Global Technical Regulation No. 5

Name:Global Technical Regulation No. 5
Description:OBD Systems for Road Vehicles.
Official Title:Technical Requirements for On-board Diagnostic Systems (OBD) for Road Vehicles.
Country:ECE - United Nations
Date of Issue:2006-11-15
Amendment Level:Amendment 1 of January 17, 2013
Number of Pages:98
Vehicle Types:Bus, Component, Heavy Truck
Subject Categories:Emissions and Fuel Consumption
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Keywords:

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Text Extract:

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ECE/TRANS/180/Add.5/Amend.1
January 17, 2013
GLOBAL REGISTRY
Created on November 18, 2004, Pursuant to Article 6 of the
AGREEMENT CONCERNING THE ESTABLISHING OF GLOBAL TECHNICAL
REGULATIONS FOR WHEELED VEHICLES, EQUIPMENT AND PARTS WHICH
CAN BE FITTED AND/OR BE USED ON WHEELED VEHICLES
(ECE/TRANS/132 and Corr.1)
DONE AT GENEVA ON JUNE 25, 1998
Addendum:
GLOBAL TECHNICAL REGULATION NO. 05
TECHNICAL REQUIREMENTS FOR ON-BOARD
DIAGNOSTIC SYSTEMS (OBD) FOR ROAD VEHICLES
(ESTABLISHED IN THE GLOBAL REGISTRY ON NOVEMBER 12, 2009)
Incorporating:
Corrigendum 1
dated March 5, 2010
Amendment 1
dated January 17, 2013

5.
PERFORMANCE REQUIREMENTS
6.
DEMONSTRATION REQUIREMENTS
7.
TEST PROCEDURES
8.
DOCUMENTATION REQUIREMENTS
8.1.
Treatment of OBD confidential documentation
9.
ANNEXES
ANNEX 1
Reference standard documents
MODULE B: EMISSION-RELATED OBD FOR HEAVY-DUTY DIESEL ENGINE SYSTEMS
1. PURPOSE
2. SCOPE
3. DEFINITIONS
4. GENERAL REQUIREMENTS
4.1.
Application for certification of an OBD system
4.2.
Monitoring requirements
4.3.
Requirements for recording OBD information
4.4.
Requirements for erasing OBD information
4.5.
Requirements for malfunction classification
4.6.
Alert system
4.7.
OBD diagnostic information
4.8.
Electronic security
5. PERFORMANCE REQUIREMENTS
5.1.
Thresholds
5.2.
Temporary disablement of the OBD system
6. DEMONSTRATION REQUIREMENTS
6.1.
Emission-OBD diagnostic family
6.2.
Procedures for demonstrating the malfunction classification
6.3.
Procedures for demonstrating the OBD performance
6.4.
Certification of an OBD system containing deficiencies
6.5.
Direct certification of the installation of an OBD system on a heavy-duty vehicle
7. TEST PROCEDURES
7.1.
Testing process
7.2.
Applicable tests
7.3.
Test reports

GLOBAL TECHNICAL REGULATION NO. 05
A. JUSTIFICATION AND TECHNICAL RATIONALE
1. INTRODUCTION
This global technical regulation (GTR) establishes technical requirements for on-board
diagnostic systems (OBD) for road vehicles. Currently, the GTR is directed only at OBD
requirements for heavy-duty engines/vehicles necessary to maintain emissions-related
performance (i.e. emissions-OBD). Nonetheless, as discussed in more detail below, the GTR
has been structured in a manner that facilitates a wider application of OBD to other vehicle
systems in the future.
In brief, the GTR sets forth OBD performance requirements to which engine manufacturers
must demonstrate compliance to certification authorities. The GTR also sets forth a basic set
of demonstration requirements for manufacturers so that compliance can be demonstrated in
a consistent manner. Also included are requirements to standardise the communication of
on-board information to off-board devices to assist in maintenance of the increasingly
complex modern diesel engines, and to facilitate the future use of OBD as a roadworthiness
indicator for heavy-duty vehicles.
Of particular importance with respect to the use of OBD as a roadworthiness indicator is the
introduction, with this GTR, of a failure severity indication via the dashboard malfunction
warning signal (malfunction indicator). The failure severity indication is achieved in two ways.
Firstly, the GTR requires the use of a separate and dedicated malfunction indicator to indicate
a malfunction in the engine and emissions control system that results in an increase in
emissions. Other failures that previously may have been communicated via a shared
indicator must now use a separate and discreet indicator. Secondly, the GTR requires that
the effect of malfunctions be assessed as part of the design function and that their effect be
designated to a specific level within a 3-tier classification. Upon malfunction detection, the
malfunction indicator is required to communicate in a unique way depending on which of the
three tiers to which the detected malfunction has been designated. While the requirements
for the malfunction indicator provide for each of these failure levels to be discernible, only the
upper two failure levels are automatically indicated to the driver. This has been termed a
"discriminatory display" strategy as it discriminates between three possible severities of
malfunctions when indicating them via the malfunction indicator. This new requirement is
intended to allow vehicle operators, maintenance staff, inspectors and enforcement
authorities to make an informed decision with regard the roadworthiness of the vehicle.
Nevertheless, not all Contracting Parties may wish to apply this approach. Therefore, the
GTR provides for a malfunction indicator that would use a non-discriminatory display strategy
(i.e. one that would communicate all malfunctions regardless of their severity in the same
manner via the malfunction indicator) for regions that may find it more suitable than this new
discriminatory display model.

OBD is likely to become increasingly important in future roadworthiness/inspection and
maintenance procedures and the GTR reflects this expectation. It provides for standardised
OBD data to be accessible from a common OBD access port. Telematic functions are being
offered increasingly to improve the efficiency of working vehicles and, whilst this functionality
is not included in the current version of the GTR, it nonetheless anticipates such a possible
future need. The work of ISO is such that, should there be a future political or commercial
need for this technology, the impact on the design of the OBD systems, and on manufacturing
industry, will be minimised.
2. PROCEDURAL BACKGROUND
During the one-hundred-and-twenty-sixth session of WP.29 on March 2002, the Executive
Committee (AC.3) of the 1998 Global Agreement (1998 Agreement) adopted a programme of
work, which includes the development of a global technical regulation (GTR) concerning
on-board diagnostic systems for heavy-duty vehicles and engines.
An informal working group − the WWH-OBD working group − was actually established in
September 2001, further to a proposal from the GRPE Chair in May 2001, to incorporate
heavy-duty OBD into the GRPE agenda. Japan volunteered to lead the group.
The working group was instructed that the OBD system should detect failures from the engine
itself, as well as from the exhaust after-treatment systems fitted downstream of the engine,
and from the package of information exchanged between the engine electronic control unit(s)
and the rest of vehicle and/or powertrain.
The working group was also instructed to base the OBD requirements on the technologies
expected to be industrially available at the time the GTR would be enforced, and to take into
account both the expected state of electronics in the years 2005-2008 and the expected
newest engine and after-treatment technologies.
In November 2003, AC.3 further directed the working group to structure the GTR in such a
manner as to enable its future extension to other functions of the vehicle. In so doing, AC.3
did not revise the scope of the task given to the working group (i.e. the scope remained
emissions-related heavy-duty OBD). Hence, the structure of the GTR was adapted as
described above.

Table A.1.
Application Dates of European OBD Directives
Vehicle category
Date from which all new vehicles shall
be equipped with an OBD system
complying with the requirements of
Directive 70/220/EEC (as amended)
Positive-ignition (petrol) engines:
Category M (i.e. passenger cars) ≤ 2,500kg:
Category N Class 1 (i.e. goods vehicles ≤
1,305kg):
Category M > 2,500kg:
Category N Classes II and III (i.e. goods vehicles
> 1,305kg and ≤ 3,500kg):
January 1, 2001
January 1, 2002
Positive-ignition engines running permanently or part-time on LPG or NG:
Category M ≤ 2,500kg and Category N Class I January 1, 2006
Category M > 2,500kg and Category N
Classes II and III:
January 1, 2007
Compression-ignition (diesel) engines:
Category M ≤ 2,500kg and those designed to
carry ≤ 6 occupants:
Category M designed to carry > 6 occupants:
Category N Class 1:
Category M > 2,500kg:
Category N Classes II and III:
January 1, 2004
January 1, 2006
January 1, 2007
Directive 1999/96/EC (amending Directive 88/77/EEC ) laid down the Euro 3, Euro 4 and
Euro 5 pollutant emission limits. Article 4 of that Directive required the European Commission
to bring forward a proposal to introduce OBD for heavy-duty vehicles and engines in parallel
with the Euro 4 stage of emission limits. In response to this request, Directive 2005/55/EC
lays down the fundamental elements relating to OBD for heavy-duty vehicles and engines,
i.e. the formal structure of the requirements and the OBD threshold limits. This is
complemented by Directive 2005/78/EC which provides the technical requirements for
implementing the fundamental requirements of Directive 2005/55/EC.

