Document ID: chunk:federal_register_of_legislation:F2021C00476:body:0:p45
Version: federal_register_of_legislation:F2021C00476
Segment Type: other
Provision Reference: 
Character Range: 125619–128590

provided by the sensor(s) of other wheel(s). 1/

          2.7.      "Full cycling" means that the anti-lock system is repeatedly modulating the brake force to prevent the directly controlled wheels from locking.  Brake applications where modulation only occurs once during the stop shall not be considered to meet this definition.

          3.   TYPES OF ANTI-LOCK SYSTEMS

          3.1.   A vehicle is deemed to be equipped with an anti-lock system within the meaning of paragraph 1. of Annex 5 to this Regulation, if one of the following systems is fitted:

          3.1.1.   Category 1 anti-lock system

             A vehicle equipped with a category 1 anti-lock system shall meet all the requirements of this annex.

          3.1.2.   Category 2 anti-lock system

             A vehicle equipped with a category 2 anti-lock system shall meet all the requirements of this annex, except those of paragraph 5.3.5.

          3.1.3.   Category 3 anti-lock system

             A vehicle equipped with a category 3 anti-lock system shall meet all the requirements of this annex, except those of paragraphs 5.3.4. and 5.3.5.  On such vehicles, any individual axle which does not include at least one directly controlled wheel must fulfil the conditions of adhesion utilization and the wheel-locking sequence of Annex 5 to this Regulation, instead of the adhesion utilization requirements prescribed in paragraph 5.2. of this annex.  However, if the relative positions of the adhesion utilization curves do not meet the requirements of paragraph 3.1. of Annex 5 to this Regulation, a check shall be made to ensure that the wheels on at least one of the rear axles do not lock before those of the front axle or axles under the conditions prescribed in paragraph 3.1. of Annex 5 to this Regulation, with regard to the braking rate and the load respectively.  These requirements may be checked on high- and low-adhesion road surfaces (about 0.8 and 0.3 maximum) by modulating the service braking control force.

          4.   GENERAL REQUIREMENTS

          4.1.   Any electrical failure or sensor anomaly that affects the system with respect to the functional and performance requirements in this annex, including those in the supply of electricity, the external wiring to the controller(s), the controller(s) 2/ and the modulator(s) shall be signalled to the driver by a specific optical warning signal.  The yellow warning signal specified in paragraph 5.2.21.1.2. of this Regulation shall be used for this purpose.

          4.1.1.   Sensor anomalies, which cannot be detected under static conditions, shall be detected not later than when the vehicle speed exceed 10 km/h 3/.  However, to prevent erroneous fault indication when a sensor is not generating a vehicle speed output, due to non-rotation of a wheel, verification may be delayed but detected not later than when the vehicle speed exceeds 15 km/h.

          4.1.2.   When the anti-lock braking system is