Document ID: chunk:federal_register_of_legislation:F2024C00356:reg:7:p14
Version: federal_register_of_legislation:F2024C00356
Segment Type: reg
Provision Reference: reg 7 (pt 14/51)
Character Range: 572337–575486

back to the previous state of activation during the first driving cycle on which the misfire level was detected and may be switched to the normal activated mode on subsequent driving cycles. If the MI is switched back to the previous state of activation, the corresponding fault codes and stored freeze-frame conditions may be erased.
              3.7.2. For all other malfunctions, the MI may be de-activated after three subsequent sequential driving cycles during which the monitoring system responsible for activating the MI ceases to detect the malfunction and if no other malfunction has been identified that would independently activate the MI.
              3.8.  Erasing a fault code
              3.8.1. The OBD system may erase a fault code and the distance travelled and freeze-frame information if the same fault is not re-registered in at least 40 engine warm-up cycles.
              3.9. Bi-fuelled gas vehicles
               In general, for bi-fuelled gas vehicles for each of the fuel types (petrol and (NG/biomethane)/LPG)) all the OBD requirements as for a mono-fuelled vehicle are applicable. To this end one of the following two options in paragraphs 3.9.1. or 3.9.2. or any combination thereof shall be used.
              3.9.1. One OBD system for both fuel types.
              3.9.1.1. The following procedures shall be executed for each diagnostic in a single OBD system for operation on petrol and on (NG/biomethane)/LPG, either independent of the fuel currently in use or fuel type specific:
               (a) Activation of malfunction indicator (MI) (see paragraph 3.5. of this  annex);
               (b) Fault code storage (see paragraph 3.6. of this annex);
               (c) Extinguishing the MI (see paragraph 3.7. of this annex);
               (d) Erasing a fault code (see paragraph 3.8. of this annex).
               For components or systems to be monitored, either separate diagnostics for each fuel type can be used or a common diagnostic.
              3.9.1.2. The OBD system can reside in either one or more computers.
              3.9.2. Two separate OBD systems, one for each fuel type.
              3.9.2.1. The following procedures shall be executed independently of each other when the vehicle is operated on petrol or on (NG/biomethane)/LPG:
               (a) Activation of malfunction indicator (MI) (see paragraph 3.5. of this  annex);
               (b) Fault code storage (see paragraph 3.6. of this annex);
               (c) Extinguishing the MI (see paragraph 3.7. of this annex);
               (d) Erasing a fault code (see paragraph 3.8. of this annex).
              3.9.2.2. The separate OBD systems can reside in either one or more computers.
              3.9.3. Specific requirements regarding the transmission of diagnostic signals from bi-fuelled gas vehicles.
              3.9.3.1. On a request from a diagnostic scan tool, the diagnostic signals shall be transmitted on one or more source addresses. The use of source addresses is described in ISO DIS 15031-5 "Road vehicles - communication between vehicles and external test equipment for emissions-related diagnostics –