Cycles and Default Modes in OBD - UNECE

EPPR OBD CG 26.09.2018

Cycles and Default

Modes in OBD

Copyright © 2018 CLEPA. All rights reserved. www.clepa.eu 2

• Request by Chair of EPPR OBD CG:

• CLEPA to provide explanatory material to show what is Default mode,

Permanent Default mode, key Cycle and Driving Cycle

1. Cycles in OBD Regulations

2. OBD Type Approval – Demo Testing

3. OBD Type Approval – Demo for OBD I

4. Default Modes

5. Significant Torque Reduction

EPPR OBD CG


2wh (L-category vehicle) OBD

cycles

Copyright © 2018 CLEPA. All rights reserved. www.clepa.eu

OBD CYCLES 1/3

• A driving event starts with the starter key being turned to the “key on/engine on” position and ends

with the key being turned to the “key off/engine off” position. For a combustion engine this means

starting of the engine. In real world usage the engine might only run in idle or may not reach a

complete engine start (defined in SAE standards) before being turned off. Normally, actual driving

on a road will follow.

• For emissions testing on the dyno, the term “driving cycle” is used:

definition “(41) ‘type I test’ means the applicable driving cycle used for emission approvals”,

driving cycle refers here to the applicable WMTC speed-time trace as test cycle.

• For OBD purposes, “driving cycle” has a different meaning and specifies a test cycle where all the

conditions necessary for a diagnostic monitor to perform and find a malfunction are met:

definition “(42) ‘driving cycle’ means a test cycle consisting of engine key-on, driving mode where a

malfunction would be detected if present, and engine key-off”.

For different diagnostics the driving mode necessary for malfunction detection and therefore the

driving cycle may be different, i.e. it is not one generic speed-time trace. “Driving cycle” for OBD

also refers to real world driving where “test cycle” means “driving event”.

• The “key cycle” is not defined in the regulation but as a demo test description. Its is meant for

demonstrating circuit continuity and certain rationality diagnostics in a simple way by just turning the

engine on and running idle, without the need for a dyno test. Interpretation: start is “key on/engine

on” (i.e. with engine running in idle), as “key on/engine off” would not be consistent with “driving

cycle” and MIL “bulb check” requirements. The definition of “driving cycle” includes the “key cycle”.



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OBD CYCLES 2/3

• For the OBD demo, the standard test cycle is the WMTC. An alternative demo cycle may be used if

it can be demonstrated that the WMTC is too restrictive and the alternative demo cycle covers real

world driving. This includes the option to use only running in idle if no OTL verification is necessary:

either using the “key cycle” demo test or for circuit continuity “demonstrate these failure modes

using driving conditions in which the component is used and the monitoring conditions are

encountered” *.

• EU regulations allow the completion of OBD tasks after “engine key off”: ‘3.2.3. Identification of

deterioration or malfunctions may also be done outside a driving cycle (e.g. after engine shutdown)’*

• IUPR requires a counter for the “ignition cycle”, which is not defined in the EU regulations, but in

SAE J1979: “Ignition Cycle Counter displays the count of the number of times that the engine has

been started.” This refers to the completed engine start, i.e. if the vehicle meets the engine start

criterion (the point when the engine reaches a speed 150 rpm below the normal, warmed-up idle

speed). An ignition cycle is any driving event with a completed combustion engine start.

• After a confirmed malfunction (with “MIL on”) has been “healed” during three consecutive driving

events without malfunction detection (“driving cycles”) the MIL may be switched off but the

confirmed DTC stays in OBD memory. It may only be erased after 40 “warm up cycles” without

malfunction detection. • "Warm-up cycle category 3 vehicle** " means sufficient vehicle operation such that the coolant temperature rises by at least 22 ºC from

engine start-up to at least 70°C If this condition is insufficient to determine the warm up cycle, with the permission of the approval authority,

alternative criteria and/or alternative signal(s) or information (e.g. spark plug seat temperature, engine oil temperature, vehicle operation

time, accumulative engine revolution, travel distance, etc.) may be adopted. In any case, all signal(s) and information used for determination

need to be monitored by the ECU and shall be made available by data stream.

** Reg. 2018/295 amending Reg. 44/2014 & 134/2014, from R83/05 1st amendment dated 5.02.2016

** GTR 18 ECE Trans 180a 18eEPPR OBD CG 26.9.2018


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OBD CYCLES 3/3

• The “warm up cycle” is not a specific speed-time trace but defines certain conditions which have to

be met during a real world driving event. There might be driving events where the “warm up cycle”

criteria are met but not the “driving cycle” criteria for a specific malfunction. In this case a

malfunction could not be detected but nevertheless the counter for the number of warm up cycles is

increased. Purpose: keep the information that a malfunction had been confirmed (with “MIL on”)

only for a limited time in OBD memory after healing with “MIL off”.

