Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p74
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 74/150)
Character Range: 919367–923310

commanded EGR flow rate (for example, because of the correct functioning of an SCR system downstream of the engine), then:
           1. Where the control of the EGR flow rate is performed by means of a closed-loop system, the OBD system shall detect a malfunction when the EGR system cannot increase the EGR flow to achieve the demanded flow rate.
            Such a malfunction shall not be classified as a Class C failure.
           2. Where the control of the EGR flow rate is performed by means of an open-loop system, the OBD system shall detect a malfunction when the system has no detectable amount of EGR flow when EGR flow is expected.
            Such a malfunction shall not be classified as a Class C failure.
           (c2) EGR cooler under cooling performance ( total functional failure monitoring)
       In the case where total failure of the EGR cooler system's ability to achieve the manufacturer's specified cooling performance would not result in the monitoring system detecting a failure (because the resulting increase in emissions would not reach the OBD threshold limit for any pollutant), the OBD system shall detect a malfunction when the system has no detectable amount of EGR cooling.
       Such a malfunction shall not be classified as a Class C failure.
       Appendix 3 - Item 7
       Fuel System monitoring
       The OBD system shall monitor the following elements of the fuel system on engines so-equipped for proper operation:
                                                                                                                                                                                                                                                                                                                     Diesel      Gas
(a) Fuel system pressure control: fuel system ability to achieve the commanded fuel pressure in closed loop control - performance monitoring.                                                                                                                                                                        X
(b) Fuel system pressure control: fuel system ability to achieve the commanded fuel pressure in closed loop control in the case where the system is so constructed that the pressure can be controlled independently of other parameters - performance monitoring.                                                   X
(c) Fuel injection timing: fuel system ability to achieve the commanded fuel timing for at least one of the injection events when the engine is equipped with the appropriate sensors - performance monitoring.                                                                                                      X
(d) Fuel injection quantity: fuel system ability to achieve the commanded fuel quantity by detecting errors from desired fuel quantity in at least one of the injection events when the engine is equipped with the appropriate sensors (e.g. in pre- main- or post-injection) – emission threshold monitoring.      X
(e) Fuel injection system: ability to maintain the desired air-fuel ratio (incl. but not limited to self-adaptation features) – performance monitoring.                                                                                                                                                                          X

       Appendix 3 - Item 8
       Air handling and turbocharger/Boost pressure control system
       The OBD system shall monitor the following elements of the Air handling and turbocharger/Boost pressure control system on engines so-equipped for proper operation:
                                                                                                                                                                                                                                  Diesel      Gas
(a1) Turbo under/over boost: turbo boost system's ability to maintain the