Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p46
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 46/150)
Character Range: 842525–845701

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 be classified into Class B1 or B2.
4.6. Alert system
 The failure of a component of the alert system shall not cause the OBD system to stop functioning.
4.6.1. MI specification
 The malfunction indicator shall be a visual signal that is perceptible under all lighting conditions. The malfunction indicator shall comprise a yellow or amber (as defined in UN/ECE Regulation No. 37) warning signal identified by the 0640 symbol in accordance with ISO Standard 7000:2004.
4.6.2. MI illumination schemes
 Depending on the malfunction(s) detected by the OBD system, the MI shall be illuminated according to one of the activation modes described in the following table:
                          Activation mode 1            Activation mode 2                Activation mode 3                     Activation mode 4
Conditions of activation  No malfunction               Class C malfunction              Class B malfunction and B1 counters   Class A malfunction or B1 counter
                                                                                        < 200 h                               > 200 h
Key on engine on          No display                   Discriminatory display strategy  Discriminatory display strategy       Discriminatory display strategy
Key on engine off         Harmonized display strategy  Harmonized display strategy      Harmonized display strategy           Harmonized display strategy

 The display strategy requires the MI to be activated according to the class in which a malfunction has been classified. This strategy shall be locked by software coding that shall not be routinely available via the scan tool.
 The MI activation strategy at key on, engine off is described in paragraph 4.6.4.
 Figures B1 and B2 illustrate the prescribed activation strategies at key on, engine on or off.
  Figure B1
  Bulb test and readiness indication

  Figure B.2
  Malfunction display strategy: only the discriminatory strategy is applicable

4.6.3. MI activation at "engine on"
 When the key is placed in the on position and the engine is started (engine on), the MI shall be commanded off unless the provisions of paragraph 4.6.3.1. have been met.
4.6.3.1. MI display strategy
 For the purpose of activating the MI, continuous-MI shall take precedence to short-MI and on-demand-MI. For the purpose of activating the MI, short-MI shall take precedence to on-demand-MI.
4.6.3.1.1. Class A malfunctions
 The OBD system shall command a continuous-MI upon storage of a confirmed DTC associated with a Class A malfunction.
4.6.3.1.2. Class B malfunctions
 The OBD system shall command a "short-MI" at the next key-on event following storage of a confirmed and active DTC associated with a Class B malfunction.
 Whenever a B1 counter reaches 200 hours, the OBD system shall command a continuous-MI.
4.6.3.1.3. Class C malfunctions
 The manufacturer may make available information on Class C malfunctions