COMMISSION NOTICE

Guidance on the identification of the presence of Defeat Devices with regards to emissions of light-duty vehicles approved with Real Driving Emissions (RDE), heavy-duty vehicles and on anti-tampering protection

(2023/C 68/01)

DISCLAIMER This guidance notice complements Notice C(2017) 352 final, which addressed the presence of defeat devices in pre-RDE light-duty vehicles. It reflects the discussions of the expert meetings of the Forum on Type Approval and Market Surveillance. The meetings involved the Commission services and experts from the Member States. It is intended to facilitate the implementation of Regulation (EC) No 715/2007 (1) and Regulation (EC) No 595/2009 (2) for light and heavy-duty vehicles respectively. It is itself not legally binding. Any authoritative reading of the law should only be derived from those Regulations and other applicable legal texts or principles, like Commission Regulation (EU) No 2017/1151 (3) and Commission Regulation (EU) No 582/2011 (4) including all their amending acts. While this note seeks to assist authorities and operators by presenting good practices for an effective implementation of the applicable law, only the Court of Justice of the European Union is competent to authoritatively interpret Union legislation.

1.   Introduction

The concept of a defeat device is an integral part of European vehicle emissions legislation. Both the definition and the prohibition (including some exceptions) of defeat devices for light-duty vehicles are clearly spelled out in Regulation (EC) No 715/2007, Articles 3(10) and 5(2). For heavy-duty vehicles this prohibition is prescribed in Regulation (EC) No 595/2009, Article 5(3) (see Annex I).

The compatibility of certain kind of defeat devices has been subject of several requests for a preliminary ruling before the Court of Justice. The Court has addressed this question in case C-693/18, where the Court considered, that the exception to the prohibition on the use of defeat devices must be interpreted strictly (5). Furthermore, the Court has decided in cases C-128/20, C-134/20 and C-145/20, that a defeat device which, under normal driving conditions, operated during most of the year in order to protect the engine from damage or accident and ensure the safe operation of the vehicle could not fall within the exception provided for in Article 5(2)(a) of Regulation (EC) No 715/2007 (6).

In early 2017, the Commission published a first guidance on Auxiliary Emission Strategies (AES) and Defeat Devices (7), with respect to light duty vehicles type approved without a Real Driving Emissions (RDE) tests. That first guidance also included detailed guidance on the evaluation of AES that subsequently became part of the legislation and therefore is not repeated in this document.

The intention of the present document is to set good practices for the detection of illegal defeat devices for both light and heavy-duty vehicles, complementing the first guidance notice, with particular emphasis on vehicles type approved under the Euro 6d and 6d-temp and Euro VI steps A to E.

At the same time, this document also addresses the need to protect vehicles from tampering, by promoting appropriate testing of the emission control systems and testing of the vehicle odometer, as part of market surveillance.

A draft of this document was discussed with the Member States in the FORUM for exchange of information on enforcement and with all stakeholders in the Motor Vehicles Working Group. Comments were received and were taken into account to the extent possible.

PART A: Defeat Devices and AES

2.   Definitions and generic obligations:

In the case of Light-Duty Vehicles:

The concept of defeat devices in the case of light-duty vehicles is defined in Regulation (EC) No 715/2007, Article 3 (10):

‘defeat device’ means any element of design which senses temperature, vehicle speed, engine speed (RPM), transmission gear, manifold vacuum or any other parameter for the purpose of activating, modulating, delaying or deactivating the operation of any part of the emission control system, that reduces the effectiveness of the emission control system under conditions which may reasonably be expected to be encountered in normal vehicle operation and use;

The prohibition to use defeat devices and exceptions are laid down in the same Regulation, Article 5(2):

‘The use of defeat devices that reduce the effectiveness of emission control systems shall be prohibited. The prohibition shall not apply where:

(a)	the need for the device is justified in terms of protecting the engine against damage or accident and for safe operation of the vehicle;

(b)	the device does not function beyond the requirements of engine starting; or

(c)	the conditions are substantially included in the test procedures for verifying evaporative emissions and average tailpipe emissions.’

The prohibition needs however to be read together with the rules laid down in Commission Regulation (EU) 2017/1151 for what concerns the use of Auxiliary Emission Strategies.

