunction would not
cause emissions to exceed the applicable levels. This demonstration is
subject to Administrator approval. For engines equipped with crankcase
ventilation (CV), monitoring of the CV system is not necessary provided
the manufacturer can demonstrate to the Administrator’s satisfaction
that the CV system is unlikely to fail.

(b)(6) [Reserved]. For guidance see §86.005–17.

(b)(7) Performance of OBD functions. Any sensor or other component
deterioration or malfunction which renders that sensor or component
incapable of performing its function as part of the OBD system must be
detected and identified on engines so equipped.

(c) through (h)

(c), (d), (e), (f), (g), and (h)(1)(i) through (h)(1)(iv) [Reserved].
For guidance see §86.005–17.

(h)(1)(v) All acronyms, definitions and abbreviations shall be formatted
according to SAE J1930 “Electrical/Electronic Systems Diagnostic
Terms, Definitions, Abbreviations, and Acronyms” Equivalent to ISO/TR
15031–2: April 30, 2002”, (Revised, April 2002), or SAE J2403,
“Medium/Heavy-Duty E/E Systems Diagnosis Nomenclature: August 2004.”

(h)(1)(vi) through (h)(3) [Reserved]. For guidance see §86.005–17.

(i) Deficiencies

(i) Deficiencies and alternative fueled engines. Upon application by the
manufacturer, the Administrator may accept an OBD system as compliant
even though specific requirements are not fully met. Such compliances
without meeting specific requirements, or deficiencies, will be granted
only if compliance would be infeasible or unreasonable considering such
factors as, but not limited to: technical feasibility of the given
monitor and lead time and production cycles including phase-in or
phase-out of engines or vehicle designs and programmed upgrades of
computers. Unmet requirements should not be carried over from the
previous model year except where unreasonable hardware or software
modifications would be necessary to correct the deficiency, and the
manufacturer has demonstrated an acceptable level of effort toward
compliance as determined by the Administrator. Furthermore, EPA will not
accept any deficiency requests that include the complete lack of a major
diagnostic monitor (“major” diagnostic monitors being those for
exhaust aftertreatment devices, oxygen sensor, air-fuel ratio sensor,
NOx sensor, engine misfire, evaporative leaks, and diesel EGR, if
equipped), with the possible exception of the special provisions for
alternative fueled engines. For alternative fueled heavy-duty engines
(e.g. natural gas, liquefied petroleum gas, methanol, ethanol),
manufacturers may request the Administrator to waive specific monitoring
requirements of this section for which monitoring may not be reliable
with respect to the use of the alternative fuel. At a minimum,
alternative fuel engines must be equipped with an OBD system meeting OBD
requirements to the extent feasible as approved by the Administrator.

(j) CARB OBDII compliance option

(j) California OBDII compliance option. For heavy-duty engines used in
applications weighing 14,000 pounds GVWR or less, demonstration of
compliance with California OBD II requirements (Title 13 California Code
of Regulations section 1968.2 (13 CCR 1968.2)), as modified and released
on August 11, 2006, shall satisfy the requirements of this section,
except that compliance with 13 CCR 1968.2(e)(4.2.2)(C), pertaining to
0.02 inch evaporative leak detection, and 13 CCR 1968.2(d)(1.4),
pertaining to tampering protection, are not required to satisfy the
requirements of this section. Also, the deficiency provisions of 13 CCR
1968.2(k) do not apply. The deficiency provisions of paragraph (i) of
this section and the evaporative leak detection requirement of
§86.005-17(b)(4) apply to manufacturers selecting this paragraph for
demonstrating compliance. In addition, demonstration of compliance with
13 CCR 1968.2(e)(15.2.1)(C), to the extent it applies to the
verification of proper alignment between the camshaft and crankshaft,
applies only to vehicles equipped with variable valve timing.

(k) [Reserved]. For guidance see §86.005–17.

§ 86.007-30	Certification.

Section 86.007–30 includes text that specifies requirements that
differ from §§86.094–30, 86.095–30, 86.096–30, 86.098–30,
86.001–30 or 86.004–30. Where a paragraph in §86.094–30,
§86.095–30, §86.096–30, §86.098–30, §86.001–30 or
§86.004–30 is identical and applicable to §86.007–30, this may be
indicated by specifying the corresponding paragraph and the statement
“[Reserved]. For guidance see §86.094–30.” or “[Reserved]. For
guidance see §86.095–30.” or “[Reserved]. For guidance see
§86.096–30.” or “[Reserved]. For guidance see §86.098–30.”
or “[Reserved]. For guidance see §86.001–30.” or “[Reserved].
For guidance see 86.004–30.”

(a) thru (e)

(a)(1) and (a)(2) [Reserved]. For guidance see §86.094–30.

(a)(3)(i) through (a)(4)(ii) [Reserved]. For guidance see §86.004-30.

(a)(4)(iii) introductory text through (a)(4)(iii)(C) [Reserved]. For
guidance see §86.094–30.

(a)(4)(iv) introductory text [Reserved]. For guidance see §86.095–30.

(a)(4)(iv)(A)–(a)(9) [Reserved]. For guidance see §86.094–30.

(a)(10) and (a)(11) [Reserved]. For guidance see §86.004-30.

(a)(12) [Reserved]. For guidance see §86.094–30.

(a)(13) [Reserved]. For guidance see §86.095–30.

(a)(14) [Reserved]. For guidance see §86.094–30.

(a) (15)–(18) [Reserved]. For guidance see §86.096–30.

(a)(19) [Reserved]. For guidance see §86.098–30.

(a)(20) [Reserved]. For guidance see §86.001–30.

(a)(21) [Reserved]. For guidance see §86.004-30.

(b)(1) introductory text through (b)(1)(ii)(A) [Reserved]. For guidance
see §86.094–30.

(b)(1)(ii)(B) [Reserved]. For guidance see §86.004-30.

(b)(1)(ii)(C) [Reserved]. For guidance see §86.094–30.

(b)(1)(ii)(D) [Reserved]. For guidance see §86.004-30.

(b)(1)(iii) and (b)(1)(iv) [Reserved]. For guidance see §86.094–30.

(b)(2) [Reserved]. For guidance see §86.098–30.

(b)(3)–(b)(4)(i) [Reserved]. For guidance see §86.094–30.

(b)(4)(ii) introductory text [Reserved]. For guidance see §86.098–30.

(b)(4)(ii)(A) [Reserved]. For guidance see §86.094–30.

(b)(4)(ii)(B)–(b)(4)(iv) [Reserved]. For guidance see §86.098–30.

(b)(5)–(e) [Reserved]. For guidance see §86.094–30.

(f) OBD certification

(f) introductory text through (f)(1)(i) [Reserved]. For guidance see
§86.004-30.

(f)(1)(ii) Diesel.

(f)(1)(ii)(A) If monitored for emissions performance—a catalyst is
replaced with a deteriorated or defective catalyst, or an electronic
simulation of such, resulting in exhaust emissions exceeding 1.75 times
the applicable NOx standard for engines certified to a NOx FEL greater
than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5 g/bhp-hr for engines
certified to a NOx FEL less than or equal to 0.50 g/bhp-hr.  This
requirement applies only to reduction catalysts.

(f)(1)(ii)(B) If monitored for performance—a particulate trap is
replaced with a trap that has catastrophically failed, or an electronic
simulation of such.

(f)(2) [Reserved]. For guidance see §86.004-30.

(f)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of
aftertreatment devices.

(f)(3)(i)(A) Otto-cycle. If so equipped, any oxygen sensor or air-fuel
ratio sensor located downstream of aftertreatment devices is replaced
with a deteriorated or defective sensor, or an electronic simulation of
such, resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NOx or CO.

(f)(3)(i)(B) Diesel. If so equipped, any oxygen sensor or air-fuel ratio
sensor located downstream of aftertreatment devices is replaced with a
deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NOx standard for engines certified
to a NOx FEL greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5
g/bhp-hr for engines certified to a NOx FEL less than or equal to 0.50
g/bhp-hr; or, 2.5 times the applicable NMHC standard.

(f)(3)(ii) Oxygen sensors and air-fuel ratio sensors upstream of
aftertreatment devices.

(f)(3)(ii)(A) Otto-cycle. If so equipped, any oxygen sensor or air-fuel
ratio sensor located upstream of aftertreatment devices is replaced with
a deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NOx or CO.

(f)(3)(ii)(B) Diesel. If so equipped, any oxygen sensor or air-fuel
ratio sensor located upstream of aftertreatment devices is replaced with
a deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NOx standard for engines certified
to a NOx FEL greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5
g/bhp-hr for engines certified to a NOx FEL less than or equal to 0.50
g/bhp-hr; or, 2.5 times the applicable NMHC standard; or, 2.5 times the
applicable CO standard.

(f)(3)(iii) NOx sensors.

(f)(3)(iii)(A) Otto-cycle. If so equipped, any NOx sensor is replaced
with a deteriorated or defective sensor, or an electronic simulation of
such, resulting in exhaust emissions exceeding 1.5 times the applicable
standard or FEL for NMHC, NOx or CO.

(f)(3)(iii)(B) Diesel. If so equipped, any NOx sensor is replaced with a
deteriorated or defective sensor, or an electronic simulation of such,
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, 1.75 times the applicable NOx standard for engines certified
to a NOx FEL greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5
g/bhp-hr for engines certified to a NOx FEL less than or equal to 0.50
g/bhp-hr.

(f)(4) [Reserved]. For guidance see §86.004-30.

(f)(5)(i) Otto-cycle. A malfunction condition is induced in any
emission-related engine system or component, including but not
necessarily limited to, the exhaust gas recirculation (EGR) system, if
equipped, the secondary air system, if equipped, and the fuel control
system, singularly resulting in exhaust emissions exceeding 1.5 times
the applicable emission standard or FEL for NMHC, NOx, or CO.

(f)(5)(ii) Diesel. A malfunction condition is induced in any
emission-related engine system or component, including but not
necessarily limited to, the exhaust gas recirculation (EGR) system, if
equipped, and the fuel control system, singularly resulting in exhaust
emissions exceeding any of the following levels: the applicable PM
FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is higher; or, 1.75
times the applicable NOx standard for engines certified to a NOx FEL
greater than 0.50 g/bhp-hr; or, the applicable NOx FEL+0.5 g/bhp-hr for
engines certified to a NOx FEL less than or equal to 0.50 g/bhp-hr; or,
2.5 times the applicable NMHC standard; or, 2.5 times the applicable CO
standard.

(f)(6) [Reserved]. For guidance see §86.004-30.

§ 86.010-2   Definitions.

The definitions of §86.004–2 continue to apply to 2004 and later
model year vehicles. The definitions listed in this section apply
beginning with the 2010 model year.

Drive cycle or driving cycle means operation that consists of engine
startup and engine shutoff during which a given onboard diagnostic (OBD)
monitor makes a diagnostic decision.  A drive cycle need not consist of
all OBD monitors making a diagnostic decision during the engine startup
and engine shutoff cycle.  An engine restart following an engine shutoff
that has been neither commanded by the vehicle operator nor by the
engine control strategy but caused by an event such as an engine stall
may be considered a new drive cycle or a continuation of the existing
drive cycle.

DTC means diagnostic trouble code.

Engine start as used in §86.010-18 means the point when the engine
reaches a speed 150 rpm below the normal, warmed-up idle speed (as
determined in the drive position for vehicles equipped with an automatic
transmission).  For hybrid vehicles or for engines employing alternative
engine start hardware or strategies (e.g., integrated starter and
generators.), the manufacturer may use an alternative definition for
engine start (e.g., key-on) provided the alternative definition is based
on equivalence to an engine start for a conventional vehicle.

Functional check, in the context of onboard diagnostics, means verifying
that a component and/or system that receives information from a control
computer responds properly to a command from the control computer.

Ignition cycle as used in §86.010-18 means a cycle that begins with
engine start, meets the engine start definition for at least two seconds
plus or minus one second, and ends with engine shutoff.

Limp-home operation as used in §86.010-18 means an operating mode that
an engine is designed to enter upon determining that normal operation
cannot be maintained. In general, limp-home operation implies that a
component or system is not operating properly or is believed to be not
operating properly.

Malfunction means the conditions have been met that require the
activation of an OBD malfunction indicator light and storage of a DTC.

MIL-on DTC means the diagnostic trouble code stored when an OBD system
has detected and confirmed that a malfunction exists (e.g., typically on
the second drive cycle during which a given OBD monitor has evaluated a
system or component).  Industry standards may refer to this as a
confirmed or an active DTC.

Pending DTC means the diagnostic trouble code stored upon the detection
of a potential malfunction.

