16.1.2023
EN
Official Journal of the European Union
L 14/303
The items of Appendix 3 to this annex list the systems or components required to be monitored by the OBD system and describes the types of monitoring expected for each of these components or systems (i.e. emission threshold monitoring, performance monitoring, total functional failure monitoring, or component monitoring).
The manufacturer can decide to monitor additional systems and components.
4.2.1.
Selection of the monitoring technique Approval authorities may approve a manufacturer's use of another type of monitoring technique than the one mentioned in Appendix 3 or, in the case of dual-fuel engines or vehicles in section 7. of Annex 15.
The chosen type of monitoring shall be shown by the manufacturer, to be robust, timely and efficient (i.e. through technical considerations, test results, previous agreements, etc.).
In case a system and/or component is not covered by Appendix 3 or, in the case of dual-fuel engines or vehicles in section 7. of Annex 15, the manufacturer shall submit for approval to the Type Approval Authority an approach to monitoring.
The Type Approval Authority will approve the chosen type of monitoring and monitoring technique (i.e. emission threshold monitoring, performance monitoring, total functional failure monitoring, or component monitoring) if it has been shown by the manufacturer by reference to those detailed in Appendix 3 or, in the case of dual- fuel engines or vehicles in section 7. of Annex 15, to be robust, timely and efficient (i.e. through either technical considerations, test results, previous agreements, etc.).
4.2.1.1.
Correlation to actual emissions In the case of emission threshold monitoring, a correlation to test-cycle specific emissions shall be required.
This correlation would typically be demonstrated on a test engine in a laboratory setting.
In all other monitoring cases (i.e. performance monitoring, total functional failure monitoring, or component monitoring), no correlation to actual emissions is necessary.
However, the Type Approval Authority may request test data to verify the classification of the malfunction effects as described in paragraph 6.2. of this annex.
Examples: An electrical malfunction may not require a correlation because this is a yes/no malfunction.
A DPF malfunction monitored via delta pressure may not require a correlation because it anticipates a malfunction.
If the manufacturer demonstrates, according to the demonstration requirements of this annex, that emissions would not exceed the OBD threshold limits upon total failure or removal of a component or system, a performance monitoring of this component or system shall be accepted.
When a tailpipe emission sensor is used for monitoring the emissions of a specific pollutant all other monitors may be exempted from further correlation to the actual emissions of that pollutant.
Nevertheless, such exemption shall not preclude the need to include these monitors, using other monitoring techniques, as part of the OBD system as the monitors are still needed for the purpose of malfunction isolation.
A malfunction shall always be classified according to paragraph 4.5. based on its impact on emissions, regardless of the type of monitoring used to detect the malfunction.
4.2.2.
Component monitoring (input/output components/systems) In the case of input components that belong to the engine system, the OBD system shall at a minimum detect electrical circuit failures and, where feasible, rationality failures.
The rationality failure diagnostics shall then verify that a sensor output is neither inappropriately high nor inappropriately low (i.e. there shall be "two-sided" diagnostics).