Global Technical Regulation No. 18

Name:Global Technical Regulation No. 18
Description:On-board Diagnostics - Two or Three Wheeled Motor Vehicles.
Official Title:Global Technical Regulation on the Measurement Procedure for Two or Three Wheeled Motor Vehicles with Regard to On-board Diagnostics.
Country:ECE - United Nations
Date of Issue:2017-03-08
Amendment Level:Original
Number of Pages:42
Vehicle Types:Motorcycle
Subject Categories:Electrical and Electronic, Emissions and Fuel Consumption
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Keywords:

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Text Extract:

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ECE/TRANS/180/Add.18
March 8, 2017
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 18:
GLOBAL TECHNICAL REGULATION NO. 18
GLOBAL TECHNICAL REGULATION ON THE MEASUREMENT PROCEDURE
FOR TWO- OR THREE-WHEELED MOTOR VEHICLES WITH REGARD TO
ON-BOARD DIAGNOSTICS
(ESTABLISHED IN THE GLOBAL REGISTRY ON NOVEMBER 17, 2016)

GLOBAL TECHNICAL REGULATION NO. 18
I. STATEMENT OF TECHNICAL RATIONALE AND JUSTIFICATION
A. INTRODUCTION
1. The industry producing two- and three-wheeled vehicles in the scope of this Global
Technical Regulation (GTR) is a global one, with companies selling their products in many
different countries. The Contracting Parties to the 1998 Agreement have determined that
work should be undertaken to address the environmental and propulsion unit performance
requirements of two- and three-wheeled light motor vehicles, among others as a way to help
improve air quality internationally. Currently, the GTR is directed at harmonizing On-Board
Diagnostic requirements (OBD) for two- and three-wheeled vehicles, similar as targeted with
GTR No. 5 for heavy duty vehicles. This common set of agreed rules in the area of OBD
allows the Contracting Parties to realize their own domestic objectives and to pursue their
own levels of priorities. 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
and objectives in the future.
2. This GTR establishes harmonized functional requirements for OBD and a procedure to test
and verify the environmental OBD functions (Test Type VIII). The functional requirements
and test procedures were developed so that they would be:
(a)
Able to provide an internationally harmonized set of functional OBD requirements with
respect to the "infra-structure" on-board of a vehicle in the scope of this GTR, which
determines hardware and software design in a technology neutral way and that
considers technical feasibility and cost-effectiveness, such as:
(i)
(ii)
(iii)
Minimum monitoring requirements of electric and electronic circuits and failure
mode detection as well as for monitoring of the control module(s) within the
scope of OBD Stage I set out in Table 2 of Annex 2;
Provisions regarding diagnostic trouble codes, diagnostic signals and
connection interfaces;
Provisions regarding access to OBD information which is needed as input to
the repair process of a broken vehicles.
(b)
(c)
(d)
(e)
(f)
Allowing referencing of international technical standards already established for other
vehicle types with a proven track record of providing clarity for the design and
configuration of the OBD system;
Able to provide an internationally harmonized set of tests to ensure efficient and
practicable testing;
Corresponding to state of the art testing technology, allowing to simulate failures
where technically feasible;
Applicable in practice to existing and foreseeable future powertrain technologies;
Definition of propulsion unit families with regards to OBD.

