Abstract: A fuel cell system comprises a fuel cell having an anode flow path extending through the fuel cell between an anode inlet and an anode outlet, and a cathode flow path extending through the fuel cell between a cathode inlet and a cathode outlet. An anode purge valve is coupled to the anode outlet and has an outlet coupled to the cathode inlet. A purge valve controller is configured to effect a purge cycle by opening and closing the anode purge valve and to monitor a fuel cell voltage profile during the purge cycle to determine an operational state of the anode purge valve. A fuel cell voltage drop during a period following a command signal instructing opening of the anode purge valve is used to indicate successful start of a purge cycle. A fuel cell voltage rise during a period following a command signal instructing closing of the anode purge valve is used to indicate a successful end to a purge cycle.