The relevant definitions are laid down in Regulation (EU) 2017/1151, Article 2:

And Article 5 (11):

According to Annex IIIA of Regulation (EU) 2017/1151, the following applies:

In the case of Heavy-Duty Vehicles:

For HDV, the concept of defeat strategy is defined in Regulation (EC) No 595/2009, Article 3(8):

In the following, the term defeat devices is to be read to include also defeat strategies for HDV. The prohibition to use defeat strategies are laid down in the same Regulation, Article 5(3) of Regulation (EC) No 595/2009:

A substantial difference between the two regulations is that for light-duty vehicles exceptions are placed on the defeat devices, while for heavy duty vehicles, the exceptions are mentioned on the use of Auxiliary Emission Strategies in UNECE Regulation No. 49 (8) Revision 6, Annex 10, paragraph 5.1.2:

‘An AES shall not reduce the effectiveness of the emission control relative to a BES under conditions that may reasonably be expected to be encountered in normal vehicle operation and use, unless the AES satisfies one the following specific exceptions:

(a)	Its operation is substantially included in the applicable type-approval tests, including the off-cycle test procedures provided for in paragraph 6 of Annex VI to this Regulation and the in-service provisions set out in Article 12 of this Regulation (9).

(b)	It is activated for the purposes of protecting the engine and/or vehicle from damage or accident;

(c)	It is only activated during engine starting or warm up as defined in this annex;

(d)

Its operation is used to trade-off the control of one type of regulated emissions in order to maintain control of another type of regulated emissions under specific ambient or operating conditions not substantially included in the type approval or certification tests. The overall effect of such an AES shall be to compensate for the effects of extreme ambient conditions in a manner that provides acceptable control of all regulated emissions.’

3.   Rationale

3.1.    Defeat Devices in Light-Duty Vehicles

Tailpipe emissions levels have to remain below the emission limits both in WLTP and RDE tests performed according to the Regulation (EU) 2017/1151. According to the exceptions of the defeat device definition, the prohibition of a defeat device does not apply within the boundary conditions included in the test procedures for emissions. This exception was introduced since the emissions in any regulatory test have to remain in any case below the limits.

Therefore, in vehicles type approved with RDE, while the RDE boundary conditions are wide enough, there is still a high risk of defeat devices in the areas that are not tested, i.e. outside the RDE boundary conditions.

Detecting that a test is being performed and purposefully changing the emission behaviour of a vehicle in order to show lower emissions than what otherwise it would have emitted, should also be considered as a prohibited defeat device. Similarly, an AES that has not been declared and therefore evaluated, would automatically qualify as a defeat device. Therefore, the following mentions of defeat devices might include AES that were not declared and approved. Type approval authorities should provide the corresponding declared and approved AES upon request to the market surveillance authority (10), the Commission or other recognised third parties which perform relevant tests.

It is worth noting that checking for defeat devices may also include other types of emissions tests, such as the one for evaporative emissions (Type 4 test).

3.2.    Defeat Devices in Heavy-Duty Vehicles

The provisions for In-Service Conformity (ISC) in Regulation (EU) No 582/2011 introduce the verification of the conformity of emissions on vehicles using PEMS. The demonstration test conducted at type approval and the ISC tests ensure that the engine emissions will remain below the emission limits, giving confidence that the vehicle would comply with them under all normal conditions of use.

Detecting that a test is being performed and purposefully changing the emission behaviour of a vehicle in order to show lower emissions than what otherwise would have been emitted, should also be considered a prohibited defeat device/strategy in the case of HDV. Similarly, an AES that has not been declared and therefore evaluated, would automatically qualify as a prohibited defeat device/strategy. Therefore, in the following text mentions to defeat devices might include AES that were not declared and approved.

While the permitted testing conditions for PEMS tests are wide enough, there is still a high risk of defeat devices in areas that are not tested, which may still exist outside the ISC-PEMS permissible testing conditions.

4.   How to detect a potential defeat device

For the purpose of assisting the Member States authorities with their obligations, the present document introduces a methodology to detect defeat devices. The main objectives are:

—	To ensure a consistent vehicles selection and ‘defeat devices testing’;

—	To set out a recommended methodology with the aim to ensure consistency in the testing and assessment between different authorities/laboratories. The said methodology introduces non-regulated testing conditions (or categories of non-regulated testing conditions) which might trigger a defeat device.

4.1.    Vehicle selection

In line with Regulation (EU) 2018/858 (11) and ‘when carrying out those tests and inspections’, the involved parties (Commission, Authorities) ‘should take account of established principles of risk assessment’ (12), which are discussed within the Forum for the Exchange of Information on Enforcement of the EU legislation on the approval and market surveillance of motor vehicles. For that purpose, several criteria may be considered to build a sample of vehicles to be checked:

—

Market share: Preferably sales numbers directly available within an EU Member State are to be used. For Light-Duty Vehicles, sales data in most recent CO2 monitoring database found in https://www.eea.europa.eu/data-and-maps/data/co2-cars-emission-20 and https://www.eea.europa.eu/data-and-maps/data/vans-16 (or its latest yearly version) could be used. For both light and heavy-duty vehicles, it is recommended that the testing starts from the vehicles with the higher sale numbers EU-wide. However also vehicles with lower sale numbers need to be tested in order to increase randomness of testing.

