• Code: C2554
• Description: Abnormally high toner density detected magenta TCR sensor
  TC ratio in the developing unit, which is determined by toner replenishing amount control mechanism, is a predetermined value or more for a given number of times consecutively.
• Causes: • Imaging unit /C • Imaging unit /M • Imaging unit /Y • Toner cartridge /C • Toner cartridge /M • Toner cartridge /Y • Sub hopper unit • Printer control board (PRCB)
• Remedy: 1 Reinstall toner cartridge. 2 Reinstall imaging unit. 3 Replace imaging unit. 4 Replace PRCB. 5 Replace the sub hopper unit.

• Code: C2555
• Description: Abnormally low toner density detected yellow 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.
• Causes: • Imaging unit /C • Imaging unit /M • Imaging unit /Y • Toner cartridge /C • Toner cartridge /M • Toner cartridge /Y • Toner empty sensor/C (RS/C) • Toner empty sensor/M (RS/M) • Toner empty sensor/Y (RS/Y) • Toner supply motor/Y (M9) • Toner supply motor/M (M10) • Toner supply motor/C (M11) • Toner cartridge motor /YM (M13) • Toner cartridge motor /CK (M14) • Printer control board (PRCB)
• Remedy: 1 Perform image troubleshooting procedure if image density is low. 2 Reinstall imaging unit. 3 Reinstall toner cartridge. 4 Check the motor connector for proper connection and correct as necessary. 5 Check the connector of M9, M10, M11, M13, M14 for proper drive coupling and correct as necessary. 6 M9, M10, M11 operation check (At this time, IU must be non-installation.) M9: PRCB CN3-1 to 4 M10: PRCB CN3-5 to 8 M11: PRCB CN3-9 to 12 23 to 24-C. 7 M13, M14 operation check M13: PRCB CN4-1 to 4 M14: PRCB CN4-5 to 8 3-K. 8 Replace M9, M10, M11, M13, M14. 9 If the toner empty sensor and its surroundings inside the sub hopper are dirtied with toner, clean them. 10 Replace imaging unit. 11 PRCB ICP23 or ICP24 conduction check. 12 Replace PRCB.

• Code: C2556
• Description: Abnormally high toner density detected yellow TCR sensor
  TC ratio in the developing unit, which is determined by toner replenishing amount control mechanism, is a predetermined value or more for a given number of times consecutively.
• Causes: • Imaging unit /C • Imaging unit /M • Imaging unit /Y • Toner cartridge /C • Toner cartridge /M • Toner cartridge /Y • Sub hopper unit • Printer control board (PRCB)
• Remedy: 1 Reinstall toner cartridge. 2 Reinstall imaging unit. 3 Replace imaging unit. 4 Replace PRCB. 5 Replace the sub hopper unit.

• Code: C2557
• Description: Abnormally low toner density detected black 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
• Causes: • Developing unit /K • Toner cartridge /K • Toner empty sensor/K (PZS/K) • Toner supply motor/K (M12) • Toner cartridge motor /CK (M14) • Printer control board (PRCB)
• Remedy: 1 Perform image troubleshooting procedure if image density is low. 2 Check the connector between M12-relay CN258- PRCB CN3 for proper connection, and correct as necessary. 3 Check the connector between M14-relay CN321-relay CN428-PRCB CN4 for proper connection, and correct as necessary. 4 Check the connector of M12 and M14 for proper drive coupling and correct as necessary. 5 M12 operation check (At this time, IU must be non-installation.) PRCB CN3-13 to 16 24-C. 6 M14 operation check PRCB CN4-5 to 8 3-K. 7 Replace M12 and M14. 8 Reinstall developing unit /K. 9 Reinstall toner cartridge. 10 If the toner empty sensor and its surroundings inside the sub hopper are dirtied with toner, clean them. 11 Replace the developing unit /K. 12 PRCB ICP23 or ICP24 conduction check. 13 Replace PRCB.

• Code: C2558
• Description: Abnormally high toner density detected black TCR sensor
  TC ratio in the developing unit, which is determined by toner replenishing amount control mechanism, is a predetermined value or more for a given number of times consecutively.
• Causes: • Developing unit /K • Toner cartridge /K • Sub hopper unit • Printer control board (PRCB)
• Remedy: 1 Reinstall developing unit/K. 2 Reinstall toner cartridge. 3 Replace the developing unit/K. 4 Replace PRCB. 5 Replace the sub hopper unit.

• Code: C2559
• Description: Cyan TCR sensor adjustment failure
  TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Imaging unit /C • Imaging unit /M • Imaging unit /Y • Printer control board (PRCB)
• Remedy: 1 Reinstall imaging unit. 2 Replace the imaging unit. 3 PRCB ICP23 or ICP24 conduction check. 4 Replace PRCB.

• Code: C255A
• Description: Magenta TCR sensor adjustment failure
  TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Imaging unit /C • Imaging unit /M • Imaging unit /Y • Printer control board (PRCB)
• Remedy: 1 Reinstall imaging unit. 2 Replace the imaging unit. 3 PRCB ICP23 or ICP24 conduction check. 4 Replace PRCB.

• Code: C255B
• Description: Yellow TCR sensor adjustment failure
  TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Imaging unit /C • Imaging unit /M • Imaging unit /Y • Printer control board (PRCB)
• Remedy: 1 Reinstall imaging unit. 2 Replace the imaging unit. 3 PRCB ICP23 or ICP24 conduction check. 4 Replace PRCB.