• Amendments to 44/2014

‒ “(42) ‘driving cycle’ means a test cycle consisting of engine key-on, driving mode where a malfunction would be detected if present, and

engine key-off;” *

‒ ‘3.2.3. Identification of deterioration or malfunctions may also be done outside a driving cycle (e.g. after engine shutdown).’; *

‒ ‘3.10. Additional provisions for vehicles employing engine shut-off strategies. 3.10.1. Driving cycle 3.10.1.1. Autonomous engine restarts

commanded by the engine control system following an engine stall may be considered a new driving cycle or a continuation of the

existing driving cycle.’; *

• Amendments to 134/2014

‒ “8.1.1. The Type I test need not be performed for the demonstration of electrical failures (short/open circuit). The manufacturer may

demonstrate these failure modes using driving conditions in which the component is used and the monitoring conditions are

encountered. These conditions shall be documented in the type approval documentation. “ *

‒ ‘1.2. The manufacturer shall make available the defective components or electrical devices to be used to simulate failures. When

measured over the appropriate test type I cycle, such defective components or devices shall not cause the vehicle emissions to exceed

by more than 20 percent the OBD thresholds set out in Annex VI(B) to Regulation (EU) No 168/2013.

For electrical failures (short/open circuit), the emissions may exceed the limits of set out in Annex VI(B) to Regulation (EU) No 168/2013

by more than twenty per cent.

When the vehicle is tested with the defective component or device fitted, the OBD system shall be approved if the MI is activated. The

OBD system shall also be approved if the MI is activated below the OBD threshold limits.’;

* Reg. 2018/295 amending Reg. 44/2014 & 134/2014), from R83/05 1st amendment dated 5.02.2016EPPR OBD CG 26.9.2018


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OBD Type Approval – Demo Testing 1/3

• “Three in a row” concept

– two “preconditioning” test cycles for 1st and 2nd malfunction detection (“pending”), (max. 9

allowed on request)

– 3rd test cycle for malfunction detection (“confirmed”) and emissions “verification” (for threshold

related monitors verification that the malfunctioning component/system is in the OBD threshold

limit (OTL) range (max. 120%) )

– if an alternative cycle for malfunction detection than the standard test cycle for emissions testing

is used,

then malfunction confirmation and OTL component verification are two separate steps

• “Preconditioning”

– standard OBD demo cycle is the same cycle as required for the Type I emissions test

– if for a diagnostic a cold start is required, the vehicle may be cold soaked also for the

preconditioning cycles

– at the request of the manufacturer, alternative “preconditioning methods” may be used -> meant

is additional preconditioning for the emissions “verification” allowed for the Type I emissions test

(for SI DI and CI)

– monitoring outside of the Type I test cycle (i.e. an alternative “preconditioning cycle”) may be

requested if it can be demonstrated to the type approval authority that the monitoring conditions

of the Type I cycle would be restrictive when the vehicle is used in service (i.e. under real world

driving conditions)



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Installation of hardware malfunction (component/system) (standard case) or electronic simulation

of such a failure (special case, at request of OEM) with emissions at OBD threshold limits (OTL) in full

useful life vehicle (or vehicle with full useful life aged exhaust system *)

“Preconditioning” of vehicle with malfunction

over two “preconditioning” cycles (standard case

Type I test cycle, at OEM request alternative cycle)

- malfunction detection

- “pending” fault entry in service $07

Emissions test drive with malfunction over

Type I test cycle

- malfunction detection

- “confirmed” fault entry in service $03

- if alternative cycle for malfunction detection

is used then this malfunction detection cycle

is an additional step

- OTL verification: to confirm that OBD

threshold component is in allowed range

up to max. 120% of OTL

Diagnostic is approved if MIL is activated in allowed OTL range, but also if activated below the OTL

OBD threshold limit (OTL)

emission limit (full useful life)

Em

issio

nemission level of full useful vehicle

(or full useful aged exhaust system)

without malfunction in Type I test

Emission with malfunctioning

component at max. 120% OTL

OBD OTL related Type Approval Demo

Also approved if MIL activated

below OTL



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Demo procedures for threshold related diagnostics



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OBD Type Approval – Demo for OBD I 1/2

• The OBD demonstration test requirements in Reg. 134/14 Annex VII are written for OBD threshold

(OTL) related component diagnostics (e.g. for TWC), but are in principle also applicable for circuit

continuity and rationality/performance monitoring (largely the same text as for EOBD)

‒ malfunctions must be demonstrated leading to emission above the OTL * in the Type I test cycle

‒ only for the electronic evaporative purge control device clarification that for the minimum test

“electrical disconnection” the Type I test is not required **.

