FUEL CELL SYSTEM

A controller of a fuel cell system detects catalytic layer deterioration and drainage malfunction by the following inspection process. The controller may: execute drainage of water from a fuel cell, and acquire first/second output voltages of the fuel cell when an output current density of the fuel cell is a first reference current density A/A (A>A). When the first output voltage is lower than a first threshold voltage and the second output voltage is higher than a second threshold voltage, the controller may output a first determination signal indicating that the catalytic layer is deteriorated and the drainage is executed without malfunction. When the first output voltage is higher than the first threshold voltage and the second output voltage is lower than the second threshold voltage, the controller may output a second determination signal indicating that the catalytic layer is not deteriorated and the drainage is executed with malfunction.