Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p45
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 45/150)
Character Range: 839911–842779

warm-up cycles or 200 engine operating hours, whichever occurs first. The OBD system shall erase all the DTCs and the applicable information (inclusive the associated freeze frame) upon request of a scan tool or a maintenance tool.
4.5. Requirements for malfunction classification
 Malfunction classification specifies the class to which a malfunction is assigned, when such a malfunction is detected according to the requirements of paragraph 4.2. of this annex.
 A malfunction shall be assigned to one class for the actual life of the vehicle unless the authority that granted the certificate or the manufacturer determines that reclassification of that malfunction is necessary.
 If a malfunction would result in a different classification for different regulated pollutant emissions or for its impact on other monitoring capability, the malfunction shall be assigned to the class that takes precedence in the discriminatory display strategy (for example Class A takes precedence over Class B1).
 If an MECS is activated as a result of the detection of a malfunction, this malfunction shall be classified based on either the emission impact of the activated MECS or its impact on other monitoring capability. The malfunction shall then be assigned to the class that takes precedence in the discriminatory display strategy.
4.5.1. Class A malfunction
 A malfunction shall be identified as Class A when the relevant OBD threshold limits (OTLs) are assumed to be exceeded.
 The emissions may still remain below the OTLs when this class of malfunction occurs.
4.5.2. Class B1 malfunction
 A malfunction shall be identified as Class B1 where circumstances exist that have the potential to lead to emissions being above the OTLs but for which the exact influence on emission cannot be estimated and thus the actual emissions according to circumstances may be above or below the OTLs.
 Examples of Class B1 malfunctions may include malfunctions detected by monitors that infer emission levels based on readings of sensors or restricted monitoring capability.
 Class B1 malfunctions shall include malfunctions that restrict the ability of the OBD system to carry out monitoring of Class A or B1 malfunctions.
4.5.3. Class B2 malfunction
 A malfunction shall be identified as Class B2 when circumstances exist that are assumed to influence emissions but not to a level that exceeds the OTL.
 Malfunctions that restrict the ability of the OBD system to carry out monitoring of Class B2 malfunctions of shall be classified into Class B1 or B2.
4.5.4. Class C malfunction
 A malfunction shall be identified as Class C when circumstances exist that, if monitored, are assumed to influence emissions but to a level that would not exceed the regulated emission limits.
 Malfunctions that restrict the ability of the OBD system to carry out monitoring of Class C malfunctions shall