Because computer and electronic systems are difficult to diagnose and repair when not
functioning properly, most manufacturers of vehicles, trucks, and engines have incorporated
on-board diagnostic (OBD) systems into their products. These OBD systems are capable of
identifying improper functioning and help to pinpoint where the malfunction is occurring. This
serves to inform both the driver of the vehicle that repair is needed, and the repairer of the
vehicle what needs to be repaired. In the heavy truck industry, these OBD systems have
been geared traditionally toward detecting problems that cause drivability and/or fuel
economy related effects. Understandably, the primary objective of these systems has been to
protect against performance problems that might result in customer dissatisfaction. The
emissions-related OBD requirements in this GTR would build on the efforts already
undertaken by industry to ensure that key emission related components will be monitored and
that the diagnosis and repair of those components will be as efficient and cost effective as
possible. The requirements of this GTR will ensure that malfunctions that are purely
emissions-related (i.e. those types of malfunctions that could result in high emissions without
a corresponding adverse drivability or fuel economy impact) will be detected and
communicated to the driver and the repair technician. The result being that the air quality
benefits expected from the regulatory programs of the Contracting Parties will be fully
realised.
An OBD system meeting the emissions-OBD requirements of this GTR would be expected to
monitor the engine's electronic sensors and actuators and to monitor the exhaust after
treatment devices for their proper operation. Upon detecting any problems, the driver would
be notified of the need to seek repair and pertinent information would be stored in the engine
computer for retrieval by the repair professional. As a result, emissions-related problems are
identified, their presence is communicated to the driver, repair is sought out, and proper repair
is completed.
Further, the malfunction classification of the GTR will provide roadworthiness inspectors with
the ability to determine not only the presence of malfunctions but also the severity of their
emissions impact. This will allow for certain regions, depending on their air quality needs, to
impose repair requirements and/or fees for only those malfunctions meeting the appropriate
severity. This is important since many malfunctions that will be detected by an OBD system
meeting the requirements of this GTR will result in only minor emissions increases and may
not cause emissions to exceed the regulated emissions limits.
4.2. Economic Impacts
The requirements set forth in the emissions-related Paragraph of the regulation are believed
to be technologically feasible in the timeframe expected for their implementation. The
WWH-OBD working group consists of both regulators and industry representatives. General
agreement has been reached on the content of the GTR which should equate to general
agreement on the feasibility of its requirements. Nonetheless, authorities are encouraged to
carefully consider the costs, technological feasibility, fuel quality, and possible safety
concerns that may be unique to their region when considering adoption of this GTR.
Designing and developing OBD systems that meet the emissions-OBD requirements of this
GTR will cost industry considerable money. The cost of maintaining and repairing
malfunctions identified by the OBD system will impact on industry, operators of heavy-duty
vehicles and the general public. As noted in Paragraph 3. above, many Contracting Parties
have or are developing OBD requirements analogous to those in this GTR. Having one set of
OBD requirements that would apply to all regions represented by the Contracting Parties
would save industry considerable money relative to the situation they face currently with
separate requirements in each region.

As an additional example, a certification authority in a Contracting Party may determine
through in-service testing or any other regulatory measure applicable in the region in which
that authority is responsible that, in the case of a vehicle/engine type or family which has
been approved according to this GTR, a malfunction or malfunctions should be re-classified
from their initial approved classification. In such a case, the Contracting Party would, where
applicable, inform the manufacturer of the vehicle/engine type or family in question and
undertake any applicable measures defined according to the rules or regulations applying this
Regulation in that Contracting Party. If the Contracting Party undertakes any actions with the
manufacturer in question, it is recommended that the Contracting Party would inform other
Contracting Parties to this global technical regulation of the issue and any consequential
actions it plans or has completed. On that basis, other Contracting Parties might decide to
require a manufacturer of the same vehicle/engine type or family to undertake a similar
re-classification for those same vehicles/engines within that Contracting Party.
While these examples speak specifically to malfunction re-classification, similar examples
could be given for other forms of post-approval fixes meant to correct elements of the OBD
system that are not working as designed or as intended, whether they should be identified by
the certification authority or the manufacturer. For example, an OBD monitor that never
operates − whether due to poor design, a software glitch, or some other unforeseen
circumstances − in one Contracting Party would, presumably, not operate in other Contracting
Parties. It is recommended that Contracting Parties inform other Contracting Parties to this
GTR of such issues and any consequential actions it plans or has completed so that other
Contracting Parties have the opportunity to consider the issue.
When considering adopting this GTR into its national or regional regulations, Contracting
Parties are encouraged also to consider implementing specifications concerning:
(a)
(b)
the availability of service and repair information. Such information might include repair
manuals, diagnostic tools, relevant computer software, training materials, or other
special tools provided by engine manufacturers to their authorised dealer network.
Such information is important to ensure that OBD identified malfunctions can be
repaired by service personnel.
to the extent appropriate according to the laws of the Contracting Parties, the
availability of OBD related information for verifying that replacement parts, which are
critical to the correct functioning of the OBD system, are compatible with the vehicle
OBD system.
6. POSSIBLE FUTURE EXTENSIONS OF THE GTR
6.1. Future Extensions to other Functions of the Vehicle
As mentioned in Paragraph 2., AC.3 directed the working group to structure the GTR in such
a manner as to enable its future extension to other functions of the vehicle.
A modular structure has been adopted to achieve that requirement, where the scope and
application of this GTR could be easily extended as summarised in the following table:

Consequently, GRPE endorsed the recommendation of the WWH-OBD working group to
move towards the application of a common standard in a step-wise approach within this GTR.
In a first application of this GTR, Contracting Parties would accept the use of any of either
ISO/PAS 27145 (CAN-based) or SAE J1939-73 (but recognising that these standards must
be adapted to fully meet the requirements of this GTR) or ISO 27145 (TCP/IP-based).
In a future step, possibly aligned with Step 3 mentioned in Section 6.3 below, it may be
appropriate for Contracting Parties to apply the use of just ISO 27145. However, in
consideration of regional legislation that would require the use of just ISO 27145, Contracting
Parties are encouraged to consider the timing of such legislation with respect to adequate
industry leadtime, and the impact on the automotive industry sectors operating under the
umbrella of "the automotive industry."
6.3. Harmonisation of the Emission OBD Threshold Limits (OTLs)
Harmonised OBD performance requirements will evolve with the harmonisation of the
test-cycles (for exhaust emissions and for emission related OBD), the emission limits and the
process for calculating the OTLs.
The following table summarises the recommended major steps towards fully harmonised
OBD performance requirements:
Table A.2
Steps Towards OBD Harmonisation
Step 1
Step 2
Step 3
Test-cycles (emissions and Non-harmonised
OBD)
or harmonised
Harmonised
Harmonised
Emission limits
Non harmonised
Non harmonised
Harmonised
OTLs calculation process
Non harmonised
Harmonised
Harmonised
OTLs
Step 1
Regionally
defined
Regionally calculated
with the harmonised
OTLs calculation
process
Harmonised
In the first step, OTLs are not harmonised world-wide and the process for defining the OTLs is
not harmonised.
The Contracting Parties decide the OTLs and whether or not they want to couple the
introduction of this GTR in their own legislation with that of the "WHDC" GTR. In that case,
the test-cycles used in this GTR are harmonised world-wide. In the other case, they are not
harmonised.
The requirements of this first step are prescribed in Module B of this GTR.

MODULE A
GENERIC OBD PROVISIONS
1. PURPOSE
2. SCOPE
This module prescribes the general requirements for on-board diagnostic (OBD) systems to
detect, and, if applicable, record and/or communicate failures of specific vehicle and engine
systems whether they affect the environmental or safety performance of these systems, as
described in the specific modules of this GTR.
In addition, this module specifies generic elements concerning the OBD system to facilitate
the diagnosis and maintenance of specific vehicle and engine systems and the possible
enforcement of road-worthiness measures without containing mandatory prescriptions for this
purpose.
This module applies to OBD systems for vehicles of Categories 1-2 and 2
speed exceeding 25km/h and having a maximum mass exceeding 3.5t.
, having a design
3. DEFINITIONS
3.1. "Alert system" means a system on-board the vehicle which informs the driver of the vehicle
or any other interested party that the OBD system has detected a malfunction.
3.2. "Authority" (see "certification authority" and "Contracting Party").
3.3. "Certification authority" means the authority that grants the compliance certification of an
OBD system according to this GTR. Per extension, it means also the technical service that
has been accredited to evaluate the technical compliance of the OBD system.
3.4. "Component monitoring" means the monitoring of input components for electrical circuit
failures and rationality failures and monitoring of output components for electrical circuit
failures and functionality failures.
3.5. "Contracting Party" means the party signatory to the 1998 Agreement.
3.6. "Electrical circuit failure" means a malfunction (e.g. open circuit or short circuit) that leads
to the measured signal (i.e. voltages, currents, frequencies, etc.) being outside the range
where the transfer function of the sensor is designed to operate.
3.7. "Functionality failure" means a malfunction where an output component does not respond
to a computer command in the expected way.
3.8. "Heavy-duty vehicle" means a power driven vehicle of Category 1-2 or 2, as defined in
Special Resolution No. 1 (S.R.1), which has a design speed exceeding 25km/h and a
maximum mass exceeding 3,500kg.

4.3. Alert System
Requirements applicable to alert systems are specific to each OBD system and are
prescribed in the specific modules of this GTR.
The failure of a component of the alert system shall not cause the OBD system to stop
functioning.
4.3.1. Malfunction Indicator (MI)
Requirements applicable to the malfunction indicator (MI), including its activation/deactivation
schemes, are specific to each OBD system and are prescribed in the specific modules of this
GTR.
The MI shall be perceptible by the driver from the driver's seat position.
4.4. OBD Diagnostic Information
Requirements applicable to OBD information (e.g. alert system status, OBD readiness,
malfunction indication, diagnostic trouble codes, etc.) are specific to each OBD system and
are prescribed in the specific modules of this GTR.
Nevertheless, communication and access to OBD information shall, at a minimum, fulfil the
requirements of the following sub-paragraphs.

