Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p75
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 75/150)
Character Range: 922781–926633

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 commanded boost pressure, detecting both "boost pressure too low" and "boost pressure too high" conditions – emission threshold monitoring.         X
(a2) Turbo under/over boost: turbo boost system's ability to maintain the commanded boost pressure, detecting both "boost pressure too low" and "boost pressure too high" conditions – performance monitoring.                            X
(a3) Turbo under boost: turbo boost system's ability to maintain the commanded boost pressure, detecting "boost pressure too low" conditions – total functional failure or performance monitoring as specified in this item.  X           X
(b) Variable Geometry Turbo (VGT) slow response: VGT system's ability to achieve the commanded geometry within a manufacturer specified time-performance monitoring.                                                          X           X
(c) Charge air cooling: Charge air cooling system efficiency - total functional failure.                                                                                                                                      X           X

           (a3) Turbo under boost (total functional failure monitoring)

           1. In the case where the emissions would not exceed the OBD threshold limits even upon total failure of the boost system's ability to maintain the demanded boost pressure and the control of the boost pressure is performed by means of a closed-loop system, the OBD system shall detect a malfunction when the boost system cannot increase the boost pressure to achieve the demanded boost pressure.
            Such a malfunction shall not be classified as a Class C failure.
           2. In the case where the emissions would not exceed the OBD threshold limits even upon total failure of the boost system's ability to maintain the demanded boost pressure and the control of the boost pressure is performed by means of an open-loop system, the OBD system shall detect a malfunction when the system has no detectable amount of boost pressure when boost pressure is expected.
       Such a malfunction shall not be classified as a Class C failure.
       Appendix 3 - Item 9
       Variable Valve Timing (VVT) System
       The OBD system shall monitor the following elements of the Variable Valve Timing (VVT) System on engines so-equipped for proper operation:
           (a) VVT target error: VVT system's ability to achieve the commanded valve timing - performance monitoring;
           (b) VVT slow response: VVT system's ability to achieve the commanded valve timing within a manufacturer specified time interval following the command-performance monitoring.
       Appendix 3 - Item 10
        Misfire Monitoring
                                                                                                                                                             Diesel  Gas
    (a) No prescriptions.                                                                                                                                    X
    (b) Misfire that may cause catalyst damage (e.g. by monitoring a certain percentage of misfiring in a certain period of time) – performance monitoring.          X

       Appendix 3 - Item 11
       Crankcase Ventilation System Monitoring
       No prescriptions.
       Appendix 3 - Item 12