Electric machines being the sole means of converting electrical energy to mechanical energy, advancement of hybrid electric vehicle technology and electric vehicle technology demands sophisticated motor controls. Inherent advantages of permanent magnet AC (PMAC) machines have made it one of the most preferable means of electromechanical energy conversion in a wide range of applications with the transportation industry (ground, sea and air) being a crucial area. Fault detection capabilities in transportation applications are crucial in guaranteeing safe and reliable operation. Increasing regulations require more safety features to be included in HEVs and EVs. Open phase fault diagnostic scheme presented in this paper reduces the burden on the Digital Signal Processor by eliminating RMS calculation of phase current with the means of an RMS generating analog circuit.