—	Technical definition: Emissions standards, powertrain technology, fuel and after-treatment could be considered as a second criterion.

—

Environmental performance: information on the real-world emissions performance of vehicles may be available from alternative methods, such as remote testing, on-board monitors, etc. Although these pieces of information do not constitute the basis for confirming the presence of a defeat device, they provide an indication for identifying anomalous cases. When established in a robust manner (well defined testing protocols, large number of vehicles tested according to the same protocol), they might constitute a good basis to establish the environmental performance of the vehicles, and could be used to select vehicles for further testing. Several techniques and data sources might be used to establish the possible environmental performance of vehicles. Two of them are recommended and briefly presented below: The following techniques are recommended:

—

Remote fleet monitoring with on-board sensors (e.g. NOx, engine) also referred to as ‘Simplified Emissions Measurement Systems’ (SEMS). This option might represent an intermediate way to correlate high emissions with engine and vehicle operating parameters, but the data evaluation strategies remain to be defined.

—

Remote Sensing Devices (RSD) monitor many vehicles at a fixed location or with mobile unit (chase test). The RSD data need to be used in conjunction with an access to registration databases to determine the relationship with the vehicle type and its applicable emissions standard. Conclusive information is obtained once a significant number of vehicles of the same type are found to be high emitters.

To make such data available, a Joint Action on Remote Sensing and Risk Assessment for Emission Compliance has been launched, as an initiative of the EU Member States Market Surveillance and Type Approval Authorities under the EU Forum for Exchange of Information on Enforcement. Research projects CARES (13) and NEMO (14) developed user friendly and accurate remote monitoring systems for emissions. The objective of this action will be to develop a methodology to gather and to share vehicle emissions data from RSD and other techniques, with a view to support the risk assessment methodology for vehicle type selection.

Other techniques might be considered to identify the highest emitters provided that the vehicle environmental performance is assessed under similar testing conditions (e.g. testing vehicles in a laboratory under driving cycles and/or conditions that differ from the regulatory test).

The vehicle information required by the legislation (15) needs to be made available to all relevant parties (Member States, Technical Services, third parties and the Commission) in order to allow testing.

4.2.    Testing Methodology for Defeat Devices and Evaluation of results

4.2.1.   Introduction

The methodology introduced in this section will be subject to a regular review by the Forum for the Exchange of Information on Enforcement of the EU legislation on the approval and market surveillance of motor vehicles. Using the latest emissions data collected by the participating authorities, the review will assess the suitability of the emissions thresholds introduced in paragraph 4.2.3.1.

The following includes various options for testing and not all methods shown below need to be applied on every test vehicle. The competent authority or recognised third party should decide case by case which methods are best suited, based on an appropriate risk assessment which takes into account possible non-compliance, the likelihood of its occurrence, and other possible indicators, like the severity of the occurrence.

The search for defeat devices (DD) could include two distinct cases:

Case A) ‘Boundary detection DD”: devices/strategies that use the currently regulated test boundaries or surrogates thereof as triggers (such as ambient temperature, altitude, trip duration, fuel consumed and driving dynamics ranges) or;

Case B) ‘Test detection DD’: devices/strategies triggered by the presence of test equipment (e.g. backpressure increase at the tailpipe, signals on rear ultrasonic sensors, connection of a data recorder on the OBD port) or the vehicle localization (i.e. anything informing the vehicle that it is being tested on road for tailpipe emissions). These ‘Test detection DD’ apply primarily to on-road tests with PEMS, since vehicles tested in the laboratory usually need to use a special ‘chassis dynamometer mode’ in order to allow emissions testing without triggering safety devices etc.

The approach followed for both cases is illustrated in the following table. Though ‘Boundary Detection’ represents the main focus, investigations to detect ‘Test Detection’ cannot be neglected as the risk to see such strategies could increase over time.

Table 1

Distinct cases of Defeat Devices

	Case A Boundary detection	Case B Test detection
Test equipment	According to the regulatory requirements (Lab, PEMS)	Limited interference to the vehicle (no connection to the vehicle OBD port, possibly no exhaust flow meter) such as: car plume chasing, SEMS.
Selection of test conditions	According to paragraph 4.2.2.1	In addition to Case A possibility to conduct road tests at different locations would mitigate the risk of a strategy making use of the vehicle position.
Assessment of emissions data	According to paragraph 4.2.3	Ad-hoc

4.2.2.   Testing for Case A (Boundary detection)

4.2.2.1.   Selection of testing conditions (modalities)

For all cases it is necessary as a minimum to include testing the vehicle with the regulatory methodologies. This is an important step in order to make sure that the vehicle/engine is free of malfunctioning, bad maintenance or other similar issues, which would unduly increase the level of emissions.

