Code Name Causes Possible Solutions UL5 Mechanical Weakening Detection 2 The drive detected undertorque as specified by the conditions for mechanical weakening detection set in L6-08 [Mechanical Fatigue Detect Select]. Examine the machine for deterioration. Note: Do a Fault Reset to clear the fault. If the drive detects this error, it will operate the motor as specified by the Stopping Method set in L6-08.