Systems and methods for detecting a blocked air discharge line of an air compressor are described, which include monitoring motor current (IMTR) drawn by a compressor motor (14), and calculating a three-point moving average for a steady state current drawn by the compressor motor (14) upon the motor reaching steady state (nominal) operating speed. A current threshold (IMTR_LIMIT) (28) is calculated as a function of the three-point moving average, and a determination is made regarding whether a current drawn by the compressor motor (14) has exceeded the current threshold (28) and is consistent with a current profile (34) indicative of a blocked air line (15). If a blocked air line is detected, a compressor shut-off command is generated and transmitted to the compressor motor (14) to shut the compressor motor off prior to opening of a safety valve (21) on the compressor (12).