A method of detecting and isolating a fault in an electric motor system having a motor drive electronics component that is configured to drive an electric motor having a plurality of phases through harnessing, the method comprising: detecting, with the motor drive electronics component, the fault in the electric motor system; applying a known excitation, at the MDE component, according to a selected gate switching sequence for a first phase and a second phase of the plurality of phases of the electric motor in a first direction; sensing a phase current value of the MDE component for each phase of plurality of phases of the electric motor associated with the applying; providing a known excitation, at the MDE component, according to a selected gate switching sequence for the first phase and the second phase of the plurality of phases of the electric motor system in an opposite direction of the first direction; measuring a phase current value in the MDE component for each phase of the electric motor associate with the providing; repeating the applying, sensing, providing and measuring for every possible combination of phases of the electric motor; and isolating the fault within the electric motor system based on the sensed and measured current values the method of detecting and isolating a fault characterized in that: wherein if the phase current values for each phase of the plurality of phases sensed matches the phase current values for each plurality of phases measured, it is indicative of at least one of an open phase of the electric motor and harness or a short in a winding of the electric motor and harness, and preferably wherein the fault is isolatable to either an open circuit fault of the electric motor or a short circuit of the electric motor and the fault is isolatable to a particular phase of the electric motor. detecting, with the motor drive electronics component, the fault in the electric motor system; applying a known excitation, at the MDE component, according to a selected gate switching sequence for a first phase and a second phase of the plurality of phases of the electric motor in a first direction; sensing a phase current value of the MDE component for each phase of plurality of phases of the electric motor associated with the applying; providing a known excitation, at the MDE component, according to a selected gate switching sequence for the first phase and the second phase of the plurality of phases of the electric motor system in an opposite direction of the first direction; measuring a phase current value in the MDE component for each phase of the electric motor associate with the providing; repeating the applying, sensing, providing and measuring for every possible combination of phases of the electric motor; and isolating the fault within the electric motor system based on the sensed and measured current values the method of detecting and isolating a fault characterized in that: wherein if the phase current values for each phase of the plurality of phases sensed matches the phase current values for each plurality of phases measured, it is indicative of at least one of an open phase of the electric motor and harness or a short in a winding of the electric motor and harness, and preferably wherein the fault is isolatable to either an open circuit fault of the electric motor or a short circuit of the electric motor and the fault is isolatable to a particular phase of the electric motor.