Permanent DTC means a DTC that corresponds to a MIL-on DTC and is stored
in non-volatile random access memory (NVRAM).  A permanent DTC can only
be erased by the OBD system itself and cannot be erased through human
interaction with the OBD system or any onboard computer.

Previous-MIL-on DTC means a DTC that corresponds to a MIL-on DTC but is
distinguished by representing a malfunction that the OBD system has
determined no longer exists but for which insufficient operation has
occurred to satisfy the DTC erasure provisions.

Potential malfunction means that conditions have been detected that meet
the OBD malfunction criteria but for which more drive cycles are allowed
to provide further evaluation prior to confirming that a malfunction
exists.

Rationality check, in the context of onboard diagnostics, means
verifying that a component that provides input to a control computer
provides an accurate input to the control computer while in the range of
normal operation and when compared to all other available information.

Similar conditions, in the context of onboard diagnostics, means engine
conditions having an engine speed within 375 rpm, load conditions within
20 percent, and the same warm up status (i.e., cold or hot). The
manufacturer may use other definitions of similar conditions based on
comparable timeliness and reliability in detecting similar engine
operation.

§ 86.010-17 On-board Diagnostics for engines used in applications less
than or equal to 14,000 pounds GVWR.

Section 86.010–17 includes text that specifies requirements that
differ from §86.005–17 and §86.007–17. Where a paragraph in
§86.005–17 or §86.007–17 is identical and applicable to
§86.010–17, this may be indicated by specifying the corresponding
paragraph and the statement “[Reserved]. For guidance see
§86.005–17.” or “[Reserved]. For guidance see §86.007–17.”

(a) General

(a) General.

(a)(1) All heavy-duty engines intended for use in a heavy-duty vehicle
weighing 14,000 pounds GVWR or less must be equipped with an on-board
diagnostic (OBD) system capable of monitoring all emission-related
engine systems or components during the applicable useful life. All
monitored systems and components must be evaluated periodically, but no
less frequently than once per applicable certification test cycle as
defined in Appendix I, paragraph (f), of this part, or similar trip as
approved by the Administrator.

(a)(2) An OBD system demonstrated to fully meet the requirements in
§86.1806–10 may be used to meet the requirements of this section,
provided that the Administrator finds that a manufacturer’s decision
to use the flexibility in this paragraph (a)(2) is based on good
engineering judgment.

(b) Malfunction descriptions

(b) introductory text and  (b)(1)(i) [Reserved]. For guidance see
§86.005–17.

(b)(1)(ii) Diesel.

(b)(1)(ii)(A) If equipped, reduction catalyst deterioration or
malfunction before it results in exhaust NOx emissions exceeding the
applicable NOx FEL+0.3 g/bhp-hr.  If equipped, oxidation catalyst
deterioration or malfunction before it results in exhaust NMHC emissions
exceeding 2.5 times the applicable NMHC standard. These catalyst
monitoring requirements need not be done if the manufacturer can
demonstrate that deterioration or malfunction of the system will not
result in exceedance of the threshold.

(b)(1)(ii)(B) If equipped, diesel particulate trap deterioration or
malfunction before it results in exhaust emissions exceeding any of the
following levels: the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr
PM, whichever is higher; or, exhaust NMHC emissions exceeding 2.5 times
the applicable NMHC standard.  Catastrophic failure of the particulate
trap must also be detected.  In addition, the absence of the particulate
trap or the trapping substrate must be detected.

(b)(2) [Reserved]. For guidance see §86.005–17.

(b)(3)(i) Oxygen sensors and air-fuel ratio sensors downstream of
aftertreatment devices.

(b)(3)(i)(A) Otto-cycle. If equipped, sensor deterioration or
malfunction resulting in exhaust emissions exceeding 1.5 times the
applicable standard or FEL for NMHC, NOx or CO.

(b)(3)(i)(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, the applicable NOx FEL+0.3 g/bhp-hr; or, 2.5 times the
applicable NMHC standard.

(b)(3)(ii) Oxygen sensors and air-fuel ratio sensors upstream of
aftertreatment devices.

(b)(3)(ii)(A) Otto-cycle. If equipped, sensor deterioration or
malfunction resulting in exhaust emissions exceeding 1.5 times the
applicable standard or FEL for NMHC, NOx or CO.

(b)(3)(ii)(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is
higher; or, the applicable NOx FEL+0.3 g/bhp-hr; or, 2.5 times the
applicable NMHC standard; or, 2.5 times the applicable CO standard.

(b)(3)(iii) NOx sensors.

(b)(3)(iii)(A) Otto-cycle. If equipped, sensor deterioration or
malfunction resulting in exhaust emissions exceeding 1.5 times the
applicable standard or FEL for NMHC, NOx or CO.

(b)(3)(iii)(B) Diesel. If equipped, sensor deterioration or malfunction
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.04 g/bhp-hr or 0.05 g/bhp-hr PM, whichever is
higher; or, the applicable NOx FEL+0.3 g/bhp-hr.

(b)(4) [Reserved]. For guidance see §86.005–17.

(b)(5) Other emission control systems and components.

(b)(5)(i) Otto-cycle. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas recirculation
(EGR) system, if equipped, the secondary air system, if equipped, and
the fuel control system, singularly resulting in exhaust emissions
exceeding 1.5 times the applicable emission standard or FEL for NMHC,
NOx or CO. For engines equipped with a secondary air system, a
functional check, as described in §86.005-17(b)(6), may satisfy the
requirements of this paragraph (b)(5) provided the manufacturer can
demonstrate that deterioration of the flow distribution system is
unlikely. This demonstration is subject to Administrator approval and,
if the demonstration and associated functional check are approved, the
diagnostic system must indicate a malfunction when some degree of
secondary airflow is not detectable in the exhaust system during the
check. For engines equipped with positive crankcase ventilation (PCV),
monitoring of the PCV system is not necessary provided the manufacturer
can demonstrate to the Administrator’s satisfaction that the PCV
system is unlikely to fail.

(b)(5)(ii) Diesel. Any deterioration or malfunction occurring in an
engine system or component directly intended to control emissions,
including but not necessarily limited to, the exhaust gas recirculation
(EGR) system, if equipped, and the fuel control system, singularly
resulting in exhaust emissions exceeding any of the following levels:
the applicable PM FEL+0.02 g/bhp-hr or 0.03 g/bhp-hr PM, whichever is
higher; or, the applicable NOx FEL+0.3 g/bhp-hr; or, 2.5x the applicable
NMHC standard; or, 2.5x the applicable CO standard. A functional check,
as described in §86.005-17(b)(6), may satisfy the requirements of this
paragraph (b)(5) provided the manufacturer can demonstrate that a
malfunction would not cause emissions to exceed the applicable levels.
This demonstration is subject to Administrator approval. For engines
equipped with crankcase ventilation (CV), monitoring of the CV system is
not necessary provided the manufacturer can demonstrate to the
Administrator’s satisfaction that the CV system is unlikely to fail.

(b)(6) [Reserved]. For guidance see §86.005–17.

(b)(7) [Reserved]. For guidance see §86.007–17.

(c) MIL

(c) [Reserved]. For guidance see §86.005–17.

(d) MIL illumination

(d) MIL illumination.

(d)(1) The MIL must illuminate and remain illuminated when any of the
conditions specified in paragraph (b) of this section are detected and
verified, or whenever the engine control enters a default or secondary
mode of operation considered abnormal for the given engine operating
conditions. The MIL must blink once per second under any period of
operation during which engine misfire is occurring and catalyst damage
is imminent. If such misfire is detected again during the following
driving cycle (i.e., operation consisting of, at a minimum, engine
start-up and engine shut-off) or the next driving cycle in which similar
conditions are encountered, the MIL must maintain a steady illumination
when the misfire is not occurring and then remain illuminated until the
MIL extinguishing criteria of this section are satisfied. The MIL must
also illuminate when the vehicle's ignition is in the “key-on”
position before engine starting or cranking and extinguish after engine
starting if no malfunction has previously been detected. If a fuel
system or engine misfire malfunction has previously been detected, the
MIL may be extinguished if the malfunction does not reoccur during three
subsequent sequential trips during which similar conditions are
encountered and no new malfunctions have been detected. Similar
conditions are defined as engine speed within 375 rpm, engine load
within 20 percent, and engine warm-up status equivalent to that under
which the malfunction was first detected. If any malfunction other than
a fuel system or engine misfire malfunction has been detected, the MIL
may be extinguished if the malfunction does not reoccur during three
subsequent sequential trips during which the monitoring system
responsible for illuminating the MIL functions without detecting the
malfunction, and no new malfunctions have been detected. Upon
Administrator approval, statistical MIL illumination protocols may be
employed, provided they result in comparable timeliness in detecting a
malfunction and evaluating system performance, i.e., three to six
driving cycles would be considered acceptable.

(d)(2) Drive cycle or driving cycle, in the context of this section
§86.010-17, the definition for drive cycle or driving cycle given in
§86.010-2 is enhanced.  A drive cycle means an OBD trip that consists
of engine startup and engine shutoff and includes the period of engine
off time up to the next engine startup.  For vehicles that employ engine
shutoff strategies (e.g., engine shutoff at idle), the manufacturer may
use an alternative definition for drive cycle (e.g., key-on followed by
key-off).  Any alternative definition must be based on equivalence to
engine startup and engine shutoff signaling the beginning and ending of
a single driving event for a conventional vehicle.  For applications
that span 14,000 pounds GVWR, the manufacturer may use the drive cycle
definition of §86.010-18 in lieu of the definition in this paragraph.

(e) thru (k)

(e), (f), (g), and (h)(1)(i) through (h)(1)(iv) [Reserved]. For guidance
see §86.005–17.

(h)(1)(v) [Reserved]. For guidance see §86.007–17.

(h)(1)(vi) through (h)(3) [Reserved]. For guidance see §86.005–17.

(i) and (j) [Reserved]. For guidance see §86.007–17.

(k) [Reserved.]

§ 86.010-18 On-board Diagnostics for engines used in applications
greater than 14,000 pounds GVWR.

(a) General

General. According to the implementation schedule shown in paragraph (o)
of this section, heavy-duty engines intended for use in a heavy-duty
vehicle weighing more than 14,000 pounds GVWR must be equipped with an
on-board diagnostic (OBD) system capable of monitoring all
emission-related engine systems or components during the life of the
engine. The OBD system is required to detect all malfunctions specified
in paragraphs (g), (h), and (i) of this section although the OBD system
is not required to use a unique monitor to detect each of those
malfunctions.

When the OBD system detects a malfunction, it must store a pending, a
MIL-on, or a previous-MIL-on diagnostic trouble code (DTC) in the
onboard computer’s memory.  A malfunction indicator light (MIL) must
also be activated as specified in paragraph (b) of this section.

The OBD system must be equipped with a data link connector to provide
access to the stored DTCs as specified in paragraph (k)(2) of this
section.

The OBD system cannot be programmed or otherwise designed to deactivate
based on age and/or mileage. This requirement does not alter existing
law and enforcement practice regarding a manufacturer’s liability for
an engine beyond its regulatory useful life, except where an engine has
been programmed or otherwise designed so that an OBD system deactivates
based on age and/or mileage of the engine.

Drive cycle or driving cycle, in the context of this section, the
definition for drive cycle or driving cycle given in §86.010-2 is
enhanced.  A drive cycle means an OBD trip that meets any of the
conditions of paragraphs (a)(4)(i) through (a)(4)(iv) of this section.
Further, for OBD monitors that run during engine-off conditions, the
period of engine-off time following engine shutoff and up to the next
engine start may be considered part of the drive cycle for the
conditions of paragraphs (a)(4)(i) and (a)(4)(iv) of this section.  For
engines/vehicles that employ engine shutoff OBD monitoring strategies
that do not require the vehicle operator to restart the engine to
continue vehicle operation (e.g., a hybrid bus with engine shutoff at
idle), the manufacturer may use an alternative definition for drive
cycle (e.g., key-on followed by key-off).  Any alternative definition
must be based on equivalence to engine startup and engine shutoff
signaling the beginning and ending of a single driving event for a
conventional vehicle.  For engines that are not likely to be routinely
operated for long continuous periods of time, a manufacturer may also
request approval to use an alternative definition for drive cycle (e.g.,
solely based on engine start and engine shutoff without regard to four
hours of continuous engine-on time).  Administrator approval of the
alternative definition will be based on manufacturer-submitted data
and/or information demonstrating the typical usage, operating habits,
and/or driving patterns of these vehicles.

