Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:13:p21
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 13 (pt 21/23)
Character Range: 2002210–2005408

OBD system shall report, in accordance with the ISO 15031-5 specifications of the standard listed in paragraph 6.5.3.2.(a) of this appendix, the ignition cycle counter and general denominator as well as separate numerators and denominators for the following monitors, if their presence on the vehicle is required by this annex:

              (a) Catalysts (each bank to be reported separately);

                  (b) Oxygen/exhaust gas sensors, including secondary oxygen sensors (each sensor to be reported separately);

              (c) Evaporative system;

              (d) EGR system;

              (e) VVT system;

              (f) Secondary air system;

              (g) Particulate filter;

                  (h) NOx after-treatment system (e.g. NOx adsorber, NOx reagent/catalyst system);

              (i) Boost pressure control system.
7.6.2. For specific components or systems that have multiple monitors, which are required to be reported by this point (e.g. oxygen sensor bank 1 may have multiple monitors for sensor response or other sensor characteristics), the OBD system shall separately track numerators and denominators for each of the specific monitors and report only the corresponding numerator and denominator for the specific monitor that has the lowest numerical ratio. If two or more specific monitors have identical ratios, the corresponding numerator and denominator for the specific monitor that has the highest denominator shall be reported for the specific component.
              7.6.2.1. Numerators and denominators for specific monitors of components or systems, that are monitoring continuously for short circuit or open circuit failures are exempted from reporting.

              "Continuously", if used in this context means monitoring is always enabled and sampling of the signal used for monitoring occurs at a rate no less than two samples per second and the presence or the absence of the failure relevant to that monitor has to be concluded within 15 seconds.

              If for control purposes, a computer input component is sampled less frequently, the signal of the component may instead be evaluated each time sampling occurs.

              It is not required to activate an output component/system for the sole purpose of monitoring that output component/system.

              7.6.3. All counters, when incremented, shall be incremented by an integer of one.

              7.6.4. The minimum value of each counter is 0, the maximum value shall not be less than 65,535, notwithstanding any other requirements on standardised storage and reporting of the OBD system.

              7.6.5. If either the numerator or denominator for a specific monitor reaches its maximum value, both counters for that specific monitor shall be divided by two before being incremented again according to the provisions set in paragraphs 7.2. and 7.3. of this appendix. If the ignition cycle counter or the general denominator reaches its maximum value, the respective counter shall change to zero at its next increment according to the provisions set in paragraphs 7.4. and 7.5. of this appendix, respectively.

              7.6.6. Each counter shall be