To detect the presence of defeat devices according to Case A, it is necessary that the vehicles are tested under variations of the standard testing conditions referred to as ‘modalities’. The set of modalities is not fixed but instead kept open due to the need to detect specific technology behaviours in response to a complex set of parameters and the need to keep a non-predictable character.

These general principles are illustrated in Table 2 for light and heavy-duty vehicles (16).

Table 2

Emissions standards, regulatory emissions tests and possible modalities for case A

Emissions standards	Applicable regulatory emissions test(s)	Possible modalities for DD detection
Light-Duty Vehicles
Euro 5 Euro 6b,c	NEDC according to UNECE R83 (17)	Modified NEDC, other cycles, elimination of all recognizable conditions typical of bench testing (open bonnet, wheels not rotating, lack of GPS signal or of wheel movement, etc), auxiliaries on, on-road tests
Euro 6d-Temp Euro 6d	WLTP according to EU Reg. 2017/1151 RDE tests according to EU Reg. 2018/1832	Modified WLTP, on-road WLTP for comparison, other cycles, elimination of all recognizable conditions typical of bench testing (open bonnet, wheels not rotating, lack of GPS signal or of movement, etc), auxiliaries on, On-road tests outside the RDE ‘boundary conditions’ (e.g. outside RDE altitude and/or temperature and/or driving dynamics ranges)
Heavy-Duty Engines/Vehicles
Euro VI	WHTC in case of engines testing and PEMS test of whole vehicles according to Commission Regulation (EU) No 582/2011 (18)	On-road or laboratory vehicle tests (e.g. equivalent WHVC with phases in different order) outside the ISC ‘permissible conditions’ (e.g. outside altitude and/or temperature)

By modifying one or several of the test parameters with respect to the emissions test, one might trigger one or more of the following cases, which may result in increased emissions:

—	A defeat device.

—

An AES.

—	A modified physical response of the engine and/or emissions control technologies, naturally caused by the change of conditions (e.g. ambient temperature affecting the warm-up of components) but not controlled by software in response to sensed signals/parameters (19).

The ‘modalities’ are sets of testing conditions under which increases in emissions and therefore devices/strategies might be observed. For tests lasting between 30 minutes (typical laboratory duration) and a maximum of 2 hours (light-duty) or even 3 hours (heavy-duty), the effect of an emissions increase caused by an AES can be observed if:

—	The AES/DD is activated for a sufficient duration.

—	The corresponding emissions increase is not statistically diluted over the total emissions of the entire test.

It is therefore recommended to test using the ‘best available modalities’: the shorter, the better to detect short AES activations, provided that the minimum modality duration is in line with the recommended practice from paragraph 4.2. Modalities with long durations may also be considered, e.g. for situations where the engine load remains elevated for a long period (e.g. conditions with high payload and/or climbing and/or motorway driving).

4.2.2.2.   Categorisation of modalities

To facilitate the assessment of the emissions obtained for various modalities, categories were created and associated with the thresholds in paragraph 4.2.3.1. This applies only to case A (boundary detection).

—

Category 1 includes all the regulated tests such as Cold WLTP, cold and hot RDE urban and total tests, regulated ISC-HDV, and for which emissions limits apply. This category also includes tests with limited changes when compared to the regulated conditions (e.g. AC on during a cold WLTP, hot WLTP, cold and hot WHVC): in this case, the parameters outside the regulated testing conditions should not lead to a significant change in the physical response of the engine system).

—	Category 2 includes non-regulated tests whose distances are in the order of magnitude of the distances from the regulatory tests.

—	Category 3 includes all other tests not falling within categories 1 and 2 or allowing for ‘surprise testing’. This category also includes the tests to determine whether the vehicle adapts its strategy during tailpipe emissions tests (case B).

When defining a modality and attributing it to one of the categories, the responsible authority should carefully consider the following characteristics:

—

The modality driven distance (or duration): the minimum distance (or duration) should be in line with the values set by the regulated conditions. For light-duty vehicles, the minimum recommended distance is 16 km (i.e. the minimum regulated distance of an RDE test). For heavy-duty vehicles, the minimum recommended duration needs to correspond to the work of the engine on the WHTC cycle. For hybrids vehicles (e.g. PHEVs), the share of EV driving should be considered.

