Abstract: A gas detection system. The gas detection system comprises a passive electrochemical (EC) gas sensor, a signal generator electrically coupled to the passive EC gas sensor, a low-pass filter electrically coupled to an output of the passive EC gas sensor, where the low-pass filter has a cut-off frequency below the fundamental frequency of an output of the signal generator, a high-pass filter electrically coupled to the output of the passive EC gas sensor, where the high-pass filter has a cut-off frequency below the fundamental frequency of the signal generator output, a fail indicator that activates when the gas detection system is powered and an amplitude of an output of the high-pass filter is below a first threshold, and a gas detected indicator that activates when the gas detection system is powered and an amplitude of an output of the low-pass filter is above a second configured threshold.