4.4.1.1. Controller Area Network (CAN) Based Wired Communication
The communication speed on the wired data link of the OBD system shall be either 250 kbps
or 500 kbps.
It is the manufacturer's responsibility to select the baud-rate and to design the OBD system
according to the requirements specified in the standards mentioned in Annex 1, and referred
to in the specific modules. The OBD system shall be tolerant against the automatic detection
between these two baud-rates exercised by the external test equipment.
The connection interface between the vehicle and the external diagnostic test equipment
(e.g. scan-tool) shall be standardised and shall meet all of the requirements of
ISO 15031-3:2004 Type A (12 VDC power supply), Type B (24 VDC power supply) or
SAE J1939-13 (12 or 24 VDC power supply).
4.4.1.2. (Reserved for TCP/IP (Ethernet) Based Wired Communication.)
4.4.1.3. Connector Location
The connector shall be located in the driver's side foot-well region of the vehicle interior in the
area bound by the driver's side of the vehicle and the driver's side edge of the centre console
(or the vehicle centreline if the vehicle does not have a centre console) and at a location no
higher than the bottom of the steering wheel when in the lowest adjustable position. The
connector may not be located on or in the centre console (i.e. neither on the horizontal faces
near the floor-mounted gear selector, parking brake lever, or cup holders nor on the vertical
faces near the stereo/radio, climate system, or navigation system controls). The location of
the connector shall be capable of being easily identified and accessed (e.g. to connect an
off-board tool). For vehicles equipped with a driver's side door, the connector shall be
capable of being easily identified and accessed by someone standing (or "crouched") outside
the driver's side of the vehicle with the driver's side door open.
Contracting Parties may allow the certification authority to approve upon request of the
manufacturer an alternative location provided the installation position shall be easily
accessible and protected from accidental damage during normal conditions of use.
If the connector is covered or located in a specific equipment box, the cover or the
compartment door must be removable by hand without the use of any tools and be clearly
labelled "OBD" to identify the location of the connector.
The manufacturer may equip vehicles with additional diagnostic connectors and data-links for
manufacturer-specific purposes other than the required OBD functions. If the additional
connector conforms to one of the standard diagnostic connectors allowed in Annex 1, only the
connector required by this GTR shall be clearly labelled "OBD" to distinguish it from other
similar connectors.
4.4.2. Erasing OBD Information
The OBD system shall clear recorded OBD information in accordance with the provisions of
the specific modules, when this request is provided via the external repair test equipment
according to the standards of Annex 1 to this module.
OBD information shall not be erased by disconnection of the vehicle's battery(s).

8.1. Treatment of OBD Confidential Documentation
The content of the second part of the documentation package shall be treated as strictly
confidential. It may nevertheless be shared with other certification authorities according to the
laws and regulations of each Contracting Party.
9. ANNEXES
Annex 1 contains the references to the industry standards that are to be used in accordance
to the provisions of this GTR to provide the serial communications interface to the
vehicle/engine. There are two allowed solutions identified:
(a)
(b)
ISO 27145 with either ISO 15765-4 (CAN based) with either ISO 15765-4 (CAN based)
or with ISO 13400 (TCP/IP based)
SAE J1939-73.
In addition there are other ISO or SAE standards that are applicable in accordance with the
provisions of this gtr.

1. PURPOSE
2. SCOPE
MODULE B
EMISSION–RELATED OBD FOR HEAVY-DUTY DIESEL ENGINE SYSTEMS
This module complements the generic provisions specified in Module A by prescribing
additional specific requirements for OBD systems to detect record and communicate
emission-related malfunctions from heavy-duty diesel engine systems that would affect the
environmental performance of those systems.
This module specifies the elements concerning the emission-related OBD system to facilitate
the diagnosis and maintenance of the engine system and the possible enforcement of
road-worthiness measures.
This module applies to the emission related OBD system for diesel fuelled engines equipped
on vehicles of Categories 1-2 and 2 , having a design speed exceeding 25km/h and having a
maximum mass exceeding 3.5t.
This module applies also to the installation of that OBD system, when a Contracting Party
requires certification of that installation.
3. DEFINITIONS
3.1. "Calibration verification number" means the number that is calculated and reported by the
engine system to validate the calibration/software integrity.
3.2. "Component monitoring" refers in the context of this module to components that are
electrically connected to the controller(s) of the engine system. (Definition of Module A further
qualified ).
3.3. "Confirmed and active DTC" means a DTC that is stored during the time the OBD system
concludes that a malfunction exists.
3.4. "Continuous-MI" means the malfunction indicator showing a steady indication at all times
while the key is in the on (run) position with the engine running (ignition on − engine on).
3.5. "Deficiency" means an OBD monitoring strategy or other OBD feature that does not meet all
the detailed requirements of Module A or of this module.
3.6. "Diagnostic trouble code (DTC)" means a numeric or alphanumeric identifier which
identifies or labels a malfunction.
3.7. "Emission OBD family" means a manufacturer's grouping of engine systems having
common methods of monitoring/diagnosing emission-related malfunctions.

3.18. "On-demand-MI" means the malfunction indicator showing a steady indication in response to
a manual demand from the driving position when the key is in the on (run) position with the
engine off (ignition on − engine off).
3.19. "Operating sequence" means a sequence consisting of an engine start-up, an operating
period, an engine shut-off, and the time until the next start-up, where a specific OBD monitor
runs to completion and a malfunction would be detected if present.
3.20. "Pending DTC" means a DTC that is stored by the OBD system because a monitor has
detected a situation where a malfunction may be present during the current or last completed
operating sequence.
3.21. "Performance monitoring" means malfunction monitoring that consists of functionality
checks and monitoring parameters that are not correlated to emission thresholds. Such
monitoring is typically done on components or systems to verify that they are operating within
the proper range (e.g. differential pressure in case of a DPF).
3.22. "Potential DTC" means a DTC that is stored by the OBD system because a monitor has
detected a situation where a malfunction may be present but requires further evaluation to be
confirmed. A potential DTC is a pending DTC which is not a confirmed and active DTC.
3.23. "Previously active DTC" means a formerly confirmed and active DTC that remains stored
after the OBD system has concluded that the malfunction that caused the DTC is no longer
present.
3.24. "Readiness" means a status indicating whether a monitor or a group of monitors have run
since the last erasing by an external request or command (for example through an OBD
scan-tool).
3.25. "Scan-tool" means an external test equipment used for standardised off-board
communication with the OBD system in accordance with the requirements of this module.
3.26. "Short-MI" means the malfunction indicator showing a steady indication from the time the key
is moved to on (run) position and the engine is started (ignition on − engine on) and
extinguishing after 15s or the key is moved to off, whichever occurs first.
3.27. "Software calibration identification" means a series of alphanumeric characters that
identifies the emission-related calibration/software version(s) installed in the engine system.
3.28. "Total functional failure monitoring" means monitoring a malfunction which is leading to a
complete loss of the desired function of a system.
3.29. "Warm-up cycle" means sufficient engine operation such that the coolant temperature has
risen by at least 22K (22°C/40°F) from engine starting and reaches a minimum temperature of
333K (60°C/140°F)

4.1. Application for Certification of an OBD System
4.1.1. Primary Certification
The manufacturer of an engine system may apply for the certification of its OBD system in
one of the three following manners:
(a)
(b)
The manufacturer of an engine system applies for the certification of an individual OBD
system by demonstrating that OBD system complies with all the provisions of
Modules A and B of the present GTR.
The manufacturer of an engine system applies for the certification of an emission-OBD
family by demonstrating that the OBD-parent engine system of the family complies with
all the provisions of Modules A and B of the present GTR.
The manufacturer of an engine system applies for the certification of an OBD system by
demonstrating that OBD system meets the criteria for belonging to an emission-OBD family
that has already been certified.
4.1.2. Extension/Modification of an Existing Certificate
4.1.2.1. Extension to Include a New Engine System into an Emission-OBD Family
At the request of the manufacturer and upon approval of the certification authority, a new
engine system may be included as a member of a certified emission-OBD family if all the
engine systems within the so-extended emission-OBD family still have common methods of
monitoring/diagnosing emission-related malfunctions.
If all OBD elements of design of the OBD-parent engine system are representative of those of
the new engine system, then the OBD-parent engine system shall remain unchanged and the
manufacturer shall modify the documentation package according to Paragraph 8. of this
module.
If the new engine system contains elements of design that are not represented by the
OBD-parent engine system but itself would represent the whole family, then the new engine
system shall become the new OBD-parent engine system. In this case the new OBD
elements of design shall be demonstrated to comply with the provisions of Modules A and B
of this GTR, and the documentation package shall be modified according to Paragraph 8. of
this module.
4.1.2.2. Extension to Address a Design Change that Affects the OBD System
At the request of the manufacturer and upon approval of the certification authority, an
extension of an existing certificate may be granted in the case of a design change of the OBD
system if the manufacturer demonstrates that the design changes comply with the provisions
of Modules A and B of this GTR.
The documentation package shall be modified according to Paragraph 8. of this module.
If the existing certificate applies to an emission-OBD family, the manufacturer shall justify to
the certification authority that the methods of monitoring/diagnosing emission-related
malfunctions are still common within the family and that the OBD-parent engine system
remains representative of the family.

