• Code: 857
• Description: USB I/F Error
  USB interface error detected.
• Causes: - Defective controller

• Code: 900
• Description: Electrical total counter error
  The electrical total counter does not work properly.
• Causes: - NVRAM on the GDI controller board defective

• Code: 901
• Description: Mechanical total counter
  The mechanical total counter does not work properly.
• Causes: - Mechanical total counter defective
  - BICU defective
  - Disconnected mechanical total counter

• Code: 903
• Description: Engine total counter error
  The checksum of the total counter is not correct.
• Causes: - NVRAM on the BICU defective

• Code: 920
• Description: Printer error
  A fatal error is detected in the printer application program
• Causes: - Printer application program defective
  - Hardware configuration incorrect (including memory shortage)

• Code: 921
• Description: Printer font error
  Necessary font files are not found.
• Causes: - Font file not installed

• Code: 928
• Description: Memory error
  The machine detects a discrepancy in the write/read data during its write/read test (done at power off/on and at recovery from low power or night/off mode).
• Causes: - Memory defective
  - BICU defective
  - Poor connection between BICU and memory

• Code: 954
• Description: Printer application program error
  The printer status does not become ready when the printer application program is necessary for image processing.
• Causes: - Application program defective