C. EXISTING REGULATIONS, DIRECTIVES AND INTERNATIONAL VOLUNTARY STANDARDS
1. Technical References in the Development of the GTR
11. For the development of the GTR, the following legislation and technical standards contain
relevant applications of requirements for motorcycles and other vehicles in the scope of this
GTR or transferable provisions for passenger cars:
(a) UN (1958 Agreement, light-duty legislation): Chapter 11 of Regulation No. 83;
(b) UN (1998 Agreement, heavy-duty legislation): GTR No. 5;
(c)
(d)
UN Mutual Resolution No. 2 (M.R.2);
EU: Annex XII to Regulation (EU) No. 44/2014 (Delegated Act on Vehicle
Construction Requirements supplementing Regulation (EU) No. 168/2013) with
respect to functional OBD requirements, Annex VIII of Regulation (EU) No. 134/2014
(Delegated Act on Environmental and Propulsion Unit Performance supplementing
Regulation (EU) No. 168/2013) and Article 21 of Regulation (EU) No. 168/2013;
(e) Japan: Safety Regulations for Road Vehicles, Article 31, Attachment 115;
(f) The United States of America (light-duty legislation): US CFR, Title 40, Part 86,
Subpart S;
(g)
Standards:
(i) International: ISO 2575, ISO 9141-2, ISO 14229-3, ISO 14229-4, ISO 14230-4,
ISO 15031-4, ISO 15031-5, ISO 15031-6, ISO 15765-4, ISO 20828,
ISO 22901-2;
(ii) USA: SAE J1850.
2. Methodology for Deriving Harmonized Test Procedures for the GTR
12. The European Commission launched an EPPR study for L-Category vehicles in
January 2012 with the objective to develop proposals to update GTR No. 2 for technical
progress and to develop proposals for GTRs and Regulations with respect to harmonized
EPPR legislation not yet covered at the international level for two- and three-wheeled
vehicles, e.g. crankcase and evaporative emission test requirements, on-board diagnostic
requirements, propulsion unit performance requirements, etc. The output of this
comprehensive study was submitted for the review and comments of the EPPR IWG with
the objective to identify concerns and to provide base proposals ready for further
enhancements by the EPPR IWG in order to accommodate the needs at the international
level to assess a vehicle with respect to on-board diagnostics in a scientifically based,
objective and globally accepted way.
13. The outcome of this work was among others the development of a first draft GTR proposal
on OBD based on the consolidation of existing global legislation and up to date technical
provisions. After discussions and adopting a number of amendments the EPPR IWG
decided to take the EC proposal as a basis for the first draft GTR of the Group. This text
then further evolved in many different revisions and was modified in iterative steps to reflect
the discussions and decisions by the Group over the period 2013 - 2016.

Figure 1
Flowchart MI Trigger Activation Criteria
(c)
(d)
Need for a review clause for Table 2 in Annex 2 to update the list for technical
progress in due course;
The effect of OBD Stage I on propulsion unit hard- and software design. The EPPR
IWG decided that OBD Stage I should not oblige manufacturers to change or add
fuelling or ignition hardware and should not impose fitting of an electronic carburettor,
electronic fuel injection or electronically controlled ignition coils, providing the vehicle
complies with the applicable environmental performance requirements.

4. Definitions
21. The definitions used in the GTR are aligned as much as possible with definitions in
international legislation and from the work of the Vehicle Propulsion System Definitions
(VPSD) Group operating under GRPE with the goal to harmonize high level powertrain
definitions as well as from other regional legislation as listed in Chapter C.1. The definitions
set out in Mutual Resolution No. 2 were re-used where possible in this GTR.
22. In the definition of "useful life" a reference to a period of time has been included as
proposed by Japan, because of the following reasons:
(a)
(b)
Firstly, the general life cycle for industrial products is prescribed by its life period, so
the time is the necessary parameter to define the life cycle. For instance, if a vehicle
with the product warranty for "ten years and total mileage of one-hundred-thousand
kilometres" has only one kilometre as total mileage but is 20-years old, the vehicle
should not be regarded as in-warranty.
Secondly, the definition in the GTR on crankcase and evaporative emissions is also
referring to the period of distance and time.
5. Requirements
23. Regarding functional requirements for OBD, the GTR contains the following main items:
(a) Minimum monitoring requirements for OBD Stage I;
(b)
(c)
(d)
Provisions regarding design of the Malfunction Indicator (MI), diagnostic trouble
codes, diagnostic signals and connection interfaces;
Provisions regarding access to OBD information;
Definition of propulsion unit families with regard to OBD.
24. Regarding the environmental test procedure for OBD, the GTR contains the elements:
(a)
(b)
Test vehicle requirements;
Test procedure by simulating failure of exhaust emission relevant components in the
powertrain management system and emission control system and monitoring the
OBD system reaction during a Type I test cycle;
(c) Failure modes to be tested for OBD Stage I.
25. Minimum administrative requirements have been set out to reflect the technical
requirements addressed in this GTR.