• Reg. 44/2014 Annex XII Appendix 2 § 2.6 allows as exemption the detection of circuit continuity and

rationality/performance failures without preforming an emissions test by demonstrating that the

malfunction is detected and confirmed within 300 seconds after “key on” within one “key cycle”

‒ Key cycle” not defined in regulation – interpretation: start is “key on / engine on” (i.e. with engine

running in idle).

‒ Exemption from OBD verification test incl. the use of a new vehicle for the key cycle test

‒ No debouncing of failure via pending detections – “MIL on” in first driving cycle with malfunction

detection

* Reg. 134/2014 Annex VIII § 4.1.2. “… with a simulated malfunction that will lead to the OBD thresholds … being exceeded”

** Reg. 134/2014 Annex VIII § 8.3.1.5. “… For this specific failure mode, the type I test need not be performed”EPPR OBD CG 26.9.2018


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OBD Type Approval – Demo for OBD I 2/2

• Amendments for circuit continuity OBD demo requirements with Reg. 2018/295 *

• For electrical failures it is not necessary to use a Type I test.

• If a Type I test is used for the demo of an electrical failure the resulting emissions are

not evaluated OTL related as any level of emissions is allowed

‒ ‘1.2. The manufacturer shall make available the defective components or electrical devices to be

used to simulate failures. When measured over the appropriate test type I cycle, such defective

components or devices shall not cause the vehicle emissions to exceed by more than 20 percent

the OBD thresholds set out in Annex VI(B) to Regulation (EU) No 168/2013.

For electrical failures (short/open circuit), the emissions may exceed the limits of set out in Annex

VI(B) to Regulation (EU) No 168/2013 by more than twenty per cent.

When the vehicle is tested with the defective component or device fitted, the OBD system shall

be approved if the MI is activated. The OBD system shall also be approved if the MI is activated

below the OBD threshold limits.’;

‒ “8.1.1. The Type I test need not be performed for the demonstration of electrical failures

(short/open circuit). The manufacturer may demonstrate these failure modes using driving

conditions in which the component is used and the monitoring conditions are encountered. These

conditions shall be documented in the type approval documentation. “ *

Note: OBD allows in general the use of an alternative test cycle instead of the Type 1 test

cycle, e.g. “idle cycle”EPPR OBD CG 26.9.2018


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The EU regulations * use the term “default mode” for two different purposes

1. (permanent) default mode of operation for emission related components/systems:

‒ indicates that due to a detected malfunction a default or substitute value is being used – must be

shown in OBD summary table

‒ if this default mode is permanent (i.e. activated in the next driving cycle without the diagnostics

being performed again), the MIL must be switched on in the driving cycle where it was activated

‒ same requirements as in EOBD for cars/vans

‒ 2wheeler specific: use for “black MIL” – if malfunction leads to emissions above OTL, but the

activated default mode leads to emissions below the OTL, all OBD requirements like fault code

storage, tester communication etc. must be fulfilled, but MIL may be kept off. Emissions data must

be documented for default and non-default driving modes.

2. (permanent) default mode of operation leading to a significant torque reduction

‒ due to a failure a default mode is activated which significantly reduces torque (by 10% or more)

‒ independent of the effect on emissions, but a malfunction leading to a torque reduction could also

be emissions relevant

‒ 2wheeler specific requirement, i.e. nothing comparable in EOBD or CARB OBD

• Originally (Reg. 44/2014), all activated default modes must be shown in data stream –

this requirement was revoked with Reg. 2018/295• For regulatory text references see next pages

Default Modes in EU 2wh regulations

* Regulation 44/2014, Reg. 134/2014EPPR OBD CG 26.9.2018


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Due to failure of a component or system a substitute value needs to be used:

"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

Failure of an emission related component or system or of the OBD system itself

– detected by an emission related OBD diagnostic – substitute value usedFailure of other component or system

(i.e. not an emissions related OBD

malfunction and no influence on OBD

system) Default mode is only activated for

the driving cycle where the failure is

detected. In the next driving cycle

the component/system is used again

and the diagnostic can run again –

confirmation of malfunction possible

Default mode is permanently

activated. In the next driving cycles the

component/system is not used and the

diagnostic can not run – no


MI on after 3 driving cycles:

same behaviour as for emission

related malfunctions where no

default value is used

MI on with activation of

"Permanent emission default mode"