4.2.1.1. Correlation to Actual Emissions
In the case of emission threshold monitoring, a correlation to test-cycle specific emissions
shall be required. This correlation would typically be demonstrated on a test engine in a
laboratory setting.
In all other monitoring cases (i.e. performance monitoring, total functional failure monitoring,
or component monitoring), no correlation to actual emissions is necessary. However, the
certification authority may request test data to verify the classification of the malfunction
effects as described in Paragraph 6.2. of this module.
Examples: (i)
(ii)
An electrical malfunction may not require a correlation because this is a
yes/no malfunction.
A DPF malfunction monitored via delta pressure may not require a
correlation because it anticipates a malfunction.
If the manufacturer demonstrates, according to the demonstration requirements of this
module, that emissions would not exceed the OBD threshold limits upon total failure or
removal of a component or system, a performance monitoring of this component or system
shall be accepted.
When a tailpipe emission sensor is used for monitoring the emissions of a specific pollutant all
other monitors may be exempted from further correlation to the actual emissions of that
pollutant. Nevertheless, such exemption shall not preclude the need to include these
monitors, using other monitoring techniques, as part of the OBD system as the monitors are
still needed for the purpose of malfunction isolation.
A malfunction shall always be classified according to Paragraph 4.5. based on its impact on
emissions, regardless of the type of monitoring used to detect the malfunction.
4.2.2. Component Monitoring (Input/Output Components/Systems)
In the case of input components that belong to the engine system, the OBD system shall at a
minimum detect electrical circuit failures and, where feasible, rationality failures.
The rationality failure diagnostics shall then verify that a sensor output is neither
inappropriately high nor inappropriately low (i.e. there shall be "two-sided" diagnostics).
To the extent feasible, and with the agreement of the certification authority, the OBD system
shall detect separately, rationality failures (e.g. inappropriately high and inappropriately low),
and electrical circuit failures (e.g. out-of-range high and out-of-range low). Additionally,
unique DTCs for each distinct malfunction (e.g. out-of-range low, out-of-range high and
rationality failure) shall be stored.
In the case of output components that belong to the engine system, the OBD system shall at
a minimum detect electrical circuit failures, and, where feasible, if the proper functional
response to computer commands does not occur.

4.2.3. Monitoring Frequency
Monitors shall run continuously, at any time where the monitoring conditions are fulfilled, or
once per operating sequence (e.g. for monitors that lead to an increase of emission when it
runs).
When a monitor does not run continuously, the manufacturer shall clearly inform the
certification authority and describe the conditions under which the monitor runs.
At the request of the manufacturer, the certification authority may approve monitors that do
not run continuously, the manufacturer shall clearly inform the certification authority and
describe the conditions under which the monitor runs and justify the proposal by appropriate
design elements (such as good engineering practice).
The monitors shall run during the applicable OBD test-cycle as specified in Paragraph 7.2.2.
A monitor shall be regarded as running continuously, if it samples at a rate not less than twice
per second and concludes the presence or the absence of the failure relevant to that monitor
with 15s. If a computer input or output component is sampled less frequently than twice per
second for engine control purpose, a monitor shall also be regarded as running continuously,
if the system concludes the presence or the absence of the failure relevant to that monitor
each time sampling occurs.
For components or systems monitored continuously, it is not required to activate an output
component/system for the sole purpose of monitoring that output component/system.

4.5. Requirements for Malfunction Classification
Malfunction classification specifies the class to which a malfunction is assigned when such a
malfunction is detected, according to the requirements of Paragraph 4.2. of this module.
A malfunction shall be assigned to one class for the actual life of the vehicle unless the
authority that granted the certificate or the manufacturer determines that reclassification of
that malfunction is necessary.
If a malfunction would result in a different classification for different regulated pollutant
emissions or for its impact on other monitoring capability, the malfunction shall be assigned to
the class that takes precedence in the discriminatory display strategy.
If an MECS is activated as a result of the detection of a malfunction, this malfunction shall be
classified based on either the emission impact of the activated MECS or its impact on other
monitoring capability. The malfunction shall then assigned to the class that takes precedence
in the discriminatory display strategy.
4.5.1. Class A Malfunction
A malfunction shall be identified as Class A when the relevant OBD threshold limits (OTLs)
are assumed to be exceeded.
It is accepted that the emissions may not be above the OTLs when this class of malfunction
occurs.
4.5.2. Class B1 Malfunction
A malfunction shall be identified as Class B1 where circumstances exist that have the
potential to lead to emissions being above the OTLs but for which the exact influence on
emission cannot be estimated and thus the actual emissions according to circumstances may
be above or below the OTLs.
Examples of Class B1 malfunctions may include malfunctions detected by monitors that infer
emission levels based on readings of sensors or restricted monitoring capability.
Class B1 malfunctions shall include malfunctions that restrict the ability of the OBD system to
carry out monitoring of Class A or B1 malfunctions.
4.5.3. Class B2 Malfunction
A malfunction shall be identified as Class B2 when circumstances exist that are assumed to
influence emissions but not to a level that exceeds the OTL.
Malfunctions that restrict the ability of the OBD system to carry out monitoring of Class B2
malfunctions of shall be classified into Class B1 or B2.

At key on, engine off, a single MI activation strategy is required. This strategy is described in
Paragraph 4.6.4.
Figures B1 and B2 illustrate the prescribed activation strategies at key on, engine on or off.
ENGINE ON
ENGINE OFF
a) MI bulb) functioning, no malfunction to report, and the readiness of all monitored
components "complete".
b) MI (bulb) functioning, no malfunction to report, and at least one component with
readiness "not complete".
c) MI (bulb) non operational
Figure B1
Bulb Test and Readiness Indication

4.6.3. MI Activation at "Engine On"
When the key is placed in the on position and the engine is started (engine on), the MI shall
be commanded off unless the provisions of Paragraph 4.6.3.1. and/or Paragraph 4.6.3.2.
have been met.
4.6.3.1. Discriminatory Display Strategy
For the purpose of activating the MI, continuous-MI shall take precedence to short-MI and
on-demand-MI. For the purpose of activating the MI, short-MI shall take precedence to
on-demand-MI.
4.6.3.1.1. Class A Malfunctions
The OBD system shall command a continuous-MI upon storage of a confirmed DTC
associated with a Class A malfunction.
4.6.3.1.2. Class B Malfunctions
The OBD system shall command a "short-MI" at the next key-on event following storage of a
confirmed and active DTC associated with a Class B malfunction.
Whenever a B1 counter reaches 200 hours, the OBD system shall command a
continuous-MI.
4.6.3.1.3. Class C Malfunctions
The manufacturer may make available information on Class C malfunctions through the use
of an on-demand-MI which shall be available until the engine is started.
4.6.3.1.4. MI De-activation Scheme
The "continuous-MI" shall switch to a "short-MI" if a single monitoring event occurs and the
malfunction that originally activated the continuous-MI is not detected during the current
operating sequence and a continuous-MI is not activated due to another malfunction.
The "short-MI" shall be deactivated if the malfunction is not detected during 3 subsequent
sequential operating sequences following the operating sequence when the monitor has
concluded the absence of the considered malfunction and the MI is not activated due to
another Class A or B malfunction.
Figures 1, 4 and 4bis in Annex 2 illustrate respectively the short and continuous MI
deactivation in different use-cases.
4.6.3.2. Non-discriminatory Display Strategy
The OBD system shall command a continuous-MI upon storage of a confirmed and active
DTC associated with a Class A, B or C malfunction.
4.6.3.2.1. MI De-activation Scheme
The "continuous-MI" shall be deactivated if the malfunction is not detected during
3 subsequent sequential operating sequences and the MI is not activated due to any other
malfunction.

4.6.4.2.3. Activation Mode 3 − "Short-MI"
The MI shall blink for three flashes if the OBD system would command a short-MI according
to the discriminatory display strategy described in Paragraph 4.6.3.1.
4.6.4.2.4. Activation Mode 4 − "Continuous-MI"
The MI shall remain continuously ON ("continuous-MI") if the OBD system would command a
continuous-MI according to the discriminatory display strategy described in
Paragraph 4.6.3.1.
4.6.5. Counters Associated with Malfunctions
4.6.5.1. MI Counters
4.6.5.1.1. Continuous-MI Counter
The OBD system shall contain a continuous-MI counter to record the number of hours during
which the engine has been operated while a continuous-MI is activated.
The continuous-MI counter shall count up to the maximum value provided in a 2 byte counter
with 1 hour resolution and hold that value unless the conditions allowing the counter to be
reset to zero are met.
The continuous-MI counter shall operate as follows:
(a)
(b)
(c)
(d)
(e)
if starting from zero, the continuous-MI counter shall begin counting as soon as a
continuous-MI is activated.
the continuous-MI counter shall halt and hold its present value when the continuous-MI
is no longer activated.
the continuous-MI counter shall continue counting from the point at which it had been
held if a malfunction that results in a continuous-MI is detected within 3 operating
sequences.
the continuous-MI counter shall start again counting from zero when a malfunction that
results in a continuous-MI is detected after 3 operating sequences since the counter
was last held.
the continuous-MI counter shall be reset to zero when:
(i)
(ii)
no malfunction that results in a continuous-MI is detected during 40 warm-up
cycles or 200 engine operating hours since the counter was last held whichever
occurs first; or
the OBD scan tool commands the OBD System to clear OBD information.
Figure C1 illustrates the principle of the continuous-MI counter and Annex 2 contains
examples that illustrate the logic.