II.
TEXT OF THE GLOBAL TECHNICAL REGULATION
1. PURPOSE
1.1. This GTR prescribes the requirements for On-Board Diagnostic (OBD) systems to
detect, and, if applicable, record and/or communicate failures of specific vehicle and
engine systems that affect the environmental performance of these systems, as
described in the specific Annexes to this GTR.
1.2. In addition, this GTR specifies the elements concerning the OBD system to facilitate
the diagnosis, efficient and effective repair and maintenance of specific vehicle and
engine systems without containing mandatory prescriptions for this purpose.
1.3. OBD Stage I should not oblige manufacturers to change or add fuelling or ignition
hardware and should not impose fitting of an electronic carburettor, electronic fuel
injection or electronically controlled ignition coils, providing the vehicle complies with
the applicable environmental performance requirements. Compliance with the OBD
Stage I requirements implies that if fuel delivery, spark delivery or intake air
hardware is electronically controlled, the applicable input or output circuits need to
be monitored, limited to the items and failure modes listed in Table 2 of Annex 2.
1.4. The Malfunction Indicator (MI) design will be harmonized in OBD Stage I but the MI
activation performance criteria are prescribed as two alternative Grades A or B set
out in Table 1 of Annex 2. Consequently, each Contracting Party is free to choose
from these alternatives. In addition, a Contracting Party may opt for the elements
attributed to enhanced diagnostics (Grade C) set out in Table 1 of Annex 2.

3. DEFINITIONS
The definitions set out in GTR No. 2 shall apply. In addition, the following definitions
shall apply in this GTR:
3.1. "Access to OBD" means the unrestricted availability of the on-board diagnostic
information laid down in this GTR via the serial interface for the standard diagnostic
connection, pursuant to Paragraph 3.12. of Annex 1;
3.2. "Calculated load value" refers to an indication of the current airflow divided by
peak airflow, where peak airflow is corrected for altitude, if available. This
definition provides a dimensionless number that is not engine‐specific and provides
the service technician with an indication of the proportion of engine capacity being
used (with wide open throttle as 100%);
3.3. "Calibration" of the powertrain/engine or drive train control unit means the
application specific set of data maps and parameters used by the control unit's
software to tune the vehicle's powertrain/engine or drive train;
3.4. "Communication protocol" means a system of digital message formats and rules
for exchanging those messages in or between computing systems or units;
3.5. "Control system" means the electronic engine management controller and any
component referred to in this GTR which supplies an input to or receives an output
from this controller;
3.6. "Default mode" refers to a case where the engine management controller switches
to a setting that does not require an input from a failed component or system;
3.7. "Deficiency" in respect of vehicle OBD systems, means a situation in which up to
two separate components or systems that are monitored contain temporary or
permanent operating characteristics that impair their otherwise efficient OBD
monitoring or do not meet all other detailed requirements for OBD;
3.8. "Driving cycle" means a Test Type I cycle consisting of engine start-up, driving
mode where a malfunction would be detected if present, and engine shut-off;
3.9. "Limp-home" means an operation mode triggered by the control system that
restricts fuel quantity, intake air quantity, spark delivery or other powertrain control
variables resulting in significant reduction of output torque or engine revolution or
vehicle speed;
3.10. "Malfunction Indicator (MI)" means a visible indicator that clearly informs the
driver of the vehicle in the event of malfunctions;
3.11. "Malfunction" means the failure of an electric /electronic circuit referred to in this
GTR;
3.12. "On-Board Diagnostic system (OBD)" means an electronic system fitted on-board
of a vehicle that has the capability of identifying the likely area of malfunction by
means of fault codes stored in a computer memory which can be accessed by
means of a generic scan tool;