Begins with engine start and ends with engine shutoff;

Begins with engine start and ends after four hours of continuous
engine-on operation;

Begins at the end of the previous four hours of continuous engine-on
operation and ends after four hours of continuous engine-on operation;
or

Begins at the end of the previous four hours of continuous engine-on
operation and ends with engine shutoff.

(b) MIL and DTCs

Malfunction indicator light (MIL) and Diagnostic Trouble Codes (DTC).
The OBD system must incorporate a malfunction indicator light (MIL) or
equivalent and must store specific types of diagnostic trouble codes
(DTC).

MIL specifications.

[Reserved.]

The OBD system must activate the MIL when the ignition is in the
key-on/engine-off position before engine cranking to indicate that the
MIL is functional.  The MIL shall be activated continuously during this
functional check for a minimum of 5 seconds.  During this MIL key-on
functional check, the data stream value (see paragraph (k)(4)(ii) of
this section) for MIL status must indicate “commanded off” unless
the OBD system has detected a malfunction and has stored a MIL-on DTC.
This MIL key-on functional check is not required during vehicle
operation in the key-on/engine-off position subsequent to the initial
engine cranking of an ignition cycle (e.g., due to an engine stall or
other non-commanded engine shutoff).

As an option, the MIL may be used to indicate readiness status (see
paragraph (k)(4)(i) of this section) in a standardized format in the
key-on/engine-off position.

A manufacturer may also use the MIL to indicate which, if any, DTCs are
currently stored (e.g., to “blink” the stored DTCs).  Such use must
not activate unintentionally during routine driver operation.

[Reserved.]

MIL activation and DTC storage protocol.

Within 10 seconds of detecting a potential malfunction, the OBD system
must store a pending DTC that identifies the potential malfunction.

If the potential malfunction is again detected before the end of the
next drive cycle during which monitoring occurs (i.e., the potential
malfunction has been confirmed as a malfunction), then within 10 seconds
of such detection the OBD system must activate the MIL continuously and
store a MIL-on DTC.  If the potential malfunction is not detected before
the end of the next drive cycle during which monitoring occurs (i.e.,
there is no indication of the malfunction at any time during the drive
cycle), the corresponding pending DTC should be erased at the end of the
drive cycle.  Similarly, if a malfunction is detected for the first time
and confirmed on a given drive cycle without need for further
evaluation, then within 10 seconds of such detection the OBD system must
activate the MIL continuously and store a MIL-on DTC.

A manufacturer may request Administrator approval to employ alternative
statistical MIL activation and DTC storage protocols to those specified
in paragraphs (b)(2)(i) and (b)(2)(ii) of this section.  Approval will
depend upon the manufacturer providing data and/or engineering
evaluations that demonstrate that the alternative protocols can evaluate
system performance and detect malfunctions in a manner that is equally
effective and timely.  Strategies requiring on average more than six
drive cycles for MIL activation will not be accepted.

The OBD system must store a “freeze frame” of the operating
conditions (as defined in paragraph (k)(4)(iii) of this section) present
upon detecting a malfunction or a potential malfunction.  In the event
that a pending DTC has matured to a MIL-on DTC, the manufacturer shall
either retain the currently stored freeze frame conditions or replace
the stored freeze frame with freeze frame conditions regarding the
MIL-on DTC. Any freeze frame stored in conjunction with any pending DTC
or MIL-on DTC should be erased upon erasure of the corresponding DTC.

If the engine enters a limp-home mode of operation that can affect
emissions or the performance of the OBD system, or in the event of a
malfunction of an onboard computer(s) itself that can affect the
performance of the OBD system, the OBD system must activate the MIL and
store a MIL-on DTC within 10 seconds to inform the vehicle operator. If
the limp-home mode of operation is recoverable (i.e., operation
automatically returns to normal at the beginning of the following
ignition cycle), the OBD system may wait to activate the MIL and store
the MIL-on DTC if the limp-home mode of operation is again entered
before the end of the next ignition cycle rather than activating the MIL
within 10 seconds on the first drive cycle during which the limp-home
mode of operation is entered.

Before the end of an ignition cycle, the OBD system must store a
permanent DTC(s) that corresponds to any stored MIL-on DTC(s).

MIL deactivation and DTC erasure protocol.

Deactivating the MIL.  Except as otherwise provided for in paragraph
(g)(6)(iv)(B) of this section for empty reductant tanks, and paragraphs
(h)(1)(iv)(F), (h)(2)(viii), and (h)(7)(iv)(B) of this section for
gasoline fuel system, misfire, and evaporative system malfunctions, once
the MIL has been activated, it may be deactivated after three subsequent
sequential drive cycles during which the monitoring system responsible
for activating the MIL functions and the previously detected malfunction
is no longer present and provided no other malfunction has been detected
that would independently activate the MIL according to the requirements
outlined in paragraph (b)(2) of this section.

Erasing a MIL-on DTC. The OBD system may erase a MIL-on DTC if the
identified malfunction has not again been detected in at least 40 engine
warm up cycles and the MIL is presently not activated for that
malfunction.  The OBD system may also erase a MIL-on DTC upon
deactivating the MIL according to paragraph (b)(3)(i) of this section
provided a previous-MIL-on DTC is stored upon erasure of the MIL-on DTC.
 The OBD system may erase a previous-MIL-on DTC if the identified
malfunction has not again been detected in at least 40 engine warm up
cycles and the MIL is presently not activated for that malfunction.

Erasing a permanent DTC. The OBD system can erase a permanent DTC only
if either of the following conditions occur:

The OBD system itself determines that the malfunction that caused the
corresponding MIL-on DTC to be stored is no longer present and is not
commanding activation of the MIL, concurrent with the requirements of
paragraph (b)(3)(i) of this section.

Subsequent to erasing the DTC information from the on-board computer
(i.e., through the use of a scan tool or a battery disconnect), the OBD
monitor for the malfunction that caused the permanent DTC to be stored
has executed the minimum number of monitoring events necessary for MIL
activation and has determined that the malfunction is no longer present.

Exceptions to MIL and DTC requirements.

If a limp-home mode of operation causes a overt indication (e.g.,
activation of a red engine shut-down warning light) such that the driver
is certain to respond and have the problem corrected, a manufacturer may
choose not to activate the MIL as required by paragraph (b)(2)(v) of
this section. Additionally, if an auxiliary emission control device has
been properly activated as approved by the Administrator, a manufacturer
may choose not to activate the MIL.

For gasoline engines, a manufacturer may choose to meet the MIL and DTC
requirements in §86.010-17 in lieu of meeting the requirements of
paragraph (b) of §86.010-18.

(c) Monitoring conditions

Monitoring conditions. The OBD system must monitor and detect the
malfunctions specified in paragraphs (g), (h), and (i) of this section
under the following general monitoring conditions.  The more specific
monitoring conditions of paragraph (d) of this section are sometimes
required according to the provisions of paragraphs (g), (h), and (i) of
this section.

As specifically provided for in paragraphs (g), (h), and (i) of this
section, the monitoring conditions for detecting malfunctions must be
technically necessary to ensure robust detection of malfunctions (e.g.,
avoid false passes and false indications of malfunctions); designed to
ensure monitoring will occur under conditions that may reasonably be
expected to be encountered in normal vehicle operation and normal
vehicle use; and, designed to ensure monitoring will occur during the
FTP transient test cycle contained in Appendix I paragraph (f), of this
part, or similar drive cycle as approved by the Administrator.

Monitoring must occur at least once per drive cycle in which the
monitoring conditions are met.

Manufacturers may request approval to define monitoring conditions that
are not encountered during the FTP cycle as required in paragraph (c)(1)
of this section.  In evaluating the manufacturer’s request, the
Administrator will consider the degree to which the requirement to run
during the FTP transient cycle restricts monitoring during in-use
operation, the technical necessity for defining monitoring conditions
that are not encountered during the FTP cycle, data and/or an
engineering evaluation submitted by the manufacturer that demonstrate
that the component/system does not normally function during the FTP,
whether monitoring is otherwise not feasible during the FTP cycle,
and/or the ability of the manufacturer to demonstrate that the
monitoring conditions satisfy the minimum acceptable in-use monitor
performance ratio requirement as defined in paragraph (d) of this
section.

(d) In-use performance tracking

In-use performance tracking. As specifically required in paragraphs (g),
(h), and (i) of this section, the OBD system must monitor and detect the
malfunctions specified in paragraphs (g), (h), and (i) of this section
according to the criteria of this paragraph (d).  The OBD system is not
required to track and report in-use performance for monitors other than
those specifically identified in paragraph (d)(1) of this section.

The manufacturer must implement software algorithms in the OBD system to
individually track and report the in-use performance of the following
monitors, if equipped, in the standardized format specified in paragraph
(e) of this section: NMHC converting catalyst (paragraph (g)(5) of this
section); NOx converting catalyst (paragraph (g)(6) of this section;
gasoline catalyst (paragraph (h)(6) of this section); exhaust gas sensor
(paragraph (g)(9) or (h)(8) of this section); evaporative system
(paragraph (h)(7) of this section); EGR system (paragraph (g)(3) or
(h)(3) of this section);  VVT system (paragraph (g)(10) or (h)(9) of
this section); secondary air system (paragraph (h)(5) of this section);
DPF system (paragraph (g)(8) of this section); boost pressure control
system (paragraph (g)(4) of this section); and, NOx adsorber system
(paragraph (g)(7) of this section).

(d)(1)(i) The manufacturer shall not use the calculated ratio specified
in paragraph (d)(2) of this section or any other indication of monitor
frequency as a monitoring condition for a monitor (e.g., using a low
ratio to enable more frequent monitoring through diagnostic executive
priority or modification of other monitoring conditions, or using a high
ratio to enable less frequent monitoring).

(d)(1)(ii) [Reserved.]

In-use performance ratio definition. For monitors required to meet the
requirements of paragraph (d) of this section, the performance ratio
must be calculated in accordance with the specifications of this
paragraph (d)(2).

The numerator of the performance ratio is defined as the number of times
a vehicle has been operated such that all monitoring conditions have
been encountered that are necessary for the specific monitor to detect a
malfunction.

The denominator is defined as the number of times a vehicle has been
operated in accordance with the provisions of paragraph (d)(4) of this
section.

The performance ratio is defined as the numerator divided by the
denominator.

Specifications for incrementing the numerator.

Except as provided for in paragraph (d)(3)(v) of this paragraph (d)(3),
the numerator, when incremented, must be incremented by an integer of
one.  The numerator shall not be incremented more than once per drive
cycle.

The numerator for a specific monitor must be incremented within 10
seconds if and only if the following criteria are satisfied on a single
drive cycle:

Every monitoring condition has been satisfied that is necessary for the
specific monitor to detect a malfunction and store a pending DTC,
including applicable enable criteria, presence or absence of related
DTCs, sufficient length of monitoring time, and diagnostic executive
priority assignments (e.g., diagnostic “A” must execute prior to
diagnostic “B”).  For the purpose of incrementing the numerator,
satisfying all the monitoring conditions necessary for a monitor to
determine that the monitor is not malfunctioning shall not, by itself,
be sufficient to meet this criteria.

For monitors that require multiple stages or events in a single drive
cycle to detect a malfunction, every monitoring condition necessary for
all events to complete must be satisfied.

For monitors that require intrusive operation of components to detect a
malfunction, a manufacturer must request approval of the strategy used
to determine that, had a malfunction been present, the monitor would
have detected the malfunction.  Administrator approval of the request
will be based on the equivalence of the strategy to actual intrusive
operation and the ability of the strategy to determine accurately if
every monitoring condition was satisfied that was necessary for the
intrusive event to occur.

For the secondary air system monitor, the criteria in paragraphs
(d)(3)(ii)(A) through (d)(3)(ii)(C) of this section are satisfied during
normal operation of the secondary air system.  Monitoring during
intrusive operation of the secondary air system later in the same drive
cycle for the sole purpose of monitoring shall not, by itself, be
sufficient to meet these criteria.

For monitors that can generate results in a “gray zone” or
“non-detection zone” (i.e., monitor results that indicate neither a
properly operating system nor a malfunctioning system) or in a
“non-decision zone” (e.g., monitors that increment and decrement
counters until a pass or fail threshold is reached), the numerator, in
general, shall not be incremented when the monitor indicates a result in
the “non-detection zone” or prior to the monitor reaching a complete
decision.  When necessary, the Administrator will consider data and/or
engineering analyses submitted by the manufacturer demonstrating the
expected frequency of results in the “non-detection zone” and the
ability of the monitor to determine accurately, had an actual
malfunction been present, whether or not the monitor would have detected
a malfunction instead of a result in the “non-detection zone.”