4.6.5.1.2. Cumulative Continuous-MI Counter
Figure C2
Illustration of the B1 Counter Activation Principles
The OBD system shall contain a cumulative continuous-MI counter to record the cumulative
number of hours during which the engine has been operated over its life while a
continuous-MI is activated.
The cumulative continuous-MI counter shall count up to the maximum value provided in a
2-byte counter with 1 hour resolution and hold that value.
The cumulative continuous-MI counter shall not be reset to zero by the engine system, a scan
tool or a disconnection of a battery.
The cumulative continuous-MI counter shall operate as follows:
(a)
(b)
(c)
the cumulative continuous-MI counter shall begin counting when the continuous-MI is
activated.
the cumulative continuous-MI counter shall halt and hold its present value when the
continuous-MI is no longer activated.
the cumulative continuous-MI counter shall continue counting from the point it had been
held when a continuous-MI is activated.
Figure C1 illustrates the principle of the cumulative continuous-MI counter and Annex 2
contains examples that illustrate the logic.

4.7. OBD Diagnostic Information
4.7.1. Recorded Information
The information recorded by the OBD system shall be available upon off-board request in the
following manner:
(a)
(b)
(c)
information about the engine state;
information about active emission-related malfunctions;
information for repair.
4.7.1.1. Information about the Engine State
This information will provide an enforcement agency with the malfunction indicator status
and associated data (e.g. continuous-MI counter, readiness).
The OBD system shall provide all information (according to the applicable standard set in
Module A Annex 1) for the external roadside check test equipment to assimilate the data and
provide an enforcement agent with the following information:
(a)
(b)
(c)
(d)
(e)
discriminatory/non-discriminatory display strategy;
the VIN (vehicle identification number);
presence of a continuous-MI;
the readiness of the OBD system;
the number of engine operating hours during which a continuous-MI was last activated
(continuous-MI counter).
This information shall be read only access (i.e. no clearing).
4.7.1.2. Information about Active Emission-related Malfunctions
This information will provide any inspection station with a subset of engine related OBD
data including the malfunction indicator status and associated data (MI counters), a list of
active/confirmed malfunctions of Classes A and B and associated data (e.g. B1-counter).
The OBD system shall provide all information (according to the applicable standard set in
Module A, Annex 1) for the external inspection test equipment to assimilate the data and
provide an inspector with the following information:
(a)
(b)
(c)
the GTR (and revision) number;
discriminatory/ non-discriminatory display strategy;
the VIN (vehicle identification number);

(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
(p)
the confirmed and active DTCs for Class A malfunctions;
the confirmed and active DTCs for Classes B (B1 and B2) malfunctions;
the cumulated operating hours with a continuous-MI (cumulative continuous-MI
counter);
the value of the B1 counter with the highest number of engine operating hours;
the confirmed and active DTCs for Class B1 malfunctions and the number of engine
operating hours from the B1-counter(s);
the confirmed and active DTCs for Class C malfunctions;
the pending DTCs and their associated class;
the previously active DTCs and their associated class;
real-time information on OEM selected and supported sensor signals, internal and
output signals (see Paragraph 4.7.2. and Annex 5);
(q) the freeze frame data requested by this module (see Paragraph 4.7.1.4. and Annex 5);
(r)
(s)
the software calibration identification(s);
the calibration verification number(s).
The OBD system shall clear all the recorded malfunctions of the engine system and related
data (operating time information, freeze frame, etc.) in accordance with the provisions of this
module, when this request is provided via the external repair test equipment according to the
applicable standard set in Module A Annex 1.
4.7.1.4. Freeze Frame Information
If required by a Contracting Party, the OBD system may provide access to a subset of the
following requirements:
At least one "freeze frame" of information shall be stored at the time that either a potential
DTC or a confirmed and active DTC is stored at the decision of the manufacturer. The
manufacturer is allowed to update the freeze frame information whenever the pending DTC is
detected again.
The freeze frame shall provide the operating conditions of the vehicle at the time of
malfunction detection and the DTC associated with the stored data. The freeze frame shall
include the information as shown in Table 1 in Annex 5 of this module. The freeze frame shall
also include all of the information in Tables 2 and 3 of Annex 5 of this module that are used
for monitoring or control purposes in the specific control unit that stored the DTC.
Storage of freeze frame information associated with a Class A malfunction shall take
precedence over information associated with a Class B1 malfunction which shall take
precedence over information associated with a Class B2 malfunction and likewise for
information associated with a Class C malfunction. The first malfunction detected shall take
precedence over the most recent malfunction unless the most recent malfunction is of a
higher class.

4.7.2. Data Stream Information
If required by a Contracting Party, the OBD system may provide access to a subset of the
following requirements:
The OBD system shall make available to a scan tool in real time the information shown in
Tables 1 to 4 in Annex 5 of this module, upon request (actual signal values should be used in
favour of surrogate values).
For the purpose of the calculated load and torque parameters, the OBD system shall report
the most accurate values that are calculated within the applicable electronic control unit
(e.g. the engine control computer).
Table 1 in Annex 5 gives the list of mandatory OBD information relating to the engine load
and speed.
Table 2 in Annex 5 shows the other OBD information which must be included if used by the
emission or OBD system to enable or disable any OBD monitors .
Table 3 in Annex 5 shows the information which is required to be included if the engine is so
equipped, senses or calculates the information . At the decision of the manufacturer, other
freeze frame or data stream information may be included.
In case a device is monitored by the OBD system and is not covered by Annex 5 (e.g. SCR),
the data-stream information shall include elements of information for the sensors and
actuators of this device in a way similar to those described in Annex 5. This shall be
submitted for approval by the certification authority at the time of certification

Computer-coded engine operating parameters shall not be changeable without the use of
specialised tools and procedures (e.g. soldered or potted computer components or sealed (or
soldered) computer enclosures).
Manufacturers shall take adequate steps to protect the maximum fuel delivery setting from
tampering while a vehicle is in-service.
Manufacturers may apply to the certification authority for an exemption from one of these
requirements for those vehicles that are unlikely to require protection. The criteria that the
certification authority will evaluate in considering an exemption will include, but are not limited
to, the current availability of performance chips, the high-performance capability of the vehicle
and the projected sales volume of the vehicle.
Manufacturers using programmable computer code systems (e.g. electrical erasable
programmable read-only memory, EEPROM) shall deter unauthorised reprogramming.
Manufacturers shall include enhanced tamper-protection strategies and write protect features
requiring electronic access to an off-site computer maintained by the manufacturer.
Alternative methods giving an equivalent level of tamper protection may be approved by the
certification authority.
5. PERFORMANCE REQUIREMENTS
5.1. Thresholds
The OTLs for the applicable monitoring criteria defined in Annex 3 are defined by the
Contracting Party as follows:
(a)
(b)
(c)
(d)
(e)
if the "WHDC" GTR is used for certifying the engine with regard to its exhaust
emissions, the world harmonised OBD test cycle as defined in this module applies and
the relevant regional OTLs shall be applicable accordingly.
if the current UNECE Regulation is used for certifying the engine with regard to its
exhaust emissions, the UNECE Regulation No. 49 OBD test-cycle and the
UNECE Regulation OTLs shall be applicable accordingly.
if the European Union regulation is used for certifying the engine with regard to its
exhaust emissions, the EU OBD test-cycle and the EU OTLs shall be applicable
accordingly.
if the United States of America or California regulation is used for certifying the engine
with regard to its exhaust emissions, the US or California OBD test-cycle and the
United States of America or California OTLs shall be applicable accordingly.
if the Japanese regulation is used for certifying the engine with regard to its exhaust
emissions, the Japanese OBD test-cycle and the Japanese OTLs shall be applicable
accordingly.
5.2. Temporary Disablement of the OBD System
Contracting parties may allow certification authorities to approve that an OBD system be
temporarily disabled under the conditions specified in the following sub-paragraphs.
If so, manufacturers shall obtain approval for temporary disablement strategies by the
certification authority at the time of certification or type approval.

5.2.4. Vehicle Battery or System Voltage Levels
Manufacturers may request approval to disable monitoring systems that can be affected by
vehicle battery or system voltage levels.
5.2.4.1. Low Voltage
For monitoring systems affected by low vehicle battery or system voltages, manufacturers
may request approval to disable monitoring systems when the battery or system voltage is
below 90% of the nominal voltage (or 11.0 Volts for a 12 Volt battery, 22.0 Volts for a 24 volt
battery). Manufacturers may request approval to utilise a voltage threshold higher than this
value to disable system monitoring.
The manufacturer shall demonstrate that monitoring at the voltages would be unreliable and
that either operation of a vehicle below the disablement criteria for extended periods of time is
unlikely or the OBD system monitors the battery or system voltage and will detect a
malfunction at the voltage used to disable other monitors.
5.2.4.2. High Voltage
For emission related monitoring systems affected by high vehicle battery or system voltages,
manufacturers may request approval to disable monitoring systems when the battery or
system voltage exceeds a manufacturer-defined voltage.
The manufacturer shall demonstrate that monitoring above the manufacturer-defined voltage
would be unreliable and that either the electrical charging system/alternator warning light is
illuminated (or voltage gauge is in the "red zone") or the OBD system monitors the battery or
system voltage and will detect a malfunction at the voltage used to disable other monitors.
5.2.5. Active PTO (Power Take-off Units)
The manufacturer may request approval to temporarily disable affected monitoring systems in
vehicles equipped with a PTO unit, under the condition where that PTO unit is temporarily
active.
5.2.6. Forced Regeneration
5.2.7. AECS
The manufacturer may request approval to disable the affected OBD monitoring systems
during the forced regeneration of an emission control system downstream of the engine
(e.g. a particulate filter).
The manufacturer may request approval to disable OBD system monitors during the operation
of an AECS, including MECS, under conditions not already covered in Paragraph 5.2. if the
monitoring capability of a monitor is affected by the operation of an AECS.