4. List of Acronyms and Symbols
Table 2
List of Acronyms and Symbols
Item Unit Term
APS – accelerator (pedal/handle) position sensor
CAN – controller area network
CARB – California air resources board
CI – compression ignition engine
CO g/km carbon dioxide
DTC
diagnostic trouble code
E85 – ethanol blended petrol, up to 85% Ethanol
ECU – engine control unit
EPA – environmental protection agency, at USA federal level
ETC – electronic throttle control
HCNG – hydrogen-compressed natural gas mixtures
ID – identifier
ISO – international standardisation organisation
LPG – liquefied petroleum gas
MI – malfunction indicator
NG – natural gas
ODX – open diagnostic data exchange
PCU – powertrain control unit
PI – positive ignition engine
PID – parameter identifier
SAE

society of automotive engineers, USA based globally active
standardisation organisation
Test Type I – test of tailpipe emissions after cold start
Test Type V

test of durability of the vehicle's pollution control devices, mix
of distance accumulation and Test Type I verification testing
Test Type VIII

special Test Type I with induced fault mode to assess the
impact on the tailpipe emission performance of a vehicle
TPS – throttle (accelerator actuator) position sensor
UDS – unified diagnostic services
VIN – vehicle identification number

5.2.4.2.1.3. The manufacturer may temporarily disable the OBD system in the following
conditions:
(a)
(b)
(c)
For flex-fuel or mono/bi-fuel gas vehicles for one minute after re-fuelling to
allow for the recognition of fuel quality and composition by the Powertrain
Control Unit(s) (PCU);
For bi-fuel vehicles for five seconds after fuel switching to allow for engine
parameters to be readjusted;
The manufacturer may deviate from these time limits if it can be
demonstrated that stabilisation of the fuelling system after re-fuelling or fuel
switching takes longer for justified technical reasons. In any case, the OBD
system shall be re-enabled as soon as either the fuel quality or composition is
recognised or the engine parameters are readjusted.
5.2.4.3. The OBD system shall monitor for:
5.2.4.3.1. At a minimum the electric/electronic circuits required in Annex.2.
5.2.4.3.2. If active on the selected fuel, other emission control system components or systems, or
emission-related powertrain components or systems, which are connected to a
computer.
5.2.4.3.3. Unless otherwise monitored, any other electronic powertrain component connected
to a computer relevant including any relevant sensors to enable monitoring
functions to be carried out, shall be monitored for electric/electronic circuit failures.
In particular, these electronic components shall be continuously monitored for any
electric circuit continuity failure, shorted electric circuits, electric range/performance
and stuck signal of the control system in accordance with Annex 2.
5.2.4.4. A sequence of diagnostic checks shall be initiated at each engine start and
completed at least once provided that the correct test conditions are met.
5.2.4.5. Activation of the Malfunction Indicator (MI)
5.2.4.5.1. The OBD system shall incorporate a malfunction indicator readily perceivable to the
vehicle operator. The MI shall not be used for any purposes other than to indicate
emergency start-up or limp-home routines to the driver. The MI shall be visible in all
reasonable lighting conditions. When activated, it shall display a symbol in
conformity with ISO 2575:2010, Symbol F.01. A vehicle shall not be equipped with
more than one general purpose MI used to convey power-train related failures
which may affect emissions. Separate specific purpose tell tales (e.g. brake system,
fasten seat belt, oil pressure, etc.) are permitted. The use of red colour for a MI is
prohibited.
5.2.4.5.2. For strategies requiring more than two preconditioning cycles for MI activation, the
manufacturer shall provide data or an engineering evaluation which adequately
demonstrate that the monitoring system is equally effective and timely in detecting
component deterioration. Strategies requiring on average more than ten driving
cycles for MI activation are not accepted.