For monitors that run or complete their evaluation with the engine off,
the numerator must be incremented either within 10 seconds of the
monitor completing its evaluation in the engine off state, or during the
first 10 seconds of engine start on the subsequent drive cycle.

Manufacturers that use alternative statistical MIL activation protocols
as allowed in paragraph (b)(2)(iii) of this section for any of the
monitors requiring a numerator, are required to increment the
numerator(s) appropriately.  The manufacturer may be required to provide
supporting data and/or engineering analyses demonstrating both the
equivalence of their incrementing approach to the incrementing specified
in this paragraph (d)(3) for monitors using the standard MIL activation
protocol.

Specifications for incrementing the denominator.

The denominator, when incremented, must be incremented by an integer of
one.  The denominator shall not be incremented more than once per drive
cycle.

The denominator for each monitor must be incremented within 10 seconds
if and only if the following criteria are satisfied on a single drive
cycle:

Cumulative time since the start of the drive cycle is greater than or
equal to 600 seconds while at an elevation of less than 8,000 feet
(2,400 meters) above sea level and at an ambient temperature of greater
than or equal to 20 degrees Fahrenheit (-7 C);

Cumulative gasoline engine operation at or above 25 miles per hour or
diesel engine operation at or above 15% calculated load, either of which
occurs for greater than or equal to 300 seconds while at an elevation of
less than 8,000 feet (2,400 meters) above sea level and at an ambient
temperature of greater than or equal to 20 degrees Fahrenheit (-7 C);
and

Continuous vehicle operation at idle (e.g., accelerator pedal released
by driver and vehicle speed less than or equal to one mile per hour) for
greater than or equal to 30 seconds while at an elevation of less than
8,000 feet (2,400 meters) above sea level and at an ambient temperature
of greater than or equal to 20 degrees Fahrenheit (-7 C).

In addition to the requirements of paragraph (d)(4)(ii) of this section,
the evaporative system monitor denominator(s) may be incremented if and
only if:

Cumulative time since the start of the drive cycle is greater than or
equal to 600 seconds while at an ambient temperature of greater than or
equal to 40 degrees Fahrenheit (4 C) but less than or equal to 95
degrees Fahrenheit (35 C); and,

Engine cold start occurs with the engine coolant temperature greater
than or equal to 40 degrees Fahrenheit (4 C) but less than or equal to
95 degrees Fahrenheit (35 C) and less than or equal to 12 degrees
Fahrenheit (7 C) higher than the ambient temperature.

In addition to the requirements of paragraph (d)(4)(ii) of this section,
the denominator(s) for the following monitors may be incremented if and
only if the component or strategy is commanded “on” for a time
greater than or equal to 10 seconds.  For purposes of determining this
commanded “on” time, the OBD system shall not include time during
intrusive operation of any of the components or strategies that occurs
later in the same drive cycle for the sole purpose of monitoring.

Secondary air system (paragraph (h)(5) of this section)

Cold start emission reduction strategy (paragraph (h)(4) of this
section)

Components or systems that operate only at engine start-up (e.g., glow
plugs, intake air heaters) and are subject to monitoring under “other
emission control systems” (paragraph (i)(4) of this section) or
comprehensive component output components (paragraph (i)(3)(iii) of this
section).

In addition to the requirements of paragraph (d)(4)(ii) of this section,
the denominator(s) for the following monitors of output components
(except those operated only at engine start-up and subject to the
requirements of  paragraph  (d)(4)(iv) of this section, may be
incremented if and only if the component is commanded to function (e.g.,
commanded “on”, “opened”, “closed”, “locked”) on two or
more occasions during the drive cycle or for a time greater than or
equal to 10 seconds, whichever occurs first:

Variable valve timing and/or control system (paragraph (g)(10) or (h)(9)
of this section)

 “Other emission control systems” (paragraph (i)(4) of this section)

Comprehensive component output component (paragraph (i)(3) of this
section) (e.g., turbocharger waste-gates, variable length manifold
runners).

For monitors of the following components, the manufacturer may use
alternative or additional criteria for incrementing the denominator to
that set forth in paragraph (d)(4)(ii) of this section.  To do so, the
alternative criteria must be based on equivalence to the criteria of
paragraph (d)(4)(ii) of this section in measuring the frequency of
monitor operation relative to the amount of engine operation:

Engine cooling system input components (paragraph (i)(1) of this
section)

“Other emission control systems” (paragraph (i)(4) of this section)

Comprehensive component input components that require extended
monitoring evaluation (paragraph (i)(3) of this section) (e.g., stuck
fuel level sensor rationality).

For monitors of the following components or other emission controls that
experience infrequent regeneration events, the manufacturer may use
alternative or additional criteria for incrementing the denominator to
that set forth in paragraph (d)(4)(ii) of this section.  To do so, the
alternative criteria must be based on equivalence to the criteria of
paragraph (d)(4)(ii) of this section in measuring the frequency of
monitor operation relative to the amount of engine operation:

Oxidation catalyst (paragraph (g)(5) of this section)

DPF (paragraph (g)(8) of this section).

For hybrids that employ alternative engine start hardware or strategies
(e.g., integrated starter and generators), or alternative fuel vehicles
(e.g., dedicated, bi-fuel, or dual-fuel applications), the manufacturer
may use alternative criteria for incrementing the denominator to that
set forth in paragraph (d)(4)(ii) of this section.  In general, the
Administrator will not approve alternative criteria for those hybrids
that employ engine shut off only at or near idle and/or vehicle stop
conditions.  To use alternative criteria, the alternative criteria must
be based on the equivalence to the criteria of paragraph (d)(4)(ii) of
this section in measuring the amount of vehicle operation relative to
the measure of conventional vehicle operation.

Disablement of numerators and denominators.

Within 10 seconds of detecting a malfunction (i.e., a pending or a
MIL-on DTC has been stored) that disables a monitor for which the
monitoring conditions in paragraph (d) of this section must be met, the
OBD system must stop incrementing the numerator and denominator for any
monitor that may be disabled as a consequence of the detected
malfunction.  Within 10 seconds of the time at which the malfunction is
no longer being detected (e.g., the pending DTC is erased through OBD
system self-clearing or through a scan tool command), incrementing of
all applicable numerators and denominators must resume.

Within 10 seconds of the start of a power take-off unit (e.g., dump bed,
snow plow blade, or aerial bucket, etc.) that disables a monitor for
which the monitoring conditions in paragraph (d) of this section must be
met, the OBD system must stop incrementing the numerator and denominator
for any monitor that may be disabled as a consequence of power take-off
operation.  Within 10 seconds of the time at which the power take-off
operation ends, incrementing of all applicable numerators and
denominators must resume.

Within 10 seconds of detecting a malfunction (i.e., a pending or a
MIL-on DTC has been stored) of any component used to determine if the
criteria of paragraphs (d)(4)(ii) and (d)(4)(iii) of this section are
satisfied, the OBD system must stop incrementing all applicable
numerators and denominators.  Within 10 seconds of the time at which the
malfunction is no longer being detected (e.g., the pending DTC is erased
through OBD system self-clearing or through a scan tool command),
incrementing of all applicable numerators and denominators must resume.

(e) Standardized tracking and reporting of in-use monitor performance

Standardized tracking and reporting of in-use monitor performance.

General. For monitors required to track and report in-use monitor
performance according to paragraph (d) of this section, the performance
data must be tracked and reported in accordance with the specifications
in paragraphs (d)(2), (e), and (k)(5) of this section.  The OBD system
must separately report an in-use monitor performance numerator and
denominator for each of the following components:

For diesel engines, NMHC catalyst bank 1, NMHC catalyst bank 2, NOx
catalyst bank 1, NOx catalyst bank 2, exhaust gas sensor bank 1, exhaust
gas sensor bank 2, EGR/VVT system, DPF, boost pressure control system,
and NOx adsorber.  The OBD system must also report a general denominator
and an ignition cycle counter in the standardized format specified in
paragraphs (e)(5), (e)(6), and (k)(5) of this section.

For gasoline engines, catalyst bank 1, catalyst bank 2, exhaust gas
sensor bank 1, exhaust gas sensor bank 2, evaporative leak detection
system, EGR/VVT system, and secondary air system.  The OBD system must
also report a general denominator and an ignition cycle counter in the
standardized format specified in paragraphs (e)(5), (e)(6), and (k)(5)
of this section.

For specific components or systems that have multiple monitors that are
required to be reported under paragraphs (g) and (h) of this section
(e.g., exhaust gas sensor bank 1 may have multiple monitors for sensor
response or other sensor characteristics), the OBD system must
separately track numerators and denominators for each of the specific
monitors and report only the corresponding numerator and denominator for
the specific monitor that has the lowest numerical ratio.  If two or
more specific monitors have identical ratios, the corresponding
numerator and denominator for the specific monitor that has the highest
denominator must be reported for the specific component.

Numerator.

The OBD system must report a separate numerator for each of the
applicable components listed in paragraph (e)(1) of this section.

The numerator(s) must be reported in accordance with the specifications
in paragraph (k)(5)(ii)of this section.

Denominator.

The OBD system must report a separate denominator for each of the
applicable components listed in paragraph (e)(1) of this section.

The denominator(s) must be reported in accordance with the
specifications in paragraph (k)(5)(ii)of this section.

Monitor performance ratio. For purposes of determining which
corresponding numerator and denominator to report as required in
paragraph (e)(1)(iii) of this section, the ratio must be calculated in
accordance with the specifications in paragraph (k)(5)(iii) of this
section.

Ignition cycle counter.

The ignition cycle counter is defined as a counter that indicates the
number of ignition cycles a vehicle has experienced according to the
specifications of paragraph (e)(5)(ii)(B) of this section. The ignition
cycle counter must be reported in accordance with the specifications in
paragraph (k)(5)(ii)of this section.

The ignition cycle counter must be incremented as follows:

The ignition cycle counter, when incremented, must be incremented by an
integer of one.  The ignition cycle counter shall not be incremented
more than once per ignition cycle.

The ignition cycle counter must be incremented within 10 seconds if and
only if the engine exceeds an engine speed of 50 to 150 rpm below the
normal, warmed-up idle speed (as determined in the drive position for
engines paired with an automatic transmission) for at least two seconds
plus or minus one second.

Within 10 seconds of detecting a malfunction (i.e., a pending or a
MIL-on DTC has been stored) of any component used to determine if the
criteria in paragraph (e)(5)(ii)(B) of this section are satisfied (i.e.,
engine speed or time of operation), the OBD system must stop
incrementing the ignition cycle counter. Incrementing of the ignition
cycle counter shall not be stopped for any other condition.  Within 10
seconds of the time at which the malfunction is no longer being detected
(e.g., the pending DTC is erased through OBD system self-clearing or
through a scan tool command), incrementing of the ignition cycle counter
must resume.

General denominator.

The general denominator is defined as a measure of the number of times
an engine has been operated according to the specifications of paragraph
(e)(6)(ii)(B) of this section.  The general denominator must be reported
in accordance with the specifications in paragraph (k)(5)(ii)of this
section.

The general denominator must be incremented as follows:

The general denominator, when incremented, must be incremented by an
integer of one.  The general denominator shall not be incremented more
than once per drive cycle.

The general denominator must be incremented within 10 seconds if and
only if the criteria identified in paragraph (d)(4)(ii) of this section
are satisfied on a single drive cycle.

Within 10 seconds of detecting a malfunction (i.e., a pending or a
MIL-on DTC has been stored) of any component used to determine if the
criteria in paragraph (d)(4)(ii) of this section are satisfied (i.e.,
vehicle speed/load, ambient temperature, elevation, idle operation, or
time of operation), the OBD system must stop incrementing the general
denominator. Incrementing of the general denominator shall not be
stopped for any other condition (e.g., the disablement criteria in
paragraphs (d)(5)(i) and (d)(5)(ii) of this section shall not disable
the general denominator).  Within 10 seconds of the time at which the
malfunction is no longer being detected (e.g., the pending DTC is erased
through OBD system self-clearing or through a scan tool command),
incrementing of the general denominator must resume.

(f) Malfunction criteria determination

Malfunction criteria determination.

In determining the malfunction criteria for the diesel engine monitors
required under paragraphs (g) and (i) of this section that are required
to indicate a malfunction before emissions exceed an emission threshold
based on any applicable standard, the manufacturer must:

Use the emission test cycle and standard (i.e., the transient FTP or the
supplemental emissions test (SET)) determined by the manufacturer to be
more stringent (i.e., to result in higher emissions with the same level
of monitored component malfunction).  The manufacturer must use data
and/or engineering analysis to determine the test cycle and standard
that is more stringent.