—	Shorter modalities may be used but in that case the thresholds in paragraph 4.2.3.1 would not apply and ad-hoc evaluation strategies should be adopted (see paragraph 4.2.3.2);

—	The vehicle conditioning, i.e. if the modality corresponds to a test for which the vehicle is ‘cold’ according to the definition of the applicable Regulation (example: first phase of the WLTP).

Table 3

Examples of testing modalities within the different categories

Category	Light-Duty	Heavy-Duty
1	— WLTP — WLTP with an open door bonnet, rolled-down windows, lights and AC on,.... — RDE compliant routes (total or urban phases) under moderate or extended conditions	— ISC-PEMS compliant routes for whole vehicle testing — WHTC engine tests
2	— WLTP on a test track — WLTP in the laboratory variations in the ambient temperature, repetition of selected phases of the test cycle — WLTP with repeated or re-ordered phases, all at any ambient temperature between -7°C and +35°C. — Other laboratory cycles, as complete cycles or phases (e.g. CADC (20), BAB (21), TfL (22)) — RDE non-compliant tests (23), e.g (24).: — Excess of driving dynamics. — Excess of cumulative altitude gain. — Specific tests addressing driving conditions which cannot be covered with an RDE test, e.g. long motorway route. — Tests outside the RDE boundary conditions for ambient temperature and/or altitude.	— WHVC laboratory tests for vehicle testing — Other laboratory cycles. (i.e. several WHVC with changes in the order of the phases; e.g. U/R/M/M/R/U (25)) — ISC-PEMS routes resulting as non-compliant from e.g.: — Low payload; — Specific tests addressing driving conditions which cannot be covered with an ISC-PEMS test: short urban route, long motorway route; — Tests outside the ISC-PEMS permissible conditions for ambient temperature and/or altitude.
3	Modified evaporative emissions test, OBD functional checks, plume chasing, RDE with and without connection to OBD or SEMS	OBD functional checks, plume chasing, PEMS tests without connection to OBD

NB1:	Examples of a test matrices are given in Annex III.

NB2:	The classification of the tests within the different categories is the responsibility of the TAA and needs to be supported by the AES declarations delivered at type approval.

4.2.3.   Evaluation of the test results for Case A (Boundary detection)

The vehicle tailpipe emissions over the entire test (or section of the test) should be expressed as ‘Emissions Ratios’ (ER). The ER is defined as the vehicle emissions during the test divided by the applicable emissions limit (26).

For light-duty vehicles, the ER is to be calculated considering the provisions of Regulation (EU) 2017/1151 as they applied at the time of type approval. For the modalities under non-regulated emissions (i.e. within categories 2 and 3 defined in paragraph 4.2.2.2), the corrections for extended conditions and/or CO2 are not applicable.

For heavy-duty vehicles, the ER is to be calculated considering the provisions of Regulation (EU) No 582/2011 as they applied at the time of type approval.

For the pollutants without conformity factors and unregulated under real driving conditions (e.g. CO for RDE-LDV tests), the on-road emissions need to be divided by the applicable limit. In such a case, the calculated ER is not used to verify the vehicle compliance but rather to assess whether the emissions are anomalous according to paragraphs 4.2.3.1 and 4.2.3.2.

Table 4

Numerical examples #1 for ER calculation : Light-duty

	Measured emissions	Applicable emissions limit (Euro 6, positive ignition)	PEMS Conformity Factor	ER Calculation
Laboratory (Bag)	NOx 35 mg/km	60 mg/km	NA	ER = 35 / 60 = 0,58
Laboratory (PEMS for Euro 6d vehicle)	NOx 35 mg/km	60 mg/km	1,43	ER = 35 / (60 x 1,43 ) = 0,41
On-road (PEMS for Euro 6d vehicle)	NOx 35 mg/km	60 mg/km	1,43	ER = 35 / (60 x 1,43 ) = 0,41

Table 5

Numerical examples #2 : Heavy-duty

	Measured NOx emissions	Applicable emissions limit (Euro VI, compression ignition)	PEMS-ISC Conformity Factor	ER Calculation
On-road (PEMS for Euro VI vehicles)	125 mg/kWh	460 mg/kWh	1,5	ER = 125 / (460 x 1,5 ) = 0,18

4.2.3.1.   Method A: ER versus emissions thresholds (Categories 1 & 2)

In principle, the main goal for AES provisions is to allow for vehicle/engine protection under exceptional and extreme operating circumstances, and only if alternative method/technologies that do not require the AES (27) are not available. Therefore, the acceptance of an AES by a type approval authority should carefully consider the environmental impact and the frequency of the AES. Both the frequency and environmental impact of an AES should be limited to the maximum extent possible.

