Fault diagnosis apparatus for fuel cell electric vehicle and method thereof

A fault diagnosis apparatus for a fuel cell electric vehicle and a method thereof are provided. The apparatus includes: a main relay connected to a fuel cell stack; a power converter connected to the main relay; one end of the heater relay is connected with the fuel cell stack and the main relay, and the other end of the heater relay is connected with a cathode oxygen consumption (COD) heater; and a fuel cell control unit (FCU) connected with the main relay, the power converter, and the heater relay. When the vehicle enters a shutdown procedure, the FCU diagnoses a failure of the main relay based on a change amount of a stack voltage according to which the heater relay is controlled to be turned off and turned on, and a power of the power converter according to variable control of a voltage of the power converter, and outputs a diagnosis result. 提供了用于燃料电池电动车辆的故障诊断装置及其方法。该装置包括：主继电器，连接到燃料电池堆；功率转换器，连接到主继电器；加热器继电器，一端连接燃料电池堆和主继电器，且另一端连接阴极氧消耗(COD)加热器；以及燃料电池控制单元(FCU)，与主继电器、功率转换器和加热器继电器相连。当车辆进入关闭程序时，FCU基于根据控制加热器继电器断开