Division 5.2.3

When the supply voltage to the towed vehicle falls below a value nominated by the manufacturer at which the prescribed service braking performance can no longer be guaranteed, the separate yellow warning signal specified in point 2.2.1.29.2 of Annex I shall be activated via pin 5 of the ISO 7638:2003 connector. In addition, towed vehicles equipped with an electrical control line, when electrically connected to a tractor with an electric control line, shall provide the failure information for actuation of the warning signal specified in point 2.2.1.29.2.1 of Annex I via the data communication part of the electric control line.