• Code: C2256
• Description: Developing motor’s turning at abnormal timing
  The motor lock signal remains LOW for a predetermined continuous period of time while the motor remains stationary.
• Remedy: 1 Check the connector between M21-PRCB CN32 for proper connection and correct as necessary. 2 Check the M21 connector for proper drive coupling and correct as necessary. 3 M21 operation check PRCB CN32-2 (REM) PRCB CN32-5 (LOCK) bizhub C554 19-J bizhub C454 17-J. 4 Replace M21. 5 Replace PRCB.

• Code: C2350
• Description: Toner suction fan's failure to turn
  The fan lock signal remains HIGH for a predetermined continuous period of time while the fan is turning.
• Remedy: 1 Check the connectors between FM11-relay CN62- PRCB CN23 for proper connection, and correct as necessary. 2 Check the fan for possible overload and correct as necessary. 3 FM11 operation check PRCB CN23-10 (REM) 5-C. 4 Replace FM11. 5 Replace PRCB.

• Code: C2355
• Description: Transfer belt cleaner cooling fan motor’s failure to turn
  The fan lock signal remains HIGH for a predetermined continuous period of time while the fan is turning.
• Remedy: 1 Check the connector between FM2-relay CN115- PRCB CN13 for proper connection and correct as necessary. 2 Check the fan for possible overload and correct as necessary. 3 FM2 operation check PRCB CN13-8 (REM) PRCB CN13-10 (LOCK) bizhub C554 23-C bizhub C454 25-C. 4 Replace FM2. 5 PRCB ICP3 conduction check. 6 Replace PRCB.

• Code: C2411
• Description: Developing unit/C new article release
  The status with the new unit is not cleared after the new developing unit is set.
• Remedy: 1 Reinstall developing unit. 2 Check the connector between developing unit-FRB CN13, CN14, CN15, CN16 for proper connection and correct as necessary. 3 Check the connector between FRB CN1, CN3-PRCB CN7, CN9 for proper connection and correct as necessary. 4 Replace the developing unit. 5 Replace FRB. 6 Replace PRCB.

• Code: C2412
• Description: Developing unit/M new article release
  The status with the new unit is not cleared after the new developing unit is set.
• Remedy: 1 Reinstall developing unit. 2 Check the connector between developing unit-FRB CN13, CN14, CN15, CN16 for proper connection and correct as necessary. 3 Check the connector between FRB CN1, CN3-PRCB CN7, CN9 for proper connection and correct as necessary. 4 Replace the developing unit. 5 Replace FRB. 6 Replace PRCB.

• Code: C2413
• Description: Developing unit/Y new article release
  The status with the new unit is not cleared after the new developing unit is set.
• Remedy: 1 Reinstall developing unit. 2 Check the connector between developing unit-FRB CN13, CN14, CN15, CN16 for proper connection and correct as necessary. 3 Check the connector between FRB CN1, CN3-PRCB CN7, CN9 for proper connection and correct as necessary. 4 Replace the developing unit. 5 Replace FRB. 6 Replace PRCB.

• Code: C2414
• Description: Developing unit/K new article release
  The status with the new unit is not cleared after the new developing unit is set.
• Remedy: 1 Reinstall developing unit. 2 Check the connector between developing unit-FRB CN13, CN14, CN15, CN16 for proper connection and correct as necessary. 3 Check the connector between FRB CN1, CN3-PRCB CN7, CN9 for proper connection and correct as necessary. 4 Replace the developing unit. 5 Replace FRB. 6 Replace PRCB.

• Code: C2551
• Description: Abnormally low toner density detected cyan TCR sensor
  When sampling data is determined in TC ratio calculation control, TCR sensor output is higher than a predetermined value for a predetermined number of times in a row even though there is toner in the sub hopper
• Remedy: 1 Perform image troubleshooting procedure if image density is low. 2 Reinstall developing unit. 3 Reinstall toner cartridge. 4 Check the connector between developing unit-FRB CN13, CN14, CN15, CN16 for proper connection and correct as necessary. 5 Check the connector between FRB CN1, CN3-PRCB CN7, CN9 for proper connection and correct as necessary. 6 M10 operation check PRCB CN14-13 to 16 18-C. 7 M6, M7. M8, M9 operation check PRCB CN14-13 to 16 (M6) PRCB CN14-9 to 12 (M7) PRCB CN14-5 to 8 (M8) PRCB CN14-1 to 4 (M9) 17 to 18-C. 8 If the toner empty sensor and its surroundings inside the sub hopper are dirtied with toner, clean them. 9 Replace the developing unit. 10 Replace FRB. 11 PRCB ICP21, ICP40, ICP41, ICP44, ICP46 conduction check. 12 Replace PRCB.