Identify in the certification documentation required under paragraph (m)
of this section, the test cycle and standard determined by the
manufacturer to be the most stringent for each applicable monitor.

If the Administrator reasonably believes that a manufacturer has
determined incorrectly the test cycle and standard that is most
stringent, the manufacturer must be able to provide emission data and/or
engineering analysis supporting their choice of test cycle and standard.

On engines equipped with emission controls that experience infrequent
regeneration events, a manufacturer must adjust the emission test
results that are used to determine the malfunction criteria for monitors
that are required to indicate a malfunction before emissions exceed a
certain emission threshold.  For each such monitor, the manufacturer
must adjust the emission result as done in accordance with the
provisions of section 86.004-28(i) with the component for which the
malfunction criteria are being established having been deteriorated to
the malfunction threshold.  The adjusted emission value must be used for
purposes of determining whether or not the applicable emission threshold
is exceeded.

For purposes of this paragraph (f)(2) of this section, regeneration
means an event, by design, during which emissions levels change while
the emission control performance is being restored.

For purposes of this paragraph (f)(2) of this section, infrequent means
having an expected frequency of less than once per transient FTP cycle.

For gasoline engines, rather than meeting the malfunction criteria
specified under paragraphs (h) and (i) of this section, the manufacturer
may request approval to use an OBD system certified to the requirements
of §86.010-17.  To do so, the manufacturer must demonstrate use of good
engineering judgment in determining equivalent malfunction detection
criteria to those required in this section.

(g) Monitoring requirements for diesel-fueled/CI engines

OBD monitoring requirements for diesel-fueled/compression-ignition
engines. The following table shows the thresholds at which point certain
components or systems, as specified in this paragraph (g), are
considered malfunctioning.

Table   SEQ Table \* ARABIC  1 .  OBD Emissions Thresholds for
Diesel-Fueled/Compression-Ignition Engines meant for Placement in
Applications Greater than 14,000 Pounds GVWR (g/bhp-hr)

Component	§86.010-18 reference	NMHC	CO	NOx	PM

NMHC catalyst system	(g)(5)	2.5x	--	--	--

NOx aftertreatment system	(g)(6)

(g)(7)	--	--	+0.3	--

Diesel particulate filter (DPF) system	(g)(8)	2.5x	--	--	0.05/+0.04

Air-fuel ratio sensors upstream of aftertreatment devices	(g)(9)	2.5x
2.5x	+0.3	0.03/+0.02

Air-fuel ratio sensors downstream of aftertreatment devices	(g)(9)	2.5x
--	+0.3	0.05/+0.04

NOx sensors	(g)(9)	--	--	+0.3	0.05/+0.04

“Other monitors” with emissions thresholds	(g)(1)

(g)(3)

(g)(4)

(g)(10)	2.5x	2.5x	+0.3	0.03/+0.02

Notes: FEL=Family Emissions Limit; 2.5x std means a multiple of 2.5
times the applicable emissions standard; +0.3 means the standard or FEL
plus 0.3; 0.05/+0.04 means an absolute level of 0.05 or an additive
level of the standard or FEL plus 0.04, whilchever level is higher;
these emissions thresholds apply to the monitoring requirements of
paragraph (g) of this section 86.010-18.

(g)(1) Fuel system

Fuel system monitoring.

General. The OBD system must monitor the fuel delivery system to verify
that it is functioning properly.  The individual electronic components
(e.g., actuators, valves, sensors, pumps) that are used in the fuel
system and are not specifically addressed in this paragraph (g)(1) must
be monitored in accordance with the  requirements of paragraph (i)(3)of
this section.

Fuel system malfunction criteria.

Fuel system pressure control. The OBD system must monitor the fuel
system’s ability to control to the desired fuel pressure. This
monitoring must be done continuously unless new hardware has to be
added, in which case the monitoring must be done at least once per drive
cycle.  The OBD system must detect a malfunction of the fuel system’s
pressure control system when the pressure control system is unable to
maintain an engine’s emissions at or below the emissions thresholds
for “other monitors” as shown in Table 1 of this paragraph (g).  For
engines in which no failure or deterioration of the fuel system pressure
control could result in an engine’s emissions exceeding the applicable
emissions thresholds, the OBD system must detect a malfunction when the
system has reached its control limits such that the commanded fuel
system pressure cannot be delivered.

Fuel system injection quantity. The OBD system must detect a malfunction
of the fuel injection system when the system is unable to deliver the
commanded quantity of fuel necessary to maintain an engine’s emissions
at or below the emissions thresholds for “other monitors” as shown
in Table 1 of this paragraph (g).  For engines in which no failure or
deterioration of the fuel injection quantity could result in an
engine’s emissions exceeding the applicable emissions thresholds, the
OBD system must detect a malfunction when the system has reached its
control limits such that the commanded fuel quantity cannot be
delivered.

Fuel system injection timing. The OBD system must detect a malfunction
of the fuel injection system when the system is unable to deliver fuel
at the proper crank angle/timing (e.g., injection timing too advanced or
too retarded) necessary to maintain an engine’s emissions at or below
the emissions thresholds for “other monitors” as shown in Table 1 of
this paragraph (g).  For engines in which no failure or deterioration of
the fuel injection timing could result in an engine’s emissions
exceeding the applicable emissions thresholds, the OBD system must
detect a malfunction when the system has reached its control limits such
that the commanded fuel injection timing cannot be achieved.

Fuel system feedback control. See paragraph (i)(6)of this section.

Fuel system monitoring conditions.

The OBD system must monitor continuously for malfunctions identified in
paragraphs (g)(1)(ii)(A) and (g)(1)(ii)(D) of this section.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraphs (g)(1)(ii)(B) and (g)(1)(ii)(C) in accordance
with paragraphs (c) and  (d) of this section.

Fuel system MIL activation and DTC storage. The MIL must activate and
DTCs must be stored according to the provisions of paragraph (b) of this
section.

(g)(2) Engine misfire

 Engine misfire monitoring.

General. The OBD system must monitor the engine for misfire causing
excess emissions.

Engine misfire malfunction criteria. The OBD system must be capable of
detecting misfire occurring in one or more cylinders.  To the extent
possible without adding hardware for this specific purpose, the OBD
system must also identify the specific misfiring cylinder. If more than
one cylinder is misfiring continuously, a separate DTC must be stored
indicating that multiple cylinders are misfiring.  When identifying
multiple cylinder misfire, the OBD system is not required to identify
individually through separate DTCs each of the continuously misfiring
cylinders.

Engine misfire monitoring conditions.

The OBD system must monitor for engine misfire during engine idle
conditions at least once per drive cycle in which the monitoring
conditions for misfire are met.  The manufacturer must be able to
demonstrate via engineering analysis and/or data that the self-defined
monitoring conditions:  are technically necessary to ensure robust
detection of malfunctions (e.g., avoid false passes and false detection
of malfunctions); require no more than 1000 cumulative engine
revolutions; and, do not require any single continuous idle operation of
more than 15 seconds to make a determination that a malfunction is
present (e.g., a decision can be made with data gathered during several
idle operations of 15 seconds or less); or, satisfy the requirements of
paragraph (c) of this section with alternative engine operating
conditions.

Manufacturers may employ alternative monitoring conditions (e.g.,
off-idle) provided the manufacturer is able to demonstrate that the
alternative monitoring ensure equivalent robust detection of
malfunctions and equivalent timeliness in detection of malfunctions.

Engine misfire MIL activation and DTC storage. The MIL must activate and
DTCs must be stored according to the provisions of paragraph (b) of this
section.

(g)(3) EGR system

 EGR system monitoring.

General. The OBD system must monitor the EGR system on engines so
equipped for low flow rate, high flow rate, and slow response
malfunctions.  For engines equipped with EGR coolers (e.g., heat
exchangers), the OBD system must monitor the cooler for insufficient
cooling malfunctions.  The individual electronic components (e.g.,
actuators, valves, sensors) that are used in the EGR system must be
monitored in accordance with the comprehensive component requirements in
paragraph (i)(3) of this section.

EGR system malfunction criteria.

EGR low flow.  The OBD system must detect a malfunction of the EGR
system prior to a decrease from the manufacturer’s specified EGR flow
rate that would cause an engine’s emissions to exceed the emissions
thresholds for “other monitors” as shown in Table 1 of this
paragraph (g). For engines in which no failure or deterioration of the
EGR system that causes a decrease in flow could result in an engine’s
emissions exceeding the applicable emissions thresholds, the OBD system
must detect a malfunction when the system has reached its control limits
such that it cannot increase EGR flow to achieve the commanded flow
rate.

EGR high flow. The OBD system must detect a malfunction of the EGR
system, including a leaking EGR valve (i.e., exhaust gas flowing through
the valve when the valve is commanded closed) prior to an increase from
the manufacturer’s specified EGR flow rate that would cause an
engine’s emissions to exceed the emissions thresholds for “other
monitors” as shown in Table 1 of this paragraph (g).  For engines in
which no failure or deterioration of the EGR system that causes an
increase in flow could result in an engine’s emissions exceeding the
applicable emissions thresholds, the OBD system must detect a
malfunction when the system has reached its control limits such that it
cannot reduce EGR flow to achieve the commanded flow rate.

EGR slow response. The OBD system must detect a malfunction of the EGR
system prior to any failure or deterioration in the capability of the
EGR system to achieve the commanded flow rate within a
manufacturer-specified time that would cause an engine’s emissions to
exceed the emissions thresholds for “other monitors” as shown in
Table 1 of this paragraph (g).  The OBD system must monitor both the
capability of the EGR system to respond to a commanded increase in flow
and the capability of the EGR system to respond to a commanded decrease
in flow.

EGR system feedback control. See paragraph (i)(6)of this section.

EGR cooler performance. The OBD system must detect a malfunction of the
EGR cooler prior to a reduction from the manufacturer’s specified
cooling performance that would cause an engine’s emissions to exceed
the emissions thresholds for “other monitors” as shown in Table 1 of
this paragraph (g).  For engines in which no failure or deterioration of
the EGR cooler could result in an engine’s emissions exceeding the
applicable emissions thresholds, the OBD system must detect a
malfunction when the system has no detectable amount of EGR cooling.

EGR system monitoring conditions.

The OBD system must monitor continuously for malfunctions identified in
paragraphs (g)(3)(ii)(A), (g)(3)(ii)(B), and (g)(3)(ii)(D) of this
section.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraph (g)(3)(ii)(C) in accordance with paragraphs (c)
and  (d) of this section, with the exception that monitoring must occur
every time the monitoring conditions are met during the drive cycle
rather than once per drive cycle as required in paragraph (c)(2) of this
section.  For purposes of tracking and reporting as required in
paragraph (d)(1) of this section, all monitors used to detect
malfunctions identified in paragraph (g)(3)(ii)(C) of this section must
be tracked separately but reported as a single set of values as
specified in paragraph (e)(1)(iii) of this section.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraph (g)(3)(ii)(E) of this section in accordance with
paragraphs (c) and  (d) of this section. For purposes of tracking and
reporting as required in paragraph (d)(1) of this section, all monitors
used to detect malfunctions identified in paragraph (g)(3)(ii)(E) of
this section must be tracked separately but reported as a single set of
values as specified in paragraph (e)(1)(iii) of this section.

The manufacturer may request Administrator approval to disable
temporarily the EGR system monitor(s) under specific conditions (e.g.,
when freezing may affect performance of the system) provided the
manufacturer is able to demonstrate via data or engineering analysis
that a reliable monitor cannot be run when these conditions exist.

EGR system MIL activation and DTC storage. The MIL must activate and
DTCs must be stored according to the provisions of paragraph (b) of this
section.

(g)(4) Turbo boost control system

Turbo boost control system monitoring.

General. The OBD system must monitor the boost pressure control system
(e.g., turbocharger) on engines so equipped for under and over boost
malfunctions.  For engines equipped with variable geometry turbochargers
(VGT), the OBD system must monitor the VGT system for slow response
malfunctions.  For engines equipped with charge air cooler systems, the
OBD system must monitor the charge air cooler system for cooling system
performance malfunctions.  The individual electronic components (e.g.,
actuators, valves, sensors) that are used in the boost pressure control
system must be monitored in accordance with the comprehensive component
requirements in paragraph (i)(3) of this section.

Turbo boost control system malfunction criteria.

Turbo underboost. The OBD system must detect a malfunction of the boost
pressure control system prior to a decrease from the manufacturer’s
commanded boost pressure that would cause an engine’s emissions to
exceed the emissions thresholds for “other monitors” as shown in
Table 1 of this paragraph (g).  For engines in which no failure or
deterioration of the boost pressure control system that causes a
decrease in boost could result in an engine’s emissions exceeding the
applicable emissions thresholds, the OBD system must detect a
malfunction when the system has reached its control limits such that it
cannot increase boost to achieve the commanded boost pressure.