5.2.4.9.1. One OBD system for both fuel types
5.2.4.9.1.1. The following procedures shall be executed for each diagnostic in a single OBD
system for operation on petrol and on (NG/biomethane)/LPG, either independent of
the fuel currently in use or fuel type specific:
(a) Activation of Malfunction Indicator (MI) (see Paragraph 5.2.4.5.);
(b) Diagnostic trouble code storage (see Paragraph 5.2.4.6.);
(c) Extinguishing the MI (see Paragraph 5.2.4.7.);
(d) Erasing a diagnostic trouble code (see Paragraph 5.2.4.8.).
For components or systems to be monitored, either separate diagnostics for each
fuel type can be used or a common diagnostic.
5.2.4.9.1.2. The OBD system can reside in either one or more computers.
5.2.4.9.2. Two separate OBD systems, one for each fuel type.
5.2.4.9.2.1. The following procedures shall be executed independently of each other when the
vehicle is operated on petrol or on (NG/biomethane)/LPG:
(a) Activation of Malfunction Indicator (MI) (see Paragraph 5.2.4.5.);
(b) Diagnostic trouble code storage (see Paragraph 5.2.4.6.);
(c) Extinguishing the MI (see Paragraph 5.2.4.7.);
(d) Erasing a diagnostic trouble code (see Paragraph 5.2.4.8.).
5.2.4.9.2.2. The separate OBD systems can reside in either one or more computers.
5.2.4.9.3. Specific requirements regarding the transmission of diagnostic signals from
bi-fuelled gas vehicles.
5.2.4.9.3.1. On a request from a diagnostic scan tool, the diagnostic signals shall be transmitted
on one or more source addresses. The use of source addresses is set out in
ISO 15031-5:2011.
5.2.4.9.3.2. Identification of fuel specific information can be realised as follows:
(a)
(b)
(c)
By use of source addresses;
By use of a fuel select switch;
By use of fuel specific diagnostic trouble codes.

5.2.6. Propulsion Family Definition with Regard to OBD and in Particular to Test Type VIII
5.2.6.1. A representative parent vehicle shall be selected to test and demonstrate to the
approval authority the functional on-board diagnostic requirements set out in
Annex 1 and if applicable to verify the Test Type VIII requirements laid down in
Annex 3 if this is applied by the Contracting Party based on the grade laid down in
Table 1 of Annex 2 and the propulsion family definition laid down in Annex 4. All
members of the family shall comply with the applicable requirements and
performance limits set out in this GTR.
5.2.7. Documentation
The vehicle manufacturer shall complete the information document in accordance
with the items listed in Annex 5 and submit it to the approval authority.

3.2. Except in the case of Grade A OBD, if available, the following signals in accordance with the
specifications in Paragraph 3.10. in addition to the required freeze-frame information shall be
made available on demand through the serial port on the standardised diagnostic connector,
if the information is available to the on-board computer or can be determined using
information available to the on-board computer: number of stored diagnostic trouble codes,
engine coolant temperature, fuel control system status (closed-loop, open-loop, other), fuel
trim, ignition timing advance, intake air temperature, manifold air pressure, air flow rate,
engine speed, throttle position sensor output value, secondary air status (upstream,
downstream or atmosphere), calculated load value, vehicle speed, the activated default
mode(s) and fuel pressure.
The signals shall be provided in standard units based on the specifications in Paragraph 3.10.
Actual signals shall be clearly identified separately from default value or limp-home signals.
3.3. For all control systems for which specific on-board evaluation tests are conducted as listed in
Table 2 of Annex 2 the results of the most recent test performed by the vehicle and the limits
to which the system is compared shall be made available through the serial data port on the
standardised diagnostic connector according to the specifications in Paragraph 3.12. For the
monitored components and systems excepted above, a pass/fail indication for the most
recent test results shall be available through the standardised diagnostic connector.
3.4. The OBD requirements to which the vehicle is certified and the major control systems
monitored by the OBD system in accordance with the specifications in Paragraph 3.10. shall
be made available through the serial data port on the standardised diagnostic data link
connector according to the specifications in Paragraph 3.8.
3.5. The software identification and calibration verification numbers shall be made available
through the serial port on the standardised diagnostic data link connector. Both numbers shall
be provided in a standardised format in accordance with the specifications in Paragraph 3.10.
3.6. The diagnostic system is not required to evaluate components during malfunction if such
evaluation would result in a risk to safety or component failure.
3.7. The diagnostic system shall provide for standardised and unrestricted access to OBD and
conform with the following ISO Standards or SAE specification:

3.12. The connection interface between the vehicle and the diagnostic tester shall be standardised
and meet all the requirements of ISO [DIS] 19689 "Motorcycles and Mopeds –
Communication between vehicle and external equipment for diagnostics – Diagnostic
connector and related electrical circuits, specification and use" or ISO 15031-3:2004 "Road
vehicles – Communication between vehicle and external test equipment for emissions-related
diagnostics – Part 3: Diagnostic connector and related electric circuits: specification and use".
The preferred installation position is under the seating position. Any other position of the
diagnostic connector shall be subject to the approval authority's agreement and be readily
accessible by service personnel but protected from tampering by non-qualified personnel. The
position of the connection interface shall be clearly indicated in the user manual.
3.13. The vehicle manufacturer may use an alternative connection interface upon request. Where
an alternative connection interface is used, the vehicle manufacturer shall provide an adapter
enabling connection to a generic scan tool. Such an adapter shall be provided in a
non-discriminating manner to all independent operators.
4. ACCESS TO OBD INFORMATION
4.1. Applications for approval or its amendments shall be accompanied by the repair information
concerning the vehicle OBD system. This information shall enable manufacturers of
replacement or retrofit components to make the parts they manufacture compatible with the
vehicle OBD system, with a view to fault-free operation assuring the vehicle user against
malfunctions. Similarly, such repair information shall enable the manufacturers of diagnostic
tools and test equipment to make tools and equipment that provide for the effective and
accurate diagnosis of vehicle control systems.
4.2. Upon request, the vehicle manufacturer shall make the repair information on the OBD system
available to any interested components, diagnostic tools or test equipment manufacturer on a
non-discriminatory basis:
4.2.1. A description of the type and number of preconditioning cycles used for the original approval
of the vehicle;
4.2.2. A description of the type of the OBD demonstration cycle used for the original approval of the
vehicle for the component monitored by the OBD system;
4.2.3. A comprehensive document describing all sensed components with the strategy for fault
detection and MI activation (fixed number of driving cycles or statistical method), including a
list of relevant secondary sensed parameters for each component monitored by the OBD
system and a list of all OBD output codes and format used (with an explanation of each)
associated with individual emission related powertrain components and individual
non-emission related components, where monitoring of the component is used to determine
MI activation.

4.2.8. Access to vehicle security features used by authorised dealers and repair shops shall be
made available to independent operators under protection of security technology according to
the following requirements:
(a)
(b)
(c)
(d)
Data shall be exchanged ensuring confidentiality, integrity and protection against
replay;
The standard https//ssl-tls (RFC4346) shall be used;
Security certificates in accordance with ISO 20828 shall be used for mutual
authentication of independent operators and manufacturers;
The independent operator's private key shall be protected by secure hardware.
4.2.8.1. The Contracting Parties will specify the parameters for fulfilling these requirements according
to the state of the art.
4.2.8.2. The independent operator shall be approved and authorized for this purpose on the basis of
documents demonstrating that they pursue a legitimate business activity and have not been
convicted of relevant criminal activity.

2.2. At a minimum the monitored devices with mandatory circuit diagnostics shall be the following:
Table 2
Overview of Devices (if fitted) to be Monitored in OBD Stage I
No.
Device Circuits Circuit Continuity Circuit Rationality Comment No.
Level, refer to 2.3.
Circuit High
Circuit Low
Open Circuit
Out of Range
Performance/
Plausibility
Signal stuck
Device operational/
Device present
1
1
2
3
4
5
6
7
8
9
10
11
Control module (ECU/
PCU) internal error
3 I
Sensor (input to control units)
Accelerator (pedal/
handle) position sensor 1 & 3 I I I I I I
Barometric pressure
sensor
Camshaft position
sensor
Crankshaft position
sensor
Engine coolant
temperature sensor
Exhaust control valve
angle sensor
Exhaust gas
recirculation sensor
Fuel rail pressure
sensor
Fuel rail temperature
sensor
Gear shift position
sensor (potentiometer
type)
Gear shift position
sensor (switch type)
1 I I I
3 I
3 I
1 I I I
1 I I I
1 & 3 I I I
1 I I I
1 I I I
1 I I I
3 I