This method A is by no means an encouragement to exceed the emissions limits, even under non-regulated conditions. Its primary objective is to detect the presence of AESs and to prioritize investigations. The thresholds proposed below are based on the lessons learnt using the test data from vehicles of different emissions standards and technologies. Emissions ratios below these thresholds and above the applicable limits (corresponding to a threshold value of 1) may still be caused by illegal strategies. For vehicles type approved by earlier versions of Regulation (EC) No 715/2007 the thresholds contained in the previous Guidance note apply.

Table 6

Emissions Thresholds Euro 6d-TEMP and 6d (LDV) / Euro VI (HDV)

	Category 1	Category 2
Threshold 1	1,05	1,3
Threshold 2	1,3	2,5

Thresholds apply to all regulated pollutants, with the exception of THC (when not measured with PEMS for light-duty vehicles).

4.2.3.2.   Method B: ER Relative analysis (Categories 2 and 3)

In addition to the analysis using the thresholds from paragraph 4.2.3.1, the ER values may be compared to the values obtained for properly functioning vehicles for the same pollutants and modalities.

Using this method, a vehicle may be classified as ‘statistical outlier’ as soon as its emissions deviate from the ones observed for its technology group under the same conditions. This approach requires a significant amount of ‘historical’ emissions data from different vehicles.

The method should improve over time as the ‘picture’ for correctly functioning vehicles gets clearer with the increasing number of tests. Currently, it may be applied using the data collected for light-duty Euro 6d-TEMP and 6d vehicles, for instance using the data presented in the JRC 2019 annual report on emissions (28).

4.2.3.3.   Decision diagrams

4.2.4.   General approach for Case B (Test Detection)

In this case, devices/strategies are triggered by the PEMS test equipment or the vehicle localization. It is therefore recommended to vary these parameters using the best available practices.

For the detection of the PEMS test equipment: the vehicle should preferably be tested under conditions (e.g. a test track using the cycles suggested in paragraph 4.2.2.1) exhibiting a sufficient degree of repeatability. This should allow the comparison between tests conducted using standard PEMS equipment (with EFM and OBD connection) and measurement equipment totally independent from the vehicle (i.e. no EFM and OBD connection, possibly with simpler equipment such as SEMS).

For the detection of the vehicle localization, conducting RDE compliant tests at different locations and frequently varying the locations should significantly mitigate the risk of having such strategies.

4.2.5.   Complementary analysis

4.2.5.1.   Detailed Emissions analysis

In cases where the test results are close to the emission thresholds or in order to understand better what triggers an AES, the test results might also be analysed by subsets, e.g. phases of the laboratory driving cycles, on-road driving conditions (urban, rural, motorway).

As example for this analysis, the emissions ratios between the urban and motorway driving conditions can highlight different emissions strategies and their respective efficiency, as the engine load is significantly different between these two conditions. For this type of complementary analysis, the results cannot be checked against the method A introduced earlier in the document. They should be analysed in a relative manner, i.e. comparing the results to the best or worst cases obtained for the same fuel, emissions standard and/or emissions control technologies.

4.2.5.2.   Analysis of Engine Control Module (ECM)

In case of suspicious test results, or if there are indications for the use of defeat devices, suspicion may be substantiated or invalidated by software analysis. The disclosure of the engine control module (ECM) software and the functional framework/Software documentation is requested together with the complete set of A2L and Hex-Files which declare the actual applied variable and data values on the ECM from the manufacturer. The ECM software is put under investigation concerning functions that may cause unauthorized modulation or shutdown of emission reducing systems.

Possible defeat devices can be verified in RDE measurements by checking emission control system performance under conditions previously detected by software analyses (e.g. re-entry of catalyst heat-up, variation of ambient temperature, etc.) Results from software analyses should be verified in any case by additional physical tests with PEMS or other suitable measurement tools. Findings resulting from these tests can also lead to further necessary software analyses.

4.3.    Review of testing modalities and evaluation strategies

The testing modalities (introduced in paragraph 4.2), the thresholds recommended to trigger investigations (4.2.3.1) and/or the emissions data obtained for various modalities and which may be used for the relative analysis (4.2.3.2) should not be kept fixed but will be subject to an annual review and update by the European Commission Joint Research Centre (JRC).

4.4.    Non-acceptable Auxiliary Emission Strategies (AES)

The AES included in the table 7 below are currently considered as non-acceptable by the Commission due to high increase in emissions or the existence of better technologies to avoid damage. In line with the recent Court judgements the manufacturer is under the obligation to apply technical devices capable of complying with the limits of Regulation (EU) 2017/1151 (29) and the need for a defeat device could only exist, where at the time of type approval no other technical solution made it possible to avoid immediate risks of damage or accident to the engine (30). Further evidence can be found in Annex IV.

