• 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 • Toner cartridge • 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, developing/drum unit must be noninstallation.) PRCB CN3-1 to 4 23-C 6 M14 operation check PRCB CN4-1 to 4 3-K 7 Replace M12 and M14 8 Reinstall developing unit 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 12 PRCB ICP23 or ICP24 conduction check 13 Replace PRCB.

• Code: C2558
• Description: Abnormally high toner density detected black TCR sensor The TC ratio of the toner determined by the toner replenishment control is detected to be the predetermined value or over for consecutive times.
• Causes: • Developing unit • Toner cartridge • Sub hopper unit • Printer control board (PRCB)
• Remedy: 1 Reinstall developing unit 2 Reinstall toner cartridge 3 Replace the developing unit 4 Replace PRCB 5 Replace the sub hopper unit

• Code: C255C
• Description: Black TCR sensor adjustment failure TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Developing unit • Printer control board (PRCB)
• Remedy: 1 Reinstall the developing unit 2 Replace the developing unit 3 PRCB ICP23 or ICP24 conduction check 4 Replace PRCB

• Code: C2564
• Description: Black TCR sensor failure Alarm signals for a TCR sensor is detected more than the predetermined number of times. This detection is used for detecting disconnection of TCR sensor connector.
• Causes: • Developing unit • PH relay board (PHRYB) • Printer control board (PRCB)
• Remedy: 1 Reinstall the developing unit 2 Check the harness from developing unit to PHRYB CN2 for proper connection and correct as necessary. • CN2: Developing unit 3 Replace the developing unit 4 PHRYB ICP2 or ICP5 conduction check 5 Replace PHRYB 6 Replace PRCB

• Code: C2650
• Description: Main backup media access error • The re-written data, which has been read out, checked and founded as error, is read out again and found as error. • The error was found when reading out the counter value. • MFP detects that the SSD board is not mounted.
• Causes: • SSD board (SSDB) • MFP board (MFPB) • Printer control board (PRCB)
• Remedy: 1 Check the connector from SSDB to MFPB for proper connection and correct as necessary. 2 Check the harness from MFPB to PRCB for proper connection and correct as necessary. 3 Replace MFPB 4 Replace PRCB 1. When the finisher or job separator has been installed, remove it once. 2. Check that the trouble code “C4802” appears and then display service mode. 3. Call the Enhanced Security to the screen. 4. Touch [Engine Data Backup]. 5. Touch [Engine Data Reflect mode], and press the Start key. 6. Select [Yes], and press the Start key again. 7. Check that the result “OK” appears. 8. Turn OFF the main power switch and turn it ON again more than 10 seconds after. 9. Update the PRCB firmware. 10. Make the specified readjustments. 5 If the above actions do not solve the problem, contact KM.

• Code: C2A14
• Description: Drum unit new release failure The status with