The manufacturer may request approval by the certification authority of minor differences in
the methods of monitoring/diagnosing the engine emission control system due to engine
system configuration variation, when these methods are considered similar by the
manufacturer and:
(a)
(b)
they differ only to match specificities of the considered components (e.g. size, exhaust
flow, etc.); or
their similarities are based on good engineering judgement.
6.1.2. OBD-Parent Engine System
Compliance of an emission-OBD family with the requirements of this GTR is achieved by
demonstrating the compliance of the OBD-parent engine system of this family.
The selection of the OBD-parent engine system is made by the manufacturer and subject to
the approval of the certification authority.
Prior to testing the certification authority may decide to request the manufacturer to select an
additional engine for demonstration.
The manufacturer may also propose to the certification authority to test additional engines to
cover the complete emission-OBD family.
6.2. Procedures for Demonstrating the Malfunction Classification
The manufacturer shall provide the documentation justifying the proper classification of each
malfunction to the certification authority. This documentation shall include a failure analysis
(for example elements of a "failure mode and effect analysis") and may also include:
(a)
(b)
(c)
simulation results;
test results;
reference to previously approved classification.
In the following Paragraphs the requirements for demonstrating the correct classification are
listed, including requirements for testing. The maximum and/or minimum number of tests to
be required by the certification authority is defined by each Contracting Party.
In specific cases where the classification testing is not possible (for example, if an MECS is
activated and the engine cannot run the applicable test, etc.), the malfunction may be
classified based on technical justification. This exception shall be documented by the
manufacturer and is subject to the agreement of the certification authority.
6.2.1. Demonstration of Classification into A
The classification by the manufacturer of a malfunction into Class A shall not be subject to a
demonstration test.
If the certification authority disagrees with a manufacturer's classification of a malfunction as
Class A, the certification authority requires the classification of the malfunction into Class B1,
B2 or C, as appropriate.

6.2.6. Demonstration of Classification into C
In order to justify the classification of a malfunction into Class C the manufacturer shall
demonstrate that emissions are lower than the regulated emission limits.
In case the certification authority disagrees with the classification of a malfunction as Class C
the manufacturer may be required to demonstrate by testing that the emissions due to the
malfunction are below the regulated emission limits.
If the test fails, then the certification authority shall request the reclassification of that
malfunction and the manufacturer shall subsequently demonstrate the appropriate
reclassification and the documentation shall be updated.
6.3. Procedures for Demonstrating the OBD Performance
The manufacturer shall submit to the certification authority a complete documentation
package justifying the compliance of the OBD system as regards its monitoring capability,
which may include:
(a)
(b)
(c)
algorithms and decision charts;
tests and/or simulation results;
reference to previously approved monitoring systems, etc.
In the following Paragraphs the requirements for demonstrating the OBD performance are
listed, including requirements for testing. The maximum and/or minimum number of tests to
be required by the certification authority is defined by each Contracting Party.
6.3.1. Procedures for Demonstrating the OBD Performance by Testing
In addition to the supporting data referred to in Paragraph 6.3., the regulation of the
Contracting Party may require the manufacturer to demonstrate the proper monitoring of
specific emission control systems or components by testing them on an engine test-bed
according to the test procedures specified in Paragraph 7.2. of this module.
In that case, the manufacturer shall make available the qualified deteriorated components or
the electrical device which would be used to simulate a malfunction.
The proper detection of the malfunction by the OBD system and its proper response to that
detection (see MI indication, DTC storage, etc.) shall be demonstrated according to
Paragraph 7.2.

6.4. Certification of an OBD System Containing Deficiencies
6.4.1. Contracting parties may allow certification authorities to approve upon request of a
manufacturer an OBD system even though the system contains one or more deficiencies.
In considering the request, the certification authority shall determine whether compliance with
the requirements of this module is feasible or unreasonable.
The certification authority shall take into consideration data from the manufacturer that details
such factors as, but not limited to, technical feasibility, lead time and production cycles
including phase-in or phase-out of engines designs and programmed upgrades of computers,
the extend to which the resultant OBD system will be effective in complying with the
requirements of this GTR and that the manufacturer has demonstrated an acceptable level of
effort toward meeting the requirements of the GTR.
The certification authority will not accept any deficiency request that includes the complete
lack of a required diagnostic monitor (i.e. a complete lack of the monitors required in the
appendices to Annex 3).
A Contracting Party may prohibit a certification authority from approving a deficiency where
that deficiency would result in the OTLs being exceeded.
6.4.2. Deficiency Period
A deficiency is granted for a period of one year after the date of certification of the engine
system.
If the manufacturer can adequately demonstrate to the certification authority that substantial
engine modifications and additional lead time would be necessary to correct the deficiency,
then this deficiency can be granted again for an additional one year, provided that the total
deficiency period does not exceed 3 years (i.e. 3 times one year deficiency allowance is
permitted).
The manufacturer cannot apply for a renewal of the deficiency period.
6.5. Direct Certification of the Installation of an OBD System on a Heavy-duty Vehicle
If a Contracting Party requires or permits the direct certification of the installation of an OBD
system on a vehicle, the requirements set in Annex 1 apply.

7.1.2. Testing Process for Demonstrating the OBD Performance
When the certification authority requests according to Paragraph 6.3. to test the OBD system
performance, the compliance demonstration shall consist of the following phases:
(a)
(b)
(c)
a malfunction is selected by the certification authority and a corresponding deteriorated
component or system shall be made available by the manufacturer;
when appropriate and if requested, the manufacturer shall demonstrate by an emission
test that the deteriorated component is qualified for a monitoring demonstration;
the manufacturer shall demonstrate that the OBD system responds in a manner that
complies with the provisions of this GTR (i.e. MI indication, DTC storage, etc.) at the
latest by the end of a series of OBD test-cycles.
7.1.2.1. Qualification of the Deteriorated Component
When the certification authority requests the manufacturer to qualify a deteriorated
component by testing according to Paragraph 6.3.2., this demonstration shall be made by
performing an emissions test.
If it is determined that the installation of a deteriorated component or device on an engine
system means that a comparison with the OBD threshold limits is not possible (e.g. because
the statistical conditions for validating the applicable emission test cycle are not met), the
malfunction of that component or device may be considered as qualified upon the agreement
of the certification authority based on technical rationale provided by the manufacturer.
In the case that the installation of a deteriorated component or device on an engine means
that the full load curve (as determined with a correctly operating engine) cannot be attained
during the test, the deteriorated component or device may be considered as qualified upon
the agreement of the certification authority based on technical rationale provided by the
manufacturer.
7.1.2.2. Malfunction Detection
Each monitor selected by the certification authority to be tested on an engine test-bed, shall
respond to the introduction of a qualified deteriorated component in a manner that meets the
requirements of this GTR within two consecutive OBD test-cycles according to Paragraph
7.2.2. of this module.
When it has been specified in the monitoring description and agreed by the certification
authority that a specific monitor needs more than two operating sequences to complete its
monitoring, the number of OBD test-cycles may be increased according to the manufacturer's
request.
Each individual OBD test-cycle in the demonstration test shall be separated by an engine
shut-off. The time until the next start-up shall take into consideration any monitoring that may
occur after engine shut-off and any necessary condition that must exist for monitoring to occur
at the next start up.
The test is considered complete as soon as the OBD system has responded in a manner that
meets the requirements of this GTR.

7.2.3. Test Operating Conditions
The conditions (i.e. temperature, altitude, fuel quality etc.) for conducting the tests referred to
in Paragraphs 7.2.1. and 7.2.2. shall be those required for operating the WHDC procedure in
the "WHDC" GTR No. 4.
If a Contracting Party decides to implement this GTR and the "WHDC" GTR is not
implemented by this Contracting Party, the conditions for conducting the tests referred to in
Paragraphs 7.2.1. and 7.2.2. are the conditions required for operating the applicable
regionally accepted emission test-cycle.
In the case of an emission test aimed at justifying the classification of a specific malfunction
into Class B1, the test operating conditions may, per decision of the manufacturer, deviate
from the ones in the Paragraphs above according to Paragraph 6.2.2.
7.3. Test Reports
If a test report is required by a Contracting Party for certification purposes, that report shall
contain, at a minimum, the information set out in Annex 4.
8. DOCUMENTATION REQUIREMENTS
8.1. Documentation for Purpose of Certification
The manufacturer shall provide a documentation package that includes a full description of
the OBD system. The documentation package shall be made available in two parts:
(a)
(b)
a first part, which may be brief, provided that it exhibits evidence concerning the
relationships between monitors, sensors/actuators, and operating conditions
(i.e. describes all enable conditions for monitors to run and disable conditions that
cause monitors not to run). The documentation shall describe the functional operation
of the OBD, including the malfunction ranking within the hierarchical classification. This
material shall be retained by the certification authority. This information may be made
available to interested parties upon request.
a second part containing any data, including details of qualified deteriorated
components or systems and associated test results, which are used as evidence to
support the decision process referred to above, and a listing of all input and output
signals that are available to the engine system and monitored by the OBD system. This
second part shall also outline each monitoring strategy and the decision process.
This second part shall remain strictly confidential. Upon decision of the contracting party
implementing this GTR, it may be kept by the certification authority, or, at the discretion of the
certification authority, may be retained by the manufacturer but shall be made open for
inspection by the certification authority at the time of certification or at any time during the
validity of the certification.