Only with appropriate substantiation of the necessity according to the methodologies described in Regulation (EU) 2017/1151 or Regulation (EU) No 582/2011 and in exceptional cases only, can the AES in this list be considered appropriate by the Type Approval Authority.

It is expected that this list will be further updated with new cases as these appear, taking into account the technical information provided by national authorities as derived from their own experience and in order to reflect technical progress.

Table 7

Examples of non-acceptable AES  (33)

AES	Observed behaviour
EGR or emissions control reduced or deactivated beyond what is described (31) in the BES upon hot engine start	Higher emissions in hot start than in cold start
EGR reduced or deactivated beyond what is described (31) in the BES at ambient temperatures above -4 °C (32)	Higher emissions at the lower end of ‘thermal window’ where EGR rate might decrease in order to avoid condensation and/or sooting
EGR reduced or deactivated beyond what is described (31) in the BES at high ambient temperatures	Higher emissions at the higher end of ‘thermal window’ where EGR rate might decrease in order to avoid overheating of the engine
Parameters that are not directly linked with a physical phenomenon that might require the use of an AES, such as timer, RPM, vehicle speed, engine torque, fuel consumption, etc…	Using a proxy that is not directly linked with a natural phenomenon (i.e. high vehicle speed, or ambient temperature used to reduce the efficiency of an EGR or SCR system, or turn-off EGR in order to avoid condensation)
Reactant dosing modification during the inducement period	The reactant (AdBlue) dosing is diminished or stopped during the inducement period resulting in higher emissions than during the BES without any plausible justification
Gasoline fuel enrichment	Fuel enrichment which may be used for overheating protection at high engine speed. This results in increased CO emissions under dynamic driving conditions.

PART B: Anti-tampering protection

5.   Odometer and emission control systems tampering protection

Tampering (34) of emission control systems with the goal to remove them or modify their use and worsen the emission performance of the vehicle is expressly prohibited under the current regulations (35) .

Article 3, point 4 and 5 and Annex I, Section 2.3 on provisions for electronic system security of Regulation (EU) 2017/1151 further requires that manufacturers install systems to deter modification of emission control systems and the odometer in light duty vehicles. Similar provisions are included in Regulation (EU) No 582/2011, Article 3, point 8 and Annex X, point 2.1 for heavy duty vehicles.

Ample evidence has shown that tampering of emission control systems happens in all types of motor vehicles (36) , (37) , (38). The most evident reason for this practice has been the economic gain for the vehicle user that does not have to pay for the reagent or substitute a faulty particle filter, other reasons are the increase of power or the reduction of fuel consumption. Similar tampering occurs regularly also for odometer (39) , (40) , (41) , (42) also for economic gain by artificially presenting a vehicle as newer. A JRC report on ‘Vehicles Odometer and Emission Control Systems: Digital Tampering and Countermeasures’ (43) detailed possible ways forward to eliminate digital tampering which are in need of further development. It is therefore important that the correct application of the anti-tampering measures taken by the manufacturers are already checked during market surveillance with simple tests.

5.1.    Proposed methodology for checking compliance with anti-tampering requirements 28

Methodology for emission control systems

In order to confirm that appropriate anti-tampering protection against manipulation of the emission control systems is installed by the manufacturer, it is important that the laboratory attempts to perform a manipulation of the emission control system, by using at least one of the systems for tampering of emission controls available in the market for each vehicle tested.

If the manipulation is feasible then the vehicle does not comply with the security of electronic systems provision required in Regulation (EU) 2017/1151 or Regulation (EU) No 582/2011, since the vehicle can be tampered with.

The market surveillance authorities should attempt to use different systems (such as AdBlue killers, removal of DPFs, EGR and TWC physical and electronic tampering, etc.) for tampering emission controls to address all possible tampering possibilities, each year. It is appropriate to include the findings in ICSMS, publish them and discuss them in the Forum and make them public.

Alternatively, the laboratory may develop its own appropriate checks for testing that the emission control systems are adequately protected, such as software analysis, or other more complex system security checks.

Methodology for odometer tampering

In order to confirm that appropriate anti-tampering protection against manipulation of the odometer is installed by the manufacturer, it is best practice for the laboratory to attempt to perform a manipulation of the odometer, by using one of the relevant tools available in the market. If the manipulation is successful then the vehicle does not comply with the security of electronic systems provision as required in Regulation (EU) 2017/1151, and should be recalled for a software update eliminating the weakness allowing the tampering.

