Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:99:p14
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 99 (pt 14/39)
Character Range: 1191672–1194686

mode;

                  (b) Dual-fuel engines of Types 1B, 2B and 3B shall operate in diesel mode.

       4.2.3.1. Unavailability of gaseous fuel – empty gaseous fuel tank

              In the case of an empty gaseous fuel tank, the service mode or, as appropriate according to paragraph 4.2.3., the diesel mode shall be activated as soon as the engine system has detected that the tank is empty.

              When the gas availability in the tank again reaches the level that justified the activation of the empty tank warning system specified in paragraph 4.3.2., the service mode may be deactivated, or, when appropriate, the dual-fuel mode may be reactivated.

       4.2.3.2. Unavailability of gaseous fuel – malfunctioning gas supply

              In the case of a malfunctioning gas supply system according to paragraph 7.2., the service mode or, as appropriate according to paragraph 4.2.3., the diesel mode shall be activated when the DTC relevant to that malfunction has the confirmed and active status.

              As soon as the diagnostic system concludes that the malfunction is no longer present or when the information, including DTCs relative to the failures, justifying its activation is erased by a scan tool, the service mode may be deactivated, or, when appropriate, the dual-fuel mode may be reactivated.

              4.2.3.2.1. If the counter specified in paragraph 4.4. and associated with a malfunctioning gas supply system is not at zero, and is consequently indicating that the monitor has detected a situation when the malfunction may have occurred for a second or subsequent time, the service mode or, as appropriate, the diesel mode shall be activated when the DTC has the status "potential".

       4.2.3.3. Unavailability of gaseous fuel – abnormality of gas consumption

              In case of an abnormality of gas consumption in dual-fuel mode according to paragraph 7.3., the service mode or, as appropriate according to paragraph 4.2.3., the diesel mode shall be activated when the DTC relevant to that malfunction has reached the potential status.

              As soon as the diagnostic system concludes that the malfunction is no longer present or when the information, including DTCs relative to the failures, justifying its activation is erased by a scan tool, the service mode may be deactivated, or, when appropriate, the dual-fuel mode may be reactivated.

4.3. Dual-fuel indicators
              4.3.1. Dual-fuel operating mode indicator

              Dual-fuel engines and vehicles shall provide to the driver a visual indication of the mode under which the engine operates (dual-fuel mode, diesel mode, or service mode).

              The characteristics and the location of this indicator are left to the decision of the manufacturer and may be part of an already existing visual indication system.

              This indicator may be completed by a message display. The system used for displaying the messages referred to in this paragraph may be