Table 2 (Cont'd)
No.
Device Circuits Circuit Continuity Circuit Rationality Comment No.
Level, refer to 2.3.
Circuit High
Circuit Low
Open Circuit
Out of Range
Performance/
Plausibility
Signal stuck
Device operational/
Device present
1
Evaporative emission
system purge control
valve
Actuators (output control units)
2 I
2
3
Exhaust control valve
actuator (motor driven)
Exhaust gas
recirculation control
3 I
3
4 Fuel injector 2 I I
5 Idle air control system 1 I I I I
6
7
8
9
Ignition coil primary
control circuits
O exhaust sensor
heater
Secondary air injection
system
Throttle by wire
actuator
2 I I
1 I I I I
2 I I
3 I I (4)

2.8. Grade A Specific Test Requirements
2.8.1. If the OBD parameter requires the engine to be driven for MI activation, the vehicle shall be
driven as per driving cycle prescribed in GTR No. 2, or any driving cycle prescribed by
manufacturer including key On/Off cycles. The test vehicle can be considered meeting circuit
discontinuity testing when the MI activates within a maximum of 10 driving cycles.
2.8.2. If the OBD parameter does not require the vehicle to be driven for MI activation, the test
vehicle can be considered meeting circuit discontinuity testing for the tested OBD fault mode,
if the MI activates under the conditions described in Paragraphs 2.6.1., 2.6.1.1. and 2.6.1.2.

4. OBD ENVIRONMENTAL TEST PROCEDURE
4.1. The testing of OBD systems consists of the following phases:
4.1.1. Simulation of malfunction of a component of the powertrain management or emission-control
system;
4.1.2. Preconditioning of the vehicle (in addition to the preconditioning specified in GTR No. 2) with
a simulated malfunction that will lead to the OBD emission thresholds being exceeded, if the
Contracting Party applies these OBD fail thresholds as MI activation performance criteria;
4.1.3. Driving the vehicle with a simulated malfunction over the applicable Type I test cycle and
measuring the tailpipe emissions of the vehicle;
4.1.4. Determining whether the OBD system reacts to the simulated malfunction and alerts the
vehicle driver to it in an appropriate manner.
4.2. Alternatively, at the request of the manufacturer, malfunction of one or more components may
be electronically simulated in accordance with the requirements laid down in Paragraph 8.
4.3. Manufacturers may request that monitoring take place outside the Type I test cycle if it can be
demonstrated to the approval authority that the monitoring conditions of the Type I test cycle
would be restrictive when the vehicle is used in service.
4.4. For all demonstration testing, the Malfunction Indicator (MI) shall be activated before the end
of the test cycle.
5. TEST VEHICLE AND FUEL
5.1. Test Vehicle
The aged, test parent vehicle(s) or a new vehicle fitted with defective components or electrical
devices shall meet the propulsion unit family requirements laid down in Annex 4 and relevant
requirements laid down in GTR No. 2. The distance accumulation and ageing test procedure
is at the discretion of the Contracting Party.
5.2. The manufacturer shall set the system or component for which detection is to be
demonstrated at or beyond the criteria limit prior to operating the vehicle over the emissions
test cycle appropriate for the classification of the vehicle. To determine correct functionality of
the diagnostic system, the test vehicle shall then be operated over the appropriate Type I test
cycle at the discretion of the Contracting Party.
5.3. Test Fuel
The reference fuel to test the vehicle shall be specified by the Contracting Party and be of the
same specification as the reference fuel used to conduct the Type I tailpipe emissions after
cold start. The selected fuel type shall not be changed during any of the test phases. Where
LPG or NG/biomethane for alternative fuel vehicles are used as a fuel, the engine may be
started on petrol and switched to LPG or NG/biomethane (automatically and not by the driver)
after a pre-determined period of time.