Turbo overboost. The OBD system must detect a malfunction of the boost
pressure control system prior to an increase from the manufacturer’s
commanded boost pressure that would cause an engine’s emissions to
exceed the emissions thresholds for “other monitors” as shown in
Table 1 of this paragraph (g).  For engines in which no failure or
deterioration of the boost pressure control system that causes an
increase in boost could result in an engine’s emissions exceeding the
applicable emissions thresholds, the OBD system must detect a
malfunction when the system has reached its control limits such that it
cannot decrease boost to achieve the commanded boost pressure.

VGT slow response. The OBD system must detect a malfunction prior to any
failure or deterioration in the capability of the VGT system to achieve
the commanded turbocharger geometry within a manufacturer-specified time
that would cause an engine’s emissions to exceed the emissions
thresholds for “other monitors” as shown in Table 1 of this
paragraph (g).  For engines in which no failure or deterioration of the
VGT system response could result in an engine’s emissions exceeding
the applicable emissions thresholds, the OBD system must detect a
malfunction of the VGT system when proper functional response of the
system to computer commands does not occur.

Turbo boost feedback control. See paragraph (i)(6)of this section.

Charge air undercooling. The OBD system must detect a malfunction of the
charge air cooling system prior to a decrease from the manufacturer’s
specified cooling rate that would cause an engine’s emissions to
exceed the emissions thresholds for “other monitors” as shown in
Table 1 of this paragraph (g).  For engines in which no failure or
deterioration of the charge air cooling system that causes a decrease in
cooling performance could result in an engine’s emissions exceeding
the applicable emissions thresholds, the OBD system must detect a
malfunction when the system has no detectable amount of charge air
cooling.

Turbo boost monitoring conditions.

The OBD system must monitor continuously for malfunctions identified in
paragraphs (g)(4)(ii)(A), (g)(4)(ii)(B), and (g)(4)(ii)(D) of this
section.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraph (g)(4)(ii)(C) of this section in accordance with
paragraphs (c) and  (d) of this section, with the exception that
monitoring must occur every time the monitoring conditions are met
during the drive cycle rather than once per drive cycle as required in
paragraph (c)(2) of this section.  For purposes of tracking and
reporting as required in paragraph (d)(1) of this section, all monitors
used to detect malfunctions identified in paragraph (g)(4)(ii)(C) of
this section must be tracked separately but reported as a single set of
values as specified in paragraph (e)(1)(iii) of this section.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraph (g)(4)(ii)(E) of this section in accordance with
paragraphs (c) and  (d) of this section. For purposes of tracking and
reporting as required in paragraph (d)(1) of this section, all monitors
used to detect malfunctions identified in paragraph (g)(4)(ii)(E) of
this section must be tracked separately but reported as a single set of
values as specified in paragraph (e)(1)(iii) of this section.

Turbo boost system MIL activation and DTC storage. The MIL must activate
and DTCs must be stored according to the provisions of paragraph (b) of
this section.

(g)(5) NMHC catalyst

 NMHC converting catalyst monitoring.

General. The OBD system must monitor the NMHC converting catalyst(s) for
proper NMHC conversion capability.  For engines equipped with catalyzed
diesel particulate filter(s) (DPF) that convert NMHC emissions, the
catalyst function of the DPF must be monitored in accordance with the
DPF requirements of paragraph (g)(8) of this section. For purposes of
this paragraph (g)(5), each catalyst that converts NMHC must be
monitored either individually or in combination with others.

NMHC converting catalyst malfunction criteria.

NMHC converting catalyst conversion efficiency. The OBD system must
detect a catalyst malfunction when the catalyst conversion capability
decreases to the point that NMHC emissions exceed the emissions
thresholds for the NMHC catalyst system as shown in Table 1 of this
paragraph (g). If no failure or deterioration of the catalyst NMHC
conversion capability could result in an engine’s NMHC emissions
exceeding the applicable emissions thresholds, the OBD system must
detect a malfunction when the catalyst has no detectable amount of NMHC
conversion capability.

NMHC converting catalyst aftertreatment assistance functions. For
catalysts used to generate an exotherm to assist DPF regeneration, the
OBD system must detect a malfunction when the catalyst is unable to
generate a sufficient exotherm to achieve DPF regeneration. For
catalysts used to generate a feedgas constituency to assist selective
catalytic reduction (SCR) systems (e.g., to increase NO2 concentration
upstream of an SCR system), the OBD system must detect a malfunction
when the catalyst is unable to generate the necessary feedgas
constituents for proper SCR system operation. For catalysts located
downstream of a DPF and used to convert NMHC emissions during DPF
regeneration, the OBD system must detect a malfunction when the catalyst
has no detectable amount of NMHC conversion capability.

NMHC converting catalyst monitoring conditions. The manufacturer must
define the monitoring conditions for malfunctions identified in
paragraphs (g)(5)(ii)(A) and (g)(5)(ii)(B) of this section in accordance
with paragraphs (c) and  (d) of this section.  For purposes of tracking
and reporting as required in paragraph (d)(1) of this section, all
monitors used to detect malfunctions identified in paragraphs
(g)(5)(ii)(A) and (g)(5)(ii)(B) of this section must be tracked
separately but reported as a single set of values as specified in
paragraph (e)(1)(iii) of this section.

NMHC converting catalyst MIL activation and DTC storage. The MIL must
activate and DTCs must be stored according to the provisions of
paragraph (b) of this section. The monitoring method for the NMHC
converting catalyst(s) must be capable of detecting all instances,
except diagnostic self-clearing, when a catalyst DTC has been erased but
the catalyst has not been replaced (e.g., catalyst over-temperature
histogram approaches are not acceptable).

(g)(6) SCR & lean NOx catalyst

 Selective catalytic reduction (SCR) and lean NOx catalyst monitoring.

General. The OBD system must monitor the SCR and/or the lean NOx
converting catalyst(s) for proper conversion capability.  For engines
equipped with SCR systems or other catalyst systems that use an
active/intrusive reductant injection (e.g., active lean NOx catalysts
that use diesel fuel post-injection or in-exhaust injection), the OBD
system must monitor the active/intrusive reductant injection system for
proper performance.  The individual electronic components (e.g.,
actuators, valves, sensors, heaters, pumps) in the active/intrusive
reductant injection system must be monitored in accordance with the
comprehensive component requirements in paragraph (i)(3) of this
section. For purposes of this paragraph (g)(6), each catalyst that
converts NOx must be monitored either individually or in combination
with others.

SCR and lean NOx catalyst malfunction criteria.

SCR and lean NOx catalyst conversion efficiency. The OBD system must
detect a catalyst malfunction when the catalyst conversion capability
decreases to the point that would cause an engine’s emissions to
exceed the emissions thresholds for NOx aftertreatment systems as shown
in Table 1 of this paragraph (g). If no failure or deterioration of the
catalyst NOx conversion capability could result in an engine’s
emissions exceeding any of the applicable emissions thresholds, the OBD
system must detect a malfunction when the catalyst has no detectable
amount of NOx conversion capability.

SCR and lean NOx catalyst active/intrusive reductant delivery
performance. The OBD system must detect a malfunction prior to any
failure or deterioration of the system to properly regulate reductant
delivery (e.g., urea injection, separate injector fuel injection, post
injection of fuel, air assisted injection/mixing) that would cause an
engine’s emissions to exceed any of the applicable emissions
thresholds for NOx aftertreatment systems as shown in Table 1 of this
paragraph (g).  If no failure or deterioration of the reductant delivery
system could result in an engine’s emissions exceeding any of the
applicable thresholds, the OBD system must detect a malfunction when the
system has reached its control limits such that it is no longer able to
deliver the desired quantity of reductant.

SCR and lean NOx catalyst active/intrusive reductant quantity. If the
SCR or lean NOx catalyst system uses a reductant other than the fuel
used for the engine, or uses a reservoir/tank for the reductant that is
separate from the fuel tank used for the engine, the OBD system must
detect a malfunction when there is no longer sufficient reductant
available (e.g., the reductant tank is empty).

SCR and lean NOx catalyst active/intrusive reductant quality. If the SCR
or lean NOx catalyst system uses a reservoir/tank for the reductant that
is separate from the fuel tank used for the engine, the OBD system must
detect a malfunction when an improper reductant is used in the reductant
reservoir/tank (e.g., the reductant tank is filled with something other
than the reductant).

SCR and lean NOx catalyst active/intrusive reductant feedback control.
See paragraph (i)(6)of this section.

SCR and lean NOx catalyst monitoring conditions.

The manufacturers must define the monitoring conditions for malfunctions
identified in paragraphs (g)(6)(ii)(A) and (g)(6)(ii)(D)of this section
in accordance with paragraphs (c) and  (d) of this section.  For
purposes of tracking and reporting as required in paragraph (d)(1) of
this section, all monitors used to detect malfunctions identified in
paragraph (g)(6)(ii)(A) of this section must be tracked separately but
reported as a single set of values as specified in paragraph (e)(1)(iii)
of this section.

The OBD system must monitor continuously for malfunctions identified in
paragraphs (g)(6)(ii)(B), (g)(6)(ii)(C), and (g)(6)(ii)(E) of this
section.

SCR and lean NOx catalyst MIL activation and DTC storage.

For malfunctions identified in paragraph (g)(6)(ii)(A) of this section,
the MIL must activate and DTCs must be stored according to the
provisions of paragraph (b) of this section.

For malfunctions identified in paragraphs (g)(6)(ii)(B), (g)(6)(ii)(C),
and (g)(6)(ii)(D) of this section, the manufacturer may delay activating
the MIL if the vehicle is equipped with an alternative indicator for
notifying the vehicle operator of the malfunction.  The alternative
indicator must be of sufficient illumination and be located such that it
is readily visible to the vehicle operator under all lighting
conditions. If the vehicle is not equipped with such an alternative
indicator and the OBD MIL activates, the MIL may be immediately
deactivated and the corresponding DTC(s) erased once the OBD system has
verified that the reductant tank has been refilled properly and the MIL
has not been activated for any other malfunction. The Administrator may
approve other strategies that provide equivalent assurance that a
vehicle operator would be promptly notified and that corrective action
would be taken.

The monitoring method for the SCR and lean NOx catalyst(s) must be
capable of detecting all instances, except diagnostic self-clearing,
when a catalyst DTC(s) has been erased but the catalyst has not been
replaced (e.g., catalyst over-temperature histogram approaches are not
acceptable).

(g)(7) NOx adsorber system

 NOx adsorber system monitoring.

General. The OBD system must monitor the NOx adsorber on engines
so-equipped for proper performance.  For engines equipped with
active/intrusive injection (e.g., in-exhaust fuel and/or air injection)
to achieve desorption of the NOx adsorber, the OBD system must monitor
the active/intrusive injection system for proper performance.  The
individual electronic components (e.g., injectors, valves, sensors) that
are used in the active/intrusive injection system must be monitored in
accordance with the comprehensive component requirements in paragraph
(i)(3) of this section.

NOx adsorber system malfunction criteria.

NOx adsorber system capability. The OBD system must detect a NOx
adsorber malfunction when its capability (i.e., its combined adsorption
and conversion capability) decreases to the point that would cause an
engine’s NOx emissions to exceed the emissions thresholds for NOx
aftertreatment systems as shown in Table 1 of this paragraph (g).  If no
failure or deterioration of the NOx adsorber capability could result in
an engine’s NOx emissions exceeding the applicable emissions
thresholds, the OBD system must detect a malfunction when the system has
no detectable amount of NOx adsorber capability.

NOx adsorber system active/intrusive reductant delivery performance. For
NOx adsorber systems that use active/intrusive injection (e.g.,
in-cylinder post fuel injection, in-exhaust air-assisted fuel injection)
to achieve desorption of the NOx adsorber, the OBD system must detect a
malfunction if any failure or deterioration of the injection system’s
ability to properly regulate injection causes the system to be unable to
achieve desorption of the NOx adsorber.

NOx adsorber system feedback control. Malfunction criteria for the NOx
adsorber and the NOx adsorber active/instrusive reductant delivery
system are contained in paragraph (i)(6)of this section.

NOx adsorber system monitoring conditions.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraph (g)(7)(ii)(A) of this section in accordance with
paragraphs (c) and  (d) of this section.  For purposes of tracking and
reporting as required in paragraph (d)(1) of this section, all monitors
used to detect malfunctions identified in paragraph (g)(7)(ii)(A) of
this section must be tracked separately but reported as a single set of
values as specified in paragraph (e)(1)(iii) of this section.