No mandatory OBD requirements

Default Modes in EU/ECE cars/vans regulation

Regulation R83/05 (up to 5th amendment)



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Default Modes in EU 2wh regulations

Due to failure of a component or system a substitute value needs to be used:

"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

Failure of an emission related component or

system or of the OBD system itself – detected

by an emission related OBD diagnostic –

substitute value used

Default mode is only activated for

the driving cycle where the failure is

detected. In the next driving cycle

the component/system is used again

and the diagnostic can run again –


Default mode is permanently

activated. In the next driving cycles the

component/system is not used and the

diagnostic can not run – no


MI on after 3 driving cycles:

same behaviour as for emission

related malfunctions where no

default value is used

MI on with activation of

"Permanent (emission) default

mode"

Failure of a powertrain component or system

triggering any programmed ‘limp-home’

operating mode which significantly reduces

engine torque - detected by an OBD diagnostic

and

/ or

In comparison to cars/vans for 2wh additional requirement to monitor for powertrain

faults triggering a default mode which significantly reduces engine torque


CLEPA proposal for definitions

• "Default mode" [or “limp-home 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;

• "Permanent default mode [or limp-home mode]" refers to a case where the engine management

controller permanently switches to a setting that does not require an input from a failed component or

system where such a failed component or system would result in an increase in emissions to a level

above the OBD threshold limits [given in paragraph XXX of this GTR] or if the OBD system is unable to

fulfil the basic monitoring requirements of this GTR or if the failure triggers an operation mode with a

significant torque reduction.

• Justification: cars/vans EOBD considers only emission related default modes. 2wh OBD additionally

considers failures of powertrain components or systems triggering any programmed ‘limp-home’

operating mode which significantly reduces engine torque. The default mode could either be only

active during the driving cycle the failure was detected in or it is permanently active. MI activation for

the first case is based on debouncing (standard case three driving cycles) by the OBD system, for the

second case the MI must be switched on when the permanent default mode is activated.

• In GTR 18 “limp-home" is specifically defined as 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“.

• Limp-home could either be used to designate specifically the default mode with significant torque

reduction (additional wording in GTR text necessary, often replacing or in addition to default mode) or

the default mode definition as proposed above includes significant torque reduction. In the latter case

limp-home could be completely deleted from the GTR.

Default Mode in 2wh GTR 18 – CLEPA proposals



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• Regulation 44/2014

• * (48) ‘permanent emission default mode’ refers to a case where the engine management controller

permanently switches to a setting that does not require an input from a failed component or system where

such a failed component or system would result in increasing emissions from the vehicle exceeding the OTL

[limits set out in Section (B) of Annex VI to Regulation 168/2013]

• ** 3.3.6. Unless otherwise monitored, any other powertrain component connected to a computer relevant for

the environmental performance and/or functional safety, triggering any programmed ‘limp-home’ operating

mode which significantly reduces engine torque, e.g. to safeguard powertrain components. Without

prejudice to the list Ap2-1 the relevant diagnostic trouble code shall be stored.

• ** 3.5.1. … The MI shall not be used for any purposes other than to indicate emergency start-up or limp-

home routines …

• ** 3.5.2. … The MI shall also activate whenever the powertrain control enters a permanent default mode of

operation leading to a significant torque reduction or if the OBD emission thresholds … are exceeded or if the

OBD system is unable to fulfil the basic monitoring requirements laid down in points 3.3.2 or 3.3.3.

• ** 3.6. … If the MI is activated due to deterioration or malfunction or permanent emission default modes of

operation, a fault code shall be stored that identifies the type of malfunction. …

• ** 3.6.3. The MI may be activated if a default mode is active without significant reduction of propulsion

torque.

• *** 3.2. (data stream) … the activated default mode(s) … **** the activated default mode(s)

The signals shall be provided in standard units based on the specifications … . Actual signals shall be clearly

identified separately from default value or limp-home signals.

Default Mode in EU 2wh regulations – legal text

Regulation 44/2014 * Annex XII **, Appendix 1 ***

***** Reg. 2018/295: Appendix 1 is amended as follows: (1) point 3.2. is replaced by the following:EPPR OBD CG 26.9.2018


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• Regulation 44/2014 Annex XII

• *** Figure Ap1-1 Template OBD information list (“summary table”): for each diagnostic in last column if

“Default mode” active

• **** 2. … electric circuit malfunctions which may cause emissions to exceed the designated OBD

emission thresholds … and/or lead to activation of a default mode that results in a significant

reduction of propulsion torque.

