Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:13:p19
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 13 (pt 19/23)
Character Range: 1996499–1999764

have been implemented by the manufacturer, have been encountered. The numerator shall not be incremented more than once per driving cycle, unless there is reasoned technical justification.

              7.3. DenominatorM

              7.3.1. The purpose of the denominator is to provide a counter indicating the number of vehicle driving events, taking into account special conditions for a specific monitor. The denominator shall be incremented at least once per driving cycle, if during this driving cycle such conditions are met and the general denominator is incremented as specified in paragraph 7.5. of this appendix unless the denominator is disabled according to paragraph 7.7. of this appendix.

              7.3.2. In addition to the requirements of paragraph 7.3.1. of this appendix:

                   (a) Secondary air system monitor denominator(s) shall be incremented if the commanded "on" operation of the secondary air system occurs for a time greater than or equal to 10 seconds. For purposes of determining this commanded "on" time, the OBD system may not include time during intrusive operation of the secondary air system solely for the purposes of monitoring.

                   (b) Denominators of monitors of systems only active during cold start shall be incremented if the component or strategy is commanded "on" for a time greater than or equal to 10 seconds.

                   (c) The denominator(s) for monitors of Variable Valve Timing (VVT) and/or control systems shall be incremented if the component is commanded to function (e.g., commanded "on", "open", "closed", "locked", etc.) on two or more occasions during the driving cycle or for a time greater than or equal to 10 seconds, whichever occurs first.

                   (d) For the following monitors, the denominator(s) shall be incremented by one if, in addition to meeting the requirements of this paragraph on at least one driving cycle, at least 800 cumulative kilometres of vehicle operation have been experienced since the last time the denominator was incremented:

                     (i) Diesel oxidation catalyst;

                     (ii) Diesel particulate filter.

                   (e) Without prejudice to requirements for the increment of denominators of other monitors the denominators of monitors of the following components shall be incremented if and only if the driving cycle started with a cold start:

                     (i) Liquid (oil, engine coolant, fuel, SCR reagent) temperature sensors;

                      (ii) Clean air (ambient air, intake air, charge air, inlet manifold) temperature sensors;

                      (iii) Exhaust (EGR recirculation/cooling, exhaust gas turbo-charging, catalyst) temperature sensors;

                   (f) The denominators of monitors of the boost pressure control system shall be incremented if all of the following conditions are met:

                     (i) The general denominator conditions arc fulfilled;

                     (ii) The boost pressure control system is active for a time greater than or equal to 15 seconds.

                  (g) Manufacturers may request to use special denominator conditions for certain components or systems and this request can be approved only