8.2. Documentation for Installing in a Vehicle an OBD Equipped Engine System
The engine manufacturer shall include in the installation documents of its engine system the
appropriate requirements that will ensure the vehicle, when used on the road or elsewhere as
appropriate, will comply with the requirements of this GTR. This documentation shall include
but is not limited to:
(a)
(b)
the detailed technical requirements, including the provisions ensuring the compatibility
with the OBD system of the engine system;
the verification procedure to be completed.
The existence and the adequacy of such installation requirements may be checked during the
certification process of the engine system.
9. ANNEXES
Note: In the case a vehicle manufacturer applies for a direct certification of the installation of
the OBD system on the vehicle, this documentation is not required.
ANNEX 1:
ANNEX 2:
ANNEX 3:
ANNEX 4:
ANNEX 5:
Certification of installation of OBD systems
Malfunctions − Illustration of the DTC status − illustration of the MI and counters
activation schemes
Monitoring Requirements
Technical compliance report
Freeze frame and data stream information

MODULE B − ANNEX 2
MALFUNCTIONS ILLUSTRATION OF THE DTC STATUS
ILLUSTRATION OF THE MI AND COUNTERS ACTIVATION SCHEMES
This Annex aims at illustrating the requirements set in Paragraphs 4.3. and 4.6.5. of this module.
It contains the following figures:
Figure 1:
Figure 2
Figure 3:
Figure 4:
Figure 5:
DTC status in case of a Class B1 malfunction
DTC status in case of 2 consecutive different Class B1 malfunctions
DTC status in case of the re-occurrence of a Class B1 malfunction
Class A malfunction − activation of the MI and MI counters
Class B1 malfunction − activation of the B1 counter in 5 use cases
Figure 1
DTC Status in Case of a Class B1 Malfunction
Notes:
� Means the point a monitoring of the concerned malfunction occurs
N, M The GTR requires the identification of "key" operating sequences during which some events
occurs, and the counting of the subsequent operating sequences. For the purpose of
illustrating this requirement, the "key" operating sequences have been given the values N and
M.
E.g. M means the first operating sequence following the detection of a potential malfunction,
and N means the operating sequence during which the MI is switched OFF.
N + 40 the fortieth operating sequence after deactivation of the MI or 200 engine operating hours,
whichever the earliest.

Figure 3
DTC Status in Case of the Re-occurrence of a Class B1 Malfunction
Notes:

N, M,
N', M'
Means the point a monitoring of the concerned malfunction occurs.
The GTR requires the identification of "key" operating sequences during which some events
occurs, and the counting of the subsequent operating sequences.
For the purpose of illustrating this requirement, the "key" operating sequences have been given
the values N and M for the first occurrence of a malfunction, respectively N' and M' for the
second one.
E.g. M means the first operating sequence following the detection of a potential malfunction,
and N means the operating sequence during which the MI is switched OFF.

Figure 4bis
Illustration of the Continuous MI Deactivation Principle
Notes:

M
Case 1
Case 2
Case 3
means the point where monitoring of the concerned malfunction occurs.
means the operating sequence when the monitor concludes for the first time that a confirmed
and active failure is no longer present.
means the case where the monitor does not conclude the presence of failure during the
operating sequence M.
means the case where the monitor has previously concluded, during the operating
sequence M, the presence of the malfunction.
means the case where the monitor concludes, during the operating sequence M, the
presence of the malfunction after having first concluded to its absence.

MODULE B − ANNEX 3
MONITORING REQUIREMENTS
The appendices of this Annex list the systems or components required to be monitored by the OBD
system, according to Paragraph 4.2.
These appendices separate the basic monitoring requirements from the enhanced monitoring
requirements that may be introduced, some or all, into a regional regulation by a Contracting Party at the
time of introduction of that regulation, according to Paragraph 4.2.

MODULE B − ANNEX 3 − APPENDIX 2
DPF SYSTEM
The OBD system shall monitor the following elements of the DPF system on engines so-equipped for
proper operation:
(a)
(b)
(c)
DPF substrate: the presence of the DPF substrate − total functional failure monitoring
DPF performance: clogging of the DPF − total functional failure
DPF performance: filtering and regeneration processes (e.g. particulate accumulation during the
filtering process and particulate removal during a forced regeneration process) − performance
monitoring (for example, evaluation of measurable DPF properties such as backpressure or
differential pressure, which may not detect all failure modes that reduce trapping efficiency).
The following enhanced monitoring requirements may also be introduced into regional regulation, where
determined to be technically feasible by a Contracting Party at the time of introduction of that regulation:
(a)
(b)
(c)
(d)
(e)
DPF filtering performance: the filtering and continuous regeneration process of the DPF. This
requirement would apply to PM emissions only − emission threshold monitoring.
DPF forced regeneration excessive frequency: the frequency of forced regeneration events
(i.e. those regeneration events that are initiated via a driver selectable switch or activator and/or
those initiated by computer software). This requirement would apply to HC emissions −
performance monitoring.
DPF incomplete forced regeneration: forced regeneration events for completeness under
manufacturer-defined conditions where regeneration is designed to occur − performance
monitoring
DPF HC conversion efficiency: the ability of the catalysed DPF to convert HC as required for
compliance with emissions limits. - emission threshold monitoring.
DPF active/intrusive reductant injection system: the system's ability to regulate reductant delivery
properly, whether delivered via an in-exhaust injection or an in-cylinder injection − component
monitoring.

MODULE B − ANNEX 3 − APPENDIX 4
LEAN- NO TRAP (LNT, OR NO ADSORBER)
The OBD system shall monitor the following elements of the LNT system on engines so-equipped for
proper operation:
(a)
(b)
LNT capability: the LNT system's ability to adsorb/store and convert NO − performance
monitoring.
LNT active/intrusive reductant injection system: the system's ability to regulate reductant delivery
properly, whether delivered via an in-exhaust injection or an in-cylinder injection − performance
monitoring.
The following enhanced monitoring requirements may also be introduced into regional regulation, where
determined to be technically feasible by a Contracting Party at the time of introduction of that regulation:
LNT capability: the LNT system's ability to adsorb/store and convert NO - emission threshold monitoring.

MODULE B − ANNEX 3 − APPENDIX 6
EXHAUST GAS RECIRCULATION (EGR) SYSTEM MONITORING
The OBD system shall monitor the following elements of the EGR system on engines so-equipped for
proper operation:
(a)
(b)
(c)
EGR low/high flow: the EGR system's ability to maintain the commanded EGR flow rate, detecting
both "flow rate too low" and "flow rate too high" conditions − emission threshold monitoring.
EGR actuator: the EGR system's ability to achieve the commanded flow rate within a manufacturer
specified time interval following the command − performance monitoring.
EGR cooler undercooling performance: the EGR cooler system's ability to achieve the
manufacturer's specified cooling performance − performance monitoring.
The following enhanced monitoring requirements may also be introduced into regional regulation, where
determined to be technically feasible by a Contracting Party at the time of introduction of that regulation:
(a)
(b)
slow response of the EGR actuator: the EGR system's ability to achieve the commanded flow rate
within a manufacturer specified time interval following the command − emission threshold
monitoring.
EGR cooler performance: the EGR cooler system's ability to achieve the manufacturer's specified
cooling performance − emission threshold monitoring.
(c) EGR low flow : the EGR system's ability to maintain the commanded EGR flow rate, detecting
"flow rate too low" conditions – total functional failure or performance monitoring .
(d) EGR cooler undercooling performance : the EGR cooler system's ability to achieve the
manufacturer's specified cooling performance – total functional failure monitoring.

MODULE B − ANNEX 3 − APPENDIX 8
AIR HANDLING AND TURBOCHARGER/BOOST PRESSURE CONTROL SYSTEM
The OBD system shall monitor the following elements of the air handling and turbocharger/boost
pressure control system on engines so-equipped for proper operation:
(a)
(b)
(c)
Turbo under/over boost: turbo boost system's ability to maintain the commanded boost pressure,
detecting both "boost pressure too low" and "boost pressure too high" conditions − emission
threshold monitoring.
Variable Geometry Turbo (VGT) slow response: VGT system's ability to achieve the commanded
geometry within a manufacturer specified time − performance monitoring.
Charge air cooling: Charge air cooling system efficiency - total functional failure.
The following enhanced monitoring requirements may also be introduced into regional regulation, where
determined to be technically feasible by a Contracting Party at the time of introduction of that regulation:
(a)
(b)
(c)
Variable Geometry Turbo (VGT) slow response: VGT system's ability to achieve the commanded
geometry within a manufacturer specified time − emission threshold monitoring.
Charge air heating: Charge air heating ability to be used as part of a cold engine starting strategy
against manufacturer specified limits − performance monitoring.
Charge air cooling: Charge air cooling system efficiency − emission threshold monitoring.
(d) Turbo under boost : turbo boost system's ability to maintain the commanded boost pressure,
detecting "boost pressure too low" conditions – total functional failure or performance monitoring .