• **** Table Ap2-1 footnote (1) Only in case of an activated default mode leading to a significantly

reduced propulsion torque or if a throttle by wire system is fitted.

• Regulation 134/2014 Annex VIII

• 3.4. The list with PCU/ECU malfunctions shall be provided pursuant to the requirements referred to in

Number C11 of Annex II of Regulation (EU) No 168/2013 as follows:

3.4.1. for each malfunction that leads to the OBD emission thresholds set out in Part B of Annex VI to

Regulation (EU) No 168/2013 in both non-defaulted and defaulted driving mode being exceeded.

The emission laboratory test results shall be reported in those additional columns in the format of the

information document referred to in Article 27(4) of Regulation (EU) No 168/2013;

• Regulation 901/2014 Administrative provisions

‒ ETC = electronic throttle control

Default Mode in EU 2wh regulations – legal text

Regulation 44/2014 * Annex XII **, Appendix 1 ***, Appendix 2 **** EPPR OBD CG 26.9.2018


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• LDV Regulation R83/05 (up to 5th amendment)

• 2.14. "Permanent emission default mode" refers to a case where the engine management controller

permanently switches to a setting that does not require an input from a failed component or system

where such a failed component or system would result in an increase in emissions from the vehicle to

a level above the OTL [limits given in paragraph 3.3.2. of this annex].

• 3.5.1. … The MI shall not be used for any purposes other than to indicate emergency start-up or

limp-home routines …

• 3.5.2. … The MI shall also activate whenever the powertrain control enters a permanent default

mode of operation if the OTL [emission thresholds] … are exceeded or if the OBD system is unable

to fulfil the basic monitoring requirements laid down in paragraphs 3.3.3. or 3.3.4.

• 3.6.1. … If the MI is activated due to deterioration or malfunction or permanent emission default

modes of operation, a fault code shall be stored that identifies the type of malfunction. …

• 3.2. (data stream) …

The signals shall be provided in standard units based on the specifications … . Actual signals shall be

clearly identified separately from default value or limp-home signals.

• Conclusion: EOBD for LDV requires MI activation for confirmed malfunctions and for

pending/confirmed malfunctions if a permanent default mode of operation is activated.

Permanent means that in the driving cycle with fault detection and any following driving cycles the

diagnostics cannot run anymore due to the permanent default mode of operation. If the default mode is

only activated for the driving cycle with fault detection and not active in the next driving cycle so that

the diagnostics can run and could find the fault again if present, MI must only be activated with a

confirmed malfunction.

Default Mode in EU/ECE cars/vans reg. – legal text



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• EU OBD for L-category vehicles introduces as a new concept to OBD I the requirement to

detect malfunctions that cause the ECU/PCU to trigger a default operating mode

which significantly reduces engine torque

• ‘Significant reduction of propulsion torque’ means a propulsion torque less than or equal

to 90 % of torque in normal operation mode

• Significant reduction of propulsion unit torque indicates* a

‒ serious environmental problem or

‒ any other serious failure which leads to and requires a significant torque reduction

• The intention is to warn the rider in case of torque reduction triggered by the ECU / PCU

and to store the relevant information for the workshop to enable the technician to

discuss the behavior with the customer

• The regulations assume that these malfunctions concern powertrain components

connected to a computer relevant for the environmental performance and/or functional

safety

• Indicated examples* for torque limitation methods for SI combustion engines:

‒ Cap or reduce fuel delivery

‒ Cap or reduce air delivery

‒ Retard spark delivery

Significant torque reduction - summary



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* EU COM at UN EPPR: On-board diagnostic performance criteria for

MI activation: EPPR-07-21e.ppt

https://www2.unece.org/wiki/download/attachments/23101475/EPPR-07-21e.ppt?api=v2


EU COM EPPR 2014• At a later stage to be included, OBD related to functional safety

- First step, warn rider in case of torque reduction triggered by engine management system;

- Future: ISO 26262 on functional safety.

EPPR-07-21 *

… the ECU/PCU triggered a torque limiting default mode which is permanently applied in the key cycle

only if resulting in a significant reduction of propulsion unit torque (noticeable by the grand majority of

riders).

MIL on required if default mode causes torque limitation below threshold (90% or less of normal torque)

but may be activated at lower levels of torque reduction

Significant torque reduction - EU COM explanation

* EU COM at UN EPPR:

On-board diagnostic

performance criteria for

MI activation: EPPR-07-21e.ppt

Torque limiting default mode

https://www2.unece.org/wiki/download/attachments/23101475/EPPR-07-21e.ppt?api=v2

Thank you for your attention!

www.clepa.eu

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Cycles and Default Modes in OBD - UNECE