A fast short circuit detection method was presented. This method is based on the desaturation detection with gate-voltage monitoring for adaptive blanking. Based on simulations in LTspice, first measurements have shown a proper working of the enhanced desaturation detection method. Detailed investigations have shown false detections in some normal operating points. The most relevant influences for false detections in normal operating mode besides EMI noise are common source couplings, drain currents above the nominal value and the temperature of the GaN device. This paper presents the limits of the proposed short circuit detection method for proper working in detail.