In order to improve the reliability of motor system, this paper investigates the sensor-fault diagnosis methods for T-type inverter fed dual-three phase PMSM drives. Generally, a T-type three-level in-verter fed dual three-phase motor drive usually utilizes four phase-current sensors, two DC-link volt-age sensors and one speed sensors. A series of diagnostic methods have been comprehensively pro-posed for the three types of sensor faults. Both the sudden error change and gradual error change of sensor faults are considered. Firstly, the diagnosis of speed-sensor fault is achieved by monitoring the error between the rotating speed of stator flux and the value from speed sensor. Secondly, the large high-frequency voltage ripple of voltage difference between the estimated voltage and the reference voltage is used to identify the voltage-sensor faults and the faulty voltage sensor is determined ac-cording to the deviation of voltage difference. Thirdly, the abnormal current amplitude on harmonic subspace is adopted to identify the current-sensor faults and the faulty current sensor is located by distinguishing the current trajectory on harmonic subspace. The experiments have been taken on a laboratory prototype to verify the effectiveness of the proposed fault diagnosis schemes.