Cause : EPROM fault comes when  a malfunction within the Control Unit's (CU) Electrically Erasable Programmable Read-Only Memory (EEPROM). The EEPROM is a crucial component that stores essential configuration data and parameters for the drive's operation.

The FF05 fault in siemens master drive indicate EPROM fault. This code indicates a critical hardware or software malfunction within the Control Unit (CU) that halts drive operation.