This paper deals with on-line software fault detection and isolation method for a drive composed of a fourleg inverter and a three-phase permanent magnet synchronous machine. The considered faults are single-phase open-circuit and current sensor outage. The method is based on the monitoring of the abc currents with phase-locked loops and the 'CUSUM' algorithm for the decision system. The impact of the considered faults is examined: first, in case there is no modification of the control and then in case a control reconfiguration is performed taking into account the fault diagnosis. Closed-loop operation is performed before, during and after the fault. Experimental results show that the latter case allows maintaining the drive in safe operation.