A system and method for monitoring a circuit for impending failure includes measuring changes to frequency-domain impedance with a pair of analog-to-digital converters connected to a conductor while powering up, with or without interposing a series sense resistor for measuring applied current. Changes to frequency-domain impedance or power delivery voltage ratio are identified via a neural network trained to identify frequency-domain impedance associated with normal system behavior and general system failure mode. The neural network may be further trained to produce a predictive probability of specific failure mode types.