The OBD system must monitor continuously for malfunctions identified in
paragraphs (g)(7)(ii)(B) and (g)(7)(ii)(C) of this section.

NOx adsorber system MIL activation and DTC storage. The MIL must
activate and DTCs must be stored according to the provisions of
paragraph (b) of this section.

(g)(8) DPF system

 Diesel particulate filter (DPF) system monitoring.

General. The OBD system must monitor the DPF on engines so-equipped for
proper performance.  For engines equipped with active regeneration
systems that use an active/intrusive injection (e.g., in-exhaust fuel
injection, in-exhaust fuel/air burner), the OBD system must monitor the
active/intrusive injection system for proper performance.  The
individual electronic components (e.g., injectors, valves, sensors) that
are used in the active/intrusive injection system must be monitored in
accordance with the comprehensive component requirements in paragraph
(i)(3) of this section.

DPF system malfunction criteria.

DPF filtering performance. The OBD system must detect a malfunction
prior to a decrease in the PM filtering capability of the DPF (e.g.,
cracking, melting, etc.) that would cause an engine’s PM emissions to
exceed the emissions thresholds for DPF systems as shown in Table 1 of
this paragraph (g).  If no failure or deterioration of the PM filtering
performance could result in an engine’s PM emissions exceeding the
applicable emissions thresholds, the OBD system must detect a
malfunction when no detectable amount of PM filtering occurs.

DPF regeneration frequency. The OBD system must detect a malfunction
when the DPF regeneration frequency increases from (i.e., occurs more
often than) the manufacturer’s specified regeneration frequency to a
level such that it would cause an engine’s NMHC emissions to exceed
the emissions threshold for DPF systems as shown in Table 1 of this
paragraph (g).  If no such regeneration frequency exists that could
cause NMHC emissions to exceed the applicable emission threshold, the
OBD system must detect a malfunction when the DPF regeneration frequency
exceeds the manufacturer’s specified design limits for allowable
regeneration frequency.

DPF incomplete regeneration. The OBD system must detect a regeneration
malfunction when the DPF does not properly regenerate under
manufacturer-defined conditions where regeneration is designed to occur.

DPF NMHC conversion. For any DPF that serves to convert NMHC emissions,
the OBD system must detect a malfunction when the NMHC conversion
capability decreases to the point that NMHC emissions exceed the
emissions threshold for DPF systems as shown in Table 1 of this
paragraph (g).  If no failure or deterioration of the NMHC conversion
capability could result in NMHC emissions exceeding the applicable
threshold, the OBD system must detect a malfunction when the system has
no detectable amount of NMHC conversion capability.

DPF missing substrate. The OBD system must detect a malfunction if
either the DPF substrate is completely destroyed, removed, or missing,
or if the DPF assembly has been replaced with a muffler or straight
pipe.

DPF system active/intrusive injection. For DPF systems that use
active/intrusive injection (e.g., in-cylinder post fuel injection,
in-exhaust air-assisted fuel injection) to achieve regeneration of the
DPF, the OBD system must detect a malfunction if any failure or
deterioration of the injection system’s ability to properly regulate
injection causes the system to be unable to achieve regeneration of the
DPF.

DPF regeneration feedback control. See paragraph (i)(6) of this section.

DPF monitoring conditions. The manufacturer must define the monitoring
conditions for malfunctions identified in paragraph (g)(8)(ii) of this
section in accordance with paragraphs (c) and  (d) of this section, with
the exception that monitoring must occur every time the monitoring
conditions are met during the drive cycle rather than once per drive
cycle as required in paragraph (c)(2) of this section.  For purposes of
tracking and reporting as required in paragraph (d)(1) of this section,
all monitors used to detect malfunctions identified in paragraph
(g)(8)(ii) of this section must be tracked separately but reported as a
single set of values as specified in paragraph (e)(1)(iii) of this
section.

DPF system MIL activation and DTC storage. The MIL must activate and
DTCs must be stored according to the provisions of paragraph (b) of this
section.

(g)(9) Exhaust gas sensors

 Exhaust gas sensor and sensor heater monitoring.

General. The OBD system must monitor for proper output signal, activity,
response rate, and any other parameter that can affect emissions, all
exhaust gas sensors (e.g., oxygen, air-fuel ratio, NOx) used for
emission control system feedback (e.g., EGR control/feedback, SCR
control/feedback, NOx adsorber control/feedback) and/or as a monitoring
device. For engines equipped with heated exhaust gas sensors, the OBD
system must monitor the heater for proper performance.

Malfunction criteria for air-fuel ratio sensors located upstream of
aftertreatment devices.

Sensor performance. The OBD system must detect a malfunction prior to
any failure or deterioration of the sensor voltage, resistance,
impedance, current, response rate, amplitude, offset, or other
characteristic(s) that would cause an engine’s emissions to exceed the
emissions thresholds for “other monitors” as shown in Table 1 of
this paragraph (g).

Circuit integrity. The OBD system must detect malfunctions of the sensor
related to a lack of circuit continuity or signal out-of-range values.

Feedback function. The OBD system must detect a malfunction of the
sensor if the emission control system (e.g., EGR, SCR, or NOx adsorber)
is unable to use that sensor as a feedback input (e.g., causes limp-home
or open-loop operation).

Monitoring function. To the extent feasible, the OBD system must detect
a malfunction of the sensor when the sensor output voltage, resistance,
impedance, current, amplitude, activity, offset, or other
characteristics are no longer sufficient for use as an OBD system
monitoring device (e.g., for catalyst, EGR, SCR, or NOx adsorber
monitoring).

Malfunction criteria for air-fuel ratio sensors located downstream of
aftertreatment devices.

Sensor performance. The OBD system must detect a malfunction prior to
any failure or deterioration of the sensor voltage, resistance,
impedance, current, response rate, amplitude, offset, or other
characteristic(s) that would cause an engine’s emissions to exceed the
emissions thresholds for air-fuel ratio sensors downstream of
aftertreatment devices as shown in Table 1 of this paragraph (g).

Circuit integrity. The OBD system must detect malfunctions of the sensor
related to a lack of circuit continuity or signal out-of-range values.

Feedback function. The OBD system must detect a malfunction of the
sensor if the emission control system (e.g., EGR, SCR, or NOx adsorber)
is unable to use that sensor as a feedback input (e.g., causes limp-home
or open-loop operation).

Monitoring function. To the extent feasible, the OBD system must detect
a malfunction of the sensor when the sensor output voltage, resistance,
impedance, current, amplitude, activity, offset, or other
characteristics are no longer sufficient for use as an OBD system
monitoring device (e.g., for catalyst, EGR, SCR, or NOx adsorber
monitoring).

Malfunction criteria for NOx sensors.

Sensor performance. The OBD system must detect a malfunction prior to
any failure or deterioration of the sensor voltage, resistance,
impedance, current, response rate, amplitude, offset, or other
characteristic(s) that would cause an engine’s emissions to exceed the
emissions thresholds for NOx sensors as shown in Table 1 of this
paragraph (g).

Circuit integrity. The OBD system must detect malfunctions of the sensor
related to a lack of circuit continuity or signal out-of-range values.

Feedback function. The OBD system must detect a malfunction of the
sensor if the emission control system (e.g., EGR, SCR, or NOx adsorber)
is unable to use that sensor as a feedback input (e.g., causes limp-home
or open-loop operation).

Monitoring function. To the extent feasible, the OBD system must detect
a malfunction of the sensor when the sensor output voltage, resistance,
impedance, current, amplitude, activity, offset, or other
characteristics are no longer sufficient for use as an OBD system
monitoring device (e.g., for catalyst, EGR, SCR, or NOx adsorber
monitoring).

Malfunction criteria for other exhaust gas sensors. For other exhaust
gas sensors, the manufacturer must submit a monitoring plan to the
Administrator for approval.  The plan must include data and/or
engineering evaluations that demonstrate that the monitoring plan is as
reliable and effective as the monitoring required in paragraphs
(g)(9)(ii) through (g)(9)(iv) of this section.

Malfunction criteria for exhaust gas sensor heaters.

The OBD system must detect a malfunction of the heater performance when
the current or voltage drop in the heater circuit is no longer within
the manufacturer’s specified limits for normal operation (i.e., within
the criteria required to be met by the component vendor for heater
circuit performance at high mileage).  The manufacturer may use other
malfunction criteria for heater performance malfunctions. To do so, the
manufacturer must be able to demonstrate via data and/or an engineering
evaluation that the monitor is reliable and robust.

The OBD system must detect malfunctions of the heater circuit including
open or short circuits that conflict with the commanded state of the
heater (e.g., shorted to 12 Volts when commanded to 0 Volts (ground)).

Monitoring conditions for exhaust gas sensors.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraphs (g)(9)(ii)(A), (g)(9)(iii)(A), and
(g)(9)(iv)(A) of this section (i.e., sensor performance) in accordance
with paragraphs (c) and (d) of this section.  For purposes of tracking
and reporting as required in paragraph (d)(1) of this section, all
monitors used to detect malfunctions identified in paragraphs
(g)(9)(ii)(A), (g)(9)(iii)(A), and (g)(9)(iv)(A) of this section must be
tracked separately but reported as a single set of values as specified
in paragraph (e)(1)(iii) of this section.

The manufacturer must define the monitoring conditions for malfunctions
identified in paragraphs (g)(9)(ii)(D), (g)(9)(iii)(D), and
(g)(9)(iv)(D) of this section (i.e., monitoring function) in accordance
with paragraphs (c) and (d) of this section with the exception that
monitoring must occur every time the monitoring conditions are met
during the drive cycle rather than once per drive cycle as required in
paragraph (c)(2) of this section.

Except as provided for in paragraph (g)(9)(vii)(D)of this paragraph
(g)(9), the OBD system must monitor continuously for malfunctions
identified in paragraphs (g)(9)(ii)(B), (g)(9)(ii)(C), (g)(9)(iii)(B),
(g)(9)(iii)(C), (g)(9)(iv)(B), and (g)(9)(iv)(C) (i.e., circuit
integrity and feedback function).

A manufacturer may request approval to disable continuous exhaust gas
sensor monitoring when an exhaust gas sensor malfunction cannot be
distinguished from other effects (e.g., disable monitoring for
out-of-range on the low side during fuel cut conditions).  To do so, the
manufacturer must demonstrate via data and/or engineering analyses that
a properly functioning sensor cannot be distinguished from a
malfunctioning sensor and that the disablement interval is limited only
to that necessary for avoiding false malfunction detection.

Monitoring conditions for exhaust gas sensor heaters.

The manufacturer must define monitoring conditions for malfunctions
identified in paragraph (g)(9)(vi)(A) of this section (i.e., sensor
heater performance) in accordance with paragraphs (c) and (d) of this
section.

The OBD system must monitor continuously for malfunctions identified in
paragraph (g)(9)(vi)(B) of this section (i.e., circuit malfunctions).

Exhaust gas sensor and sensor heater MIL activation and DTC storage. The
MIL must activate and DTCs must be stored according to the provisions of
paragraph (b) of this section.

(g)(10) VVT system

Variable Valve Timing (VVT) system monitoring.

General. The OBD system must monitor the VVT system on engines so
equipped for target error and slow response malfunctions.  The
individual electronic components (e.g., actuators, valves, sensors) that
are used in the VVT system must be monitored in accordance with the
comprehensive components requirements in paragraph (i)(3) of this
section.

VVT system malfunction criteria.

VVT system target error. The OBD system must detect a malfunction prior
to any failure or deterioration in the capability of the VVT system to
achieve the commanded valve timing and/or control within a crank angle
and/or lift tolerance that would cause an engine’s emissions to exceed
the emission thresholds for “other monitors” as shown in Table 1 of
this paragraph (g).

VVT slow response. The OBD system must detect a malfunction prior to any
failure or deterioration in the capability of the VVT system to achieve
the commanded valve timing and/or control within a
manufacturer-specified time that would cause an engine’s emissions to
exceed the emission thresholds for “other monitors” as shown in
Table 1 of this paragraph (g).

For engines in which no failure or deterioration of the VVT system could
result in an engine’s emissions exceeding the applicable emissions
thresholds of paragraphs (g)(10)(ii)(A) and (g)(10)(ii)(B) of this
section, the OBD system must detect a malfunction of the VVT system when
proper functional response of the system to computer commands does not
occur.

