Systems and methods are provided to detect a failed thermocouple. A temperature in a gas path of a gas turbine engine may be measured, where the temperature is based on a signal generated by a thermocouple during a startup of the gas turbine engine and/or during an idle period that immediately follows the startup, and the thermocouple protrudes into the gas path. A failure of the thermocouple may be detected if the temperature is determined to be less than a threshold temperature.