1. A method for detecting vehicle system faults, the method comprising: receiving, with a processor, a plurality of sensor signals from one or more sensors; thresholding, with the processor, the plurality of sensor signals for each respective sensor substantially in real time; and generating, with the processor, abnormal derivative frequency values for each of the plurality of thresholded sensor signals in real time and determining an operational status of at least each of the one or more sensors based on the abnormal derivative frequency values.