VVT system monitoring conditions. Manufacturers must define the
monitoring conditions for VVT system malfunctions identified in
paragraph (g)(10)(ii) of this section in accordance with paragraphs (c)
and (d) of this section, with the exception that monitoring must occur
every time the monitoring conditions are met during the drive cycle
rather than once per drive cycle as required in paragraph (c)(2) of this
section.  For purposes of tracking and reporting as required in
paragraph (d)(1) of this section, all monitors used to detect
malfunctions identified in paragraph (g)(10)(ii) of this section must be
tracked separately but reported as a single set of values as specified
in paragraph (e)(1)(iii) of this section.

VVT MIL activation and DTC storage. The MIL must activate and DTCs must
be stored according to the provisions of paragraph (b) of this section.

(h) Monitoring requirements for gasoline-fueled/SI engines

OBD monitoring requirements for gasoline-fueled/spark-ignition engines.
The following table shows the thresholds at which point certain
components or systems, as specified in this paragraph (h), are
considered malfunctioning.

Table   SEQ Table \* ARABIC  2 .  OBD Emissions Thresholds for
Gasoline-Fueled/Spark-Ignition Engines meant for Placement in
Applications Greater than 14,000 Pounds GVWR (g/bhp-hr)

Component	NOx	NMHC	CO	§86.010-18 reference

Catalyst system	1.75x std	1.75x std	--	(h)(6)

Evaporative emissions control system	--	0.150 inch leak	--	(h)(7)

“Other monitors” with emissions thresholds	1.5x std	1.5x std	1.5x
std	(h)(1), (h)(2)

(h)(3), (h)(4)

(h)(5), (h)(8)

(h)(9)

Notes: 1.75x std means a multiple of 1.75 times the applicable emissions
standard; these emissions thresholds apply to the monitoring
requirements of paragraph (h) of this section 86.010-18; The evaporative
emissions control system threshold is not, technically, an emissions
threshold but rather a leak size that must be detected; nonetheless, for
ease we refer to this as the threshold.

(h)(1) Fuel system

Fuel system monitoring.

General. The OBD system must monitor the fuel delivery system to
determine its ability to provide compliance with emission standards.

Fuel system malfunction criteria.

The OBD system must detect a malfunction of the fuel delivery system
(including feedback control based on a secondary oxygen sensor) when the
fuel delivery system is unable to maintain an engine’s emissions at or
below the emissions thresholds for “other monitors” as shown in
Table 2 of this paragraph (h).

Except as provided for in paragraph (h)(1)(ii)(C) of this section, if
the engine is equipped with adaptive feedback control, the OBD system
must detect a malfunction when the adaptive feedback control has used up
all of the adjustment allowed by the manufacturer.

If the engine is equipped with feedback control that is based on a
secondary oxygen (or equivalent) sensor, the OBD system is not required
to detect a malfunction of the fuel system solely when the feedback
control based on a secondary oxygen sensor has used up all of the
adjustment allowed by the manufacturer.  However, if a failure or
deterioration results in engine emissions that exceed the emissions
thresholds for “other monitors” as shown in Table 2 of this
paragraph (h), the OBD system is required to detect a malfunction.

The OBD system must detect a malfunction whenever the fuel control
system fails to enter closed loop operation following engine start
within a manufacturer specified time interval.  The specified time
interval must be supported by data and/or engineering analyses submitted
by the manufacturer.

The manufacturer may adjust the malfunction criteria and/or monitoring
conditions to compensate for changes in altitude, for temporary
introduction of large amounts of purge vapor, or for other similar
identifiable operating conditions when such conditions occur.

Fuel system monitoring conditions. The fuel system must be monitored
continuously for the presence of a malfunction.

Fuel system MIL activation and DTC storage.

A pending DTC must be stored immediately upon the fuel system exceeding
the malfunction criteria established in paragraph (h)(1)(ii) of this
section.

Except as provided for in paragraph (h)(1)(iv)(C) of this section, if a
pending DTC is stored, the OBD system must activate the MIL immediately
and store a MIL-on DTC if a malfunction is again detected during either
the drive cycle immediately following storage of the pending DTC
regardless of the conditions encountered during that drive cycle, or on
the next drive cycle in which similar conditions are encountered to
those that occurred when the pending DTC was stored. Similar conditions
means engine conditions having an engine speed within 375 rpm, load
conditions within 20 percent, and the same warm up status (i.e., cold or
hot) as the engine conditions stored pursuant to paragraph (h)(1)(iv)(E)
of this section. Other definitions of similar conditions may be used but
must result in comparable timeliness and reliability in detecting
similar engine operation.

The pending DTC may be erased at the end of the next drive cycle in
which similar conditions have been encountered without having again
exceeded the specified fuel system malfunction criteria.  The pending
DTC may also be erased if similar conditions are not encountered during
the 80 drive cycles immediately following detection of the potential
malfunction for which the pending DTC was stored.

Storage of freeze frame conditions. The OBD system must store and erase
freeze frame conditions either in conjunction with storing and erasing a
pending DTC or in conjunction with storing and erasing a MIL-on DTC.
Freeze frame information associated with a fuel system malfunction shall
be stored in preference to freeze frame information required elsewhere
in paragraphs (h) or (i) of this section.

Storage of fuel system conditions for determining similar conditions of
operation.  The OBD must store the engine speed, load, and warm-up
status present at the time it first detects a potential malfunction
meeting the criteria of paragraph (h)(1)(ii) of this section and stores
a pending DTC.

Deactivating the MIL. The MIL may be extinguished after three sequential
driving cycles in which similar conditions have been encountered without
detecting a malfunction of the fuel system.

(h)(2) Engine misfire

Engine misfire monitoring.

General.

The OBD system must monitor the engine for misfire causing catalyst
damage and misfire causing excess emissions.

The OBD system must identify the specific cylinder that is misfiring.
The manufacturer may store a general misfire DTC instead of a cylinder
specific DTC under certain operating conditions.  To do so, the
manufacturer must submit data and/or engineering analyses that
demonstrate that the misfiring cylinder cannot be identified reliably
when the conditions occur.

If more than one cylinder is misfiring, a separate DTC must be stored
to indicate that multiple cylinders are misfiring unless otherwise
allowed by this paragraph (h)(2).  When identifying multiple cylinder
misfire, the OBD system is not required to also identify using separate
DTCs each of the misfiring cylinders individually.  If more than 90
percent of the detected misfires occur in a single cylinder, an
appropriate DTC may be stored that indicates the specific misfiring
cylinder rather than storing the multiple cylinder misfire DTC.  If two
or more cylinders individually have more than 10 percent of the total
number of detected misfires, a multiple cylinder DTC must be stored.

Engine misfire malfunction criteria.

Misfire causing catalyst damage. The manufacturer must determine the
percentage of misfire evaluated in 200 revolution increments for each
engine speed and load condition that would result in a temperature that
causes catalyst damage. If this percentage of misfire is exceeded, it
shall be considered a malfunction that must be detected. For every
engine speed and load condition for which this percentage of misfire is
determined to be lower than five percent, the manufacturer may set the
malfunction criteria at five percent. The manufacturer may use a longer
interval than 200 revolutions but only for determining, on a given drive
cycle, the first misfire exceedance as provided in paragraph
(h)(2)(iv)(A) of this section. To do so, the manufacturer must
demonstrate that the interval is not so long that catalyst damage would
occur prior to the interval being elapsed.

Misfire causing emissions to exceed the applicable thresholds. The
manufacturer must determine the percentage of misfire evaluated in 1000
revolution increments that would cause emissions from an emissions
durability demonstration engine to exceed the emissions thresholds for
“other monitors” as shown in Table 2 of this paragraph (h) if that
percentage of misfire were present from the beginning of the test. If
this percentage of misfire is exceeded, regardless of the pattern of
misfire events (e.g., random, equally spaced, continuous), it shall be
considered a malfunction that must be detected. To establish this
percentage of misfire, the manufacturer must use misfire events
occurring at equally spaced, complete engine cycle intervals, across
randomly selected cylinders throughout each 1000-revolution increment.
If this percentage of misfire is determined to be lower than one
percent, the manufacturer may set the malfunction criteria at one
percent. The manufacturer may use a longer interval than 1000
revolutions. To do so, the manufacturer must demonstrate that the
strategy would be equally effective and timely at detecting misfire.

Engine misfire monitoring conditions.

 The OBD system must monitor continuously for misfire under the
following conditions: from no later than the end of the second
crankshaft revolution after engine start; during the rise time and
settling time for engine speed to reach the desired idle engine speed at
engine start-up (i.e., “flare-up” and “flare-down”); and, under
all positive torque engine speeds and load conditions except within the
engine operating region bound by the positive torque line (i.e., engine
load with the transmission in neutral), and the points represented by an
engine speed of 3000 rpm with the engine load at the positive torque
line and the redline engine speed with the engine’s manifold vacuum at
four inches of mercury lower than that at the positive torque line. For
this purpose, redline engine speed is defined as either the recommended
maximum engine speed as displayed on the instrument panel tachometer, or
the engine speed at which fuel shutoff occurs.

If an OBD monitor cannot detect all misfire patterns under all required
engine speed and load conditions as required by paragraph (h)(2)(iii)(A)
of this section, the OBD system may still be acceptable. The
Administrator will evaluate the following factors in making a
determination: the magnitude of the region(s) in which misfire detection
is limited; the degree to which misfire detection is limited in the
region(s) (i.e., the probability of detection of misfire events); the
frequency with which said region(s) are expected to be encountered
in-use; the type of misfire patterns for which misfire detection is
troublesome; and demonstration that the monitoring technology employed
is not inherently incapable of detecting misfire under the required
conditions (i.e., compliance can be achieved on other engines).  The
evaluation will be based on the following misfire patterns: equally
spaced misfire occurring on randomly selected cylinders; single cylinder
continuous misfire; and paired cylinder (cylinders firing at the same
crank angle) continuous misfire.

The manufacturer may use monitoring system that has reduced misfire
detection capability during the portion of the first 1000 revolutions
after engine start that a cold start emission reduction strategy is
active that reduces engine torque (e.g., spark retard strategies).  To
do so, the manufacturer must demonstrate that the probability of
detection is greater than or equal to 75 percent during the worst case
condition (i.e., lowest generated torque) for a vehicle operated
continuously at idle (park/neutral idle) on a cold start between 50 and
86 degrees Fahrenheit and that the technology cannot reliably detect a
higher percentage of the misfire events during the conditions.

The manufacturer may disable misfire monitoring or use an alternative
malfunction criterion when misfire cannot be distinguished from other
effects. To do so, the manufacturer must demonstrate that the
disablement interval or the period of use of an alternative malfunction
criterion is limited only to that necessary for avoiding false detection
and for one or more of the following operating conditions: rough road;
fuel cut; gear changes for manual transmission vehicles; traction
control or other vehicle stability control activation such as anti-lock
braking or other engine torque modifications to enhance vehicle
stability; off-board control or intrusive activation of vehicle
components or monitors during service or assembly plant testing;
portions of intrusive evaporative system or EGR monitors that can
significantly affect engine stability (i.e., while the purge valve is
open during the vacuum pull-down of a evaporative system leak check but
not while the purge valve is closed and the evaporative system is sealed
or while an EGR monitor causes the EGR valve to be cycled intrusively on
and off during positive torque conditions); or, engine speed, load, or
torque transients due to throttle movements more rapid than those that
occur over the FTP cycle for the worst case engine within each engine
family. In general, the Administrator will not approve disablement for
conditions involving normal air conditioning compressor cycling from
on-to-off or off-to-on, automatic transmission gear shifts (except for
shifts occurring during wide open throttle operation), transitions from
idle to off-idle, normal engine speed or load changes that occur during
the engine speed rise time and settling time (i.e., “flare-up” and
“flare-down”) immediately after engine starting without any vehicle
operator-induced actions (e.g., throttle stabs), or excess acceleration
(except for acceleration rates that exceed the maximum acceleration rate
obtainable at wide open throttle while the vehicle is in gear due to
abnormal conditions such as slipping of a clutch).

MIL activation and DTC storage for engine misfire causing catalyst
damage.

Pending DTCs. A pending DTC must be stored immediately if, during a
single drive cycle, the specified misfire percentage described in
paragraph (h)(2)(ii)(A) of this section is exceeded three times when
operating in the positive torque region encountered during a FTP cycle
or is exceeded on a single occasion when operating at any other engine
speed and load condition in the positive torque region defined in
paragraph (h)(2)(iii)(A) of this section. Immediately after a pending
DTC is stored pursuant to this paragraph, the MIL must blink once per
second at all times during the drive cycle that engine misfire is
occurring. The MIL may be deactivated during those times that misfire is
not occurring. If, at the time that a catalyst damaging misfire
malfunction occurs, the MIL is already activated for a malfunction other