Abstract: To address the problem of the fault code C019 of Vital Digital I/O Unit (VDX) of CTCS3-300T On-board ATP system in the maintenance, this paper analyzes the fault causes and function of VDX, and proposes the method of judging and dealing with this kind of fault to quickly and accurately locate the fault code C019 and puts forward a solution, so that the maintenance of VDX of on-board ATP system can be more rapid and effective.

Key words: CTCS3-300T, on-board equipment, VDX, C019 fault code

摘要： 针对CTCS3-300T车载设备安全数字量输入输出单元（VDX），指出在维护工作中出现的C019故障代码，通过对VDX的功能及自检原理介绍，提出判断和处理此类故障的方法，以便能快速准确定位C019故障代码的具体位置及解决方法，使车载ATP系统VDX的维护更快速有效。

关键词: CTCS3-300T, 车载设备, VDX, C019故障代码