8.4. OBD System Environmental Verification Tests
8.4.1. Vehicles fitted with Positive Ignition (PI) engines:
8.4.1.1. After vehicle preconditioning in accordance with Paragraph 8.2., the test vehicle is driven over
the appropriate Type I test.
8.4.1.2. The malfunction indicator shall activate before the end of this test under any of the conditions
given in Paragraphs 8.4.1.3. and 8.4.1.4. The approval authority may substitute those
conditions with others in accordance with Paragraph 8.4.1.4. However, the total number of
failures simulated shall not exceed four for the purpose of approval.
For bi-fuelled gas vehicles, both fuel types shall be used within the maximum of four
simulated failures at the discretion of the approval authority.
8.4.1.3. Electrical disconnection of the electronic evaporative purge control device (if equipped and if
active on the selected fuel type);
8.4.1.4. Electrical disconnection of any other component connected to a powertrain control unit/engine
control unit/drive train control unit in the scope of Annex 2.
8.4.2. Vehicles fitted with Compression Ignition (CI) engines:
8.4.2.1. After vehicle preconditioning in accordance with Paragraph 8.2., the test vehicle is driven in
the applicable Type I test.
The malfunction indicator shall activate before the end of this test. The approval authority may
substitute those conditions by others in accordance with Paragraph 8.4.2.2. However, the
total number of failures simulated shall not exceed four for the purposes of approval.
8.4.2.2. Electrical disconnection of any other component connected to a powertrain control unit/engine
control unit/drive train control unit in the scope of Annex 2.

Table 1 (Cont'd)
# Classification Criteria Description
OBD
Stage I
2.8. type of cooling system of combustion engine; X
2.9. combustion cycle (PI/CI/two-stroke/four-stroke/other); X
2.10. intake air system (naturally aspirated/charged (turbocharger/supercharger)/intercooler/boost
control) and air induction control (mechanical
X
throttle/electronic throttle control/no throttle).
3. POLLUTION CONTROL SYSTEM CHARACTERISTICS
3.1. operation principle of cold start or starting aid device(s); X
3.2. activation time of cold-start or starting aid device(s) and /or duty cycle (only
limited time activated after cold start/continuous operation);
3.3. propulsion unit (not) equipped with O sensor for fuel control; X
3.4. O exhaust sensor type(s); X
3.5. operation principle of O exhaust sensor (binary/wide range/other); X
3.6. O exhaust sensor interaction with closed-loop fuelling system
(stoichiometry/lean or rich operation).
Explanatory note:
X
X

2.1.2.10. A comprehensive document describing all sensed components concerned with the
strategy for fault detection and MI activation (fixed number of driving cycles or statistical
method). This shall, include a list of relevant secondary sensed parameters for each
component monitored by the OBD system. The document shall also list all OBD output
codes and formats (with an explanation of each) used in association with individual
emission-related powertrain components and individual non-emission-related components,
where monitoring the component is used to determine MI activation. This will contain, in
particular, a comprehensive explanation for the data given in service $05 Test ID $21 to
FF;
2.1.2.11. The information required in Paragraphs 2.1.2.1. to 2.1.2.10. may be provided in table form
as described in the following table;
Table 1
Example OBD Fault-code Overview List
Component
Diagnostic
trouble code
Monitoring
strategy
Fault detection
criteria
MI activation
criteria
Secondary
parameters
Preconditioning
Demonstration test
Intake air
temp.
sensor
open circuit
P0xx xxzz
Comparison >20°
with difference
temperature between
model after measured
cold start and
modelled
intake air
temperature
3rd cycle
Coolant and Two Type I Type I if
intake air
temperature
sensor
signals
cycles
Contracting
Party applies
MI
performance
criteria
2.1.2.12. Description of Electronic Throttle Control (ETC) Diagnostic Trouble Codes;
2.1.2.13. Description of Default Modes and Strategies in Case of ETC Failure;
2.1.2.14. Communication Protocol Information
The following information shall be referenced to a specific vehicle make, model and
variant, or identified using other workable definitions such as the Vehicle Identification
Number (VIN) or vehicle and systems identification:
2.1.2.14.1. Any protocol information system needed to enable complete diagnostics in addition to the
standards prescribed in Paragraph 3.8. of Annex 1., such as additional hardware or
software protocol information, parameter identification, transfer functions, "keep alive"
requirements, or error conditions;
2.1.2.14.2. Details of how to obtain and interpret all diagnostic trouble codes not in accordance with
the standards prescribed in Paragraph 3.11. of Annex 2;

On-board Diagnostics - Two or Three Wheeled Motor Vehicles.