Commission Directive 2005/78/EC (repealed)Show full title

1. INTRODUCTION

This Appendix describes the procedure for checking the function of the on board diagnostic (OBD) system installed on the engine by failure simulation of relevant emission-related systems in the engine management or emission control system. It also sets procedures for determining the durability of OBD systems.

1.1. Deteriorated components/systems

In order to demonstrate the efficient monitoring of an emission control system or component, the failure of which may result in tailpipe emissions exceeding the appropriate OBD threshold limits, the manufacturer must make available the deteriorated components and/or electrical devices which would be used to simulate failures.

Such deteriorated components or devices must not cause emissions to exceed the OBD threshold limits referred to in the table in Article 4(3) of this Directive by more than 20 %.

In the case of type-approval of an OBD system according to Article 4(1) of this Directive, the emissions shall be measured over the ESC test cycle (see Appendix 1 to Annex III to Directive 2005/55/EC). In the case of type-approval of an OBD system according to Article 4(2) of this Directive, the emissions shall be measured over the ETC test cycle (see Appendix 2 to Annex III to Directive 2005/55/EC).

1.1.1. If it is determined that the installation of a deteriorated component or device on an engine means that a comparison with the OBD threshold limits is not possible (e.g. because the statistical conditions for validating the ETC test cycle are not met), the failure of that component or device may be considered as qualified upon the agreement of the type-approval authority based on technical argumentation provided by the manufacturer.

1.1.2. In the case that the installation of a deteriorated component or device on an engine means that the full load curve (as determined with a correctly operating engine) cannot (even partially) be attained during the test, the deteriorated component or device is considered as qualified upon the agreement of the type-approval authority based on technical argumentation provided by the manufacturer.

1.1.3. The use of deteriorated components or devices that cause engine emissions to exceed the OBD threshold limits referred to in the table in Article 4(3) of this Directive by no more than 20 % may not be required in some very specific cases (for example, if a limp home strategy is activated, if the engine cannot run any test, or in case of EGR sticking valves, etc). This exception shall be documented by the manufacturer. It is subject to the agreement of the technical service.

1.2. Test principle

When the engine is tested with the deteriorated component or device fitted, the OBD system is approved if the MI is activated. The OBD system is also approved if the MI is activated below the OBD threshold limits.

The use of deteriorated components or devices that cause the engine emissions to exceed the OBD threshold limits referred to in the table in Article 4(3) of this Directive by no more than 20 % are not required in the specific case of the failure modes described in sections 6.3.1.6 and 6.3.1.7 of this Appendix and also with respect to monitoring for major functional failure.

1.2.1. The use of deteriorated components or devices that cause engine emissions to exceed the OBD threshold limits referred to in the table in Article 4(3) of this Directive by no more than 20 % may not be required in some very specific cases (for example, if a limp home strategy is activated, if the engine cannot run any test, or in case of EGR sticking valves, etc). This exception shall be documented by the manufacturer. It is subject to the agreement of the technical service.