A system is provided including at least one pump for pumping a fluid into a wellbore, a pressure sensor provided at a wellhead of the wellbore for measuring a backpressure of the fluid being pumped into the wellbore, and a diagnostic manager. The diagnostic manager obtains pressure data associated with a pressure signal from the pressure sensor, wherein the pressure data includes pressure measurements of the fluid over a selected time period. The diagnostic manager converts, based on the pressure data, at least a portion of the pressure signal into frequency domain. The diagnostic manager detects a change in frequency of the pressure signal in the Fourier spectrum and determines that a fault associated with the wellbore has occurred based on the changed frequency of the pressure signal.