MODULE B − ANNEX 3 − APPENDIX 10
MISFIRE MONITORING
The following enhanced monitoring requirements may also be introduced into regional regulation, where
determined to be technically feasible by a Contracting Party at the time of introduction of that regulation:
(a)
For engines not equipped with combustion sensors:
Continuous misfiring: misfire conditions occurring continuously in a cylinder. If more than one
cylinder is misfiring continuously, then this must also be detected. The specific cylinder(s) that are
misfiring need not be identified − total functional failure.
(b)
For engines equipped with combustion sensors:
Cylinder misfiring: misfire conditions in one cylinder or more - emission threshold monitoring.

MODULE B − ANNEX 3 − APPENDIX 12
ENGINE COOLING SYSTEM MONITORING
The OBD system shall monitor the following elements of the engine cooling system for proper operation:
(a)
Engine coolant temperature (thermostat): Stuck open thermostat. Manufacturers need not
monitor the thermostat if its failure will not disable any other OBD monitors − total functional
failure.
The following enhanced monitoring requirements may also be introduced into regional regulation, where
determined to be technically feasible by a Contracting Party at the time of introduction of that regulation:
(a)
(b)
Engine coolant temperature (thermostat): ability to reach the highest temperature required in the
manufacturer specified conditions (e.g. time, etc.) to enable any other emission-related OBD
monitors. Manufacturers need not monitor the thermostat if its failure will not disable any other
OBD monitors − performance monitor.
Engine coolant temperature sensor (or equivalent): measurement ability for detecting the stabilised
minimum temperature that is needed to initiate closed-loop/feedback control of all affected
emission control systems (e.g. fuel system, EGR system) − performance monitor.
Manufacturers need not monitor the engine coolant temperature or the engine coolant temperature
sensor if the engine coolant temperature or the engine coolant temperature sensor is not used to enable
closed-loop/feedback control of any emissions control systems and/or will not disable any other monitor.
Manufacturers may suspend or delay the monitor for the time to reach close loop enable temperature if
the engine is subjected to conditions that could lead to false diagnosis (e.g. vehicle operation at idle for
more than 50% to 75% of the warm-up time).

MODULE B − ANNEX 3 − APPENDIX 14
IDLE SPEED CONTROL SYSTEM MONITORING
The OBD system shall monitor the electrical elements of the idle speed control systems on engines
so-equipped for proper operation according to Appendix 1 to this Annex.
The following enhanced monitoring requirements for monitoring idle speed control systems may be
introduced into regional regulation, where determined to be technically feasible by a Contracting Party at
the time of introduction of that regulation:
(a)
(b)
idle fuel control system: the idle fuel control system ability to achieve the target idle speed or fuel
injection quantity within +/-50% of the manufacturer-specified fuel quantity and engine speed
tolerances − performance monitoring
idle fuel control system: the idle fuel control system ability to achieve the target idle speed or
fuelling quantity within an engine speed or fuelling quantity tolerance range required by the OBD
system to enable any other OBD monitors − performance monitoring.

MODULE B − ANNEX 4 − APPENDIX 1 TO THE TECHNICAL COMPLIANCE REPORT (EXAMPLE)
1. Type of requested certification
INFORMATION CONCERNING THE OBD SYSTEM
Requested Certification
− Certification of an individual OBD system
− Certification of an emission OBD family
− Certification of an OBD system as member of a certified emission OBD family
− Extension to include a new engine system into an emission OBD family
− Extension to address a design change that affects the OBD system
− Extension to address a malfunction reclassification
YES/NO
YES/NO
YES/NO
YES/NO
YES/NO
YES/NO
2. Information concerning the OBD system
Certification of an individual OBD system
− type(s) of the engine system family (where applicable, see Paragraph 6.1.),
or type(s) of the single engine system(s)
− OBD description (issued by the manufacturer): reference and date
Certification of an emission OBD family
− List of the engine families concerned by the emission OBD family (when
applicable, see Paragraph 6.1.)
− Type of the parent engine system within the emission OBD family
− List of the engine types within the emission OBD family
− OBD description (issued by the manufacturer): reference and date
Certification of an OBD system as member of a certified emission OBD family
− List of the engine families concerned by the emission OBD family (when
applicable, see Paragraph 6.1.)
− Type of the parent engine system within the emission OBD family
− List of the engine types within the emission OBD family
− Name of the engine system family concerned by the new OBD system (when
applicable)
− Type of the engine system concerned by the new OBD system
− Extended OBD description (issued by the manufacturer): reference and date
Extension to include a new engine system into an emission OBD family

List (extended if necessary) of the engine families concerned by the emission
OBD family (when applicable, see Paragraph 6.1.)

List (extended if necessary) of the engine types
within the emission OBD
family

Actualised (new or unchanged) type
of the parent engine system within the
emission OBD family

Extended OBD description (issued by the manufacturer): reference and date
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .

MODULE B − ANNEX 4 − APPENDIX 2 TO THE TECHNICAL COMPLIANCE REPORT (EXAMPLE)
INFORMATION CONCERNING THE CONFORMITY OF THE OBD SYSTEM
1. Documentation package
The elements provided by the manufacturer in the documentation package of
the emission OBD family, is complete and complies with the requirements of
Paragraph 8. of Module B of this GTR, on the following issues:
− documentation associated with each monitored component or system
− documentation associated with each DTC
− documentation associated with the malfunction classification
− documentation associated with the emission OBD family
YES/NO
YES/NO
YES/NO
YES/NO
The documentation required in Paragraph 8.2. of this GTR for installing an
OBD system in a vehicle has been provided by the manufacturer in the
documentation package, is complete, and complies with the requirements of
this GTR: YES/NO
The installation of the engine system equipped with the OBD system complies
with Annex 1 of this GTR:
Note: this statement applies only in the case the engine manufacturer has not
provided the documentation required in Paragraph 8.2., or if compliance of the
installation is required by the Contracting Party:
YES/NO/
Not
applicable
2. Content of the documentation
Monitoring
The monitors comply with the requirements of Paragraph 4.2. of Module
B of this GTR: YES/NO
Classification
The malfunction classification complies with the requirements of
Paragraph 4.5. of Module B of this GTR: YES/NO
MI activation scheme
According to Paragraph 4.6.3. of this GTR, the MI-activation scheme is:
The activation and the extinguishing of the malfunction indicator comply
with the requirements of Paragraph 4.6. of Module B of this GTR:
Discriminatory/
Non-discriminatory
YES/NO
DTCs recording & erasing
The recording and erasing of DTCs comply with the requirements of
Paragraphs 4.3. and 4.4. of Module B of this GTR: YES/NO
Disablement of the OBD system
The strategies described in the documentation package for a momentary
disconnection or disablement of the OBD system comply with the
requirements of Paragraph 5.2. of this GTR: YES/NO
Electronic system security
The measures described by the manufacturer for electronic system
security comply with the requirements of Paragraph 4.8. of this GTR: YES/NO

MODULE B − ANNEX 4 − APPENDIX 4 TO THE TECHNICAL COMPLIANCE REPORT (EXAMPLE)
1. Test result of the OBD system
DEMONSTRATION TESTS OF THE OBD SYSTEM
Results of the tests
The OBD system described in the above complying documentation package
has been tested with success according to Paragraph 6. of this GTR for
demonstrating the compliance of monitors and of malfunction classifications
as listed in Appendix 5 YES/NO
Details to the conducted demonstration tests are given in Appendix 5.
1.1. OBD system tested on the engine test-bed
Engine
− Engine name (manufacturer and commercial names):
− Engine type (as reported in the certification document):
− Engine number (serial number):
Control units concerned by this GTR (incl. engine ECUs)
− Main functionality
− Identification number (software and calibration):
Diagnostic tool (scan tool used during testing)
− Manufacturer:
− Type:
− Software / version
Test information
− Ambient testing conditions (temperature, humidity, pressure):
− Place of test (incl. altitude):
− Testing fuel:
− Engine lubricating oil:
− Date of test:
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .

APPENDIX 5 TO THE TECHNICAL COMPLIANCE REPORT (EXAMPLE)
TEST PROTOCOL

Table 3
Other Information
(if the engine is so equipped, senses or calculates the information)
Freeze frame Data stream
Absolute throttle position/intake air throttle position (position of valve used to
regulate intake air)
x
x
Diesel fuel control system status in case of a close loop system (e.g. in case
of a fuel pressure close loop system)
x
x
Fuel rail pressure x x
Injection control pressure (i.e. pressure of the fluid controlling fuel injection) x
Representative fuel injection timing (beginning of first main injection) x x
commanded fuel rail pressure, x x
Commanded injection control pressure (i.e. pressure of the fluid controlling
fuel injection)
x
x
Intake air temperature x x
ambient air temperature x x
Turbocharger inlet/outlet air temperature (compressor and turbine) x x
turbocharger inlet/outlet pressure(compressor and turbine) x x
Charge air temperature (post intercooler if fitted) x x
Actual boost pressure x x
Air flow rate from mass air flow sensor x x
Commanded EGR valve duty cycle/position, (provided EGR is so controlled) x
Actual EGR valve duty cycle/position x x
PTO status (active or not active) x x
Accelerator pedal position x x
Redundant absolute pedal position x if sensed
Instantaneous fuel consumption x x
Commanded/target boost pressure (if boost pressure used to control turbo
operation)
DPF inlet pressure x x
DPF outlet pressure x x
DPF delta pressure x x
Engine-out exhaust pressure x x
x
x
x
x

OBD Systems for Road Vehicles.