On certain trucks, the air supply line to the horn may not have a protective wrap and could become damaged by heat from the exhaust pipe. If this happens, a leak may develop and cause low air pressure. If you continue to ignore low air pressure warnings, the parking brakes could apply suddenly while driving.
Parking brakes that self-apply while driving could increase the risk of a crash.
Hino will notify owners by mail and instruct you to take your truck to a dealership to replace the air horn supply line assembly.