Market surveillance authorities should report the findings in ICSMS (44), and discuss them in the Forum. Such reports should be made public.

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(1)  OJ L 171, 29.6.2007, p. 1.

(2)  OJ L 188, 18.7.2009, p. 1.

(3)  OJ L 175, 7.7.2017, p. 1.

(4)  OJ L 167, 25.6.2011, p. 1.

(5)  Paragraph 112 of the judgement in Case C-693/18.

(6)  Point 2 of the Judgements in cases C 128/20, C 134/20 and C 145/20 of 14 July 2022.

(7)  Commission Notice on Guidance on the evaluation of Auxiliary Emission Strategies and the presence of Defeat Devices with regard to the application of Regulation (EC) No 715/2007 on type approval of motor vehicles with respect to emissions from light passenger and commercial vehicles (Euro 5 and Euro 6), C(2017) 352 final.

(8)  OJ L 171, 24.6.2013, p. 1.

(9)  Part a according to Regulation (EU) No 582/2011 amended by Regulation (EU) No 133/2014, Annex VI point 4.

(10)  Article 7 (3) of Regulation EU 2018/858.

(11)  OJ L 151, 14.6.2018, p. 1.

(12)  Article 8 (1) of Regulation EU 2018/858.

(13)  CARES | City Air Remote Emission Sensing (cares-project.eu)

(14)  Project | Nemo (nemo-cities.eu)

(15)  For Light-Duty Vehicles, according to Article 9 of Regulation (EU) 2017/1151 in conjunction with Appendix 1 of Annex II to that Regulation.

For Heavy-Duty Engines, according to Article 12 Regulation (EU) No 582/2011 in conjunction with Annex II to that Regulation.

(16)  The table is non-exhaustive. It shall be interpreted depending on the specific conditions relating to a specific type approval character.

(17)  https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A42019X0253&qid=1658915552410

(18)  In this case, the PEMS test is sufficient to demonstrate the engine compliance with the WHTC requirements and the extraction of the engine can be avoided.

(19)  Note that even in that case, the emissions would still need to respect the limits.

(20)  CADC: Common Artemis Driving Cycles.

(21)  BAB: ADAC Highway Cycle (BAB 130).

(22)  TfL : Transport for London Cycle.

(23)  Having at least a minimum distance of 16 km but not compliant for other requirements.

(24)  Nota Bene: The proposed list of modalities is not exhaustive and the exact testing condition will depend on the driving situations encountered in real life.

(25)  The three phases of the test are: U is for Urban, R is for Rural and M is for Motorway.

(26)  The applicable emissions limits for on-road emissions tests includes the additional margins to account for the PEMS measurement uncertainty as prescribed in the relevant Regulations.

(27)  such as preventive maintenance or a flow sensor to avoid and detect EGR fouling.

(28)  Joint Research Centre 2019 light-duty vehicles emissions testing - https://ec.europa.eu/jrc/en/publication/eur-scientific-and-technical-research-reports/joint-research-centre-2019-light-duty-vehicles-emissions-testing.

(29)  See para 79 in case C-134/20.

(30)  See para 69 in case C-128/20.

(31)  As described in the Extended Documentation Package.

(32)  As long as it is not compensated by other emissions control system/s.

(33)  For type approvals granted following the publication of this document.

(34)  ‘tampering’ means inactivation, adjustment or modification of the vehicle emissions control or propulsion system, including any software or other logical control elements of those systems, that has the effect, whether intended or not, of worsening the emissions performance of the vehicle.

(35)  Article 7 of Regulation (EC) No 595/2009.

(36)  Status Report from Swiss heavy-duty truck controls, Informal document GRPE-75-06, June 2017.

(37)  ACEA Adblue Emulator Workshop, 5 Dec 2017.

(38)  Investigation of NOx manipulation in heavy-duty vehicles, Danish Road Safety Agency, 2018.

(39)  Research for TRAN Committee – Odometer tampering: measures to prevent it. Study 2017.

(40)  https://www.fiaregion1.com/mileage-fraud/

(41)  https://unece.org/DAM/trans/doc/2015/wp29grsg/GRSG-108-37e.pdf

(42)  Tachomanipulation bei Gebrauchtwagen erkennen | ADAC

(43)  https://circabc.europa.eu/d/a/workspace/SpacesStore/079d3ad8-7121-4c8b-bb57-f5ba13c4407c/JRC%20Vehicles%20Odometer%20and%20Emission%20Control%20System%20Digital%20Tampering.pdf

(44)  Article 12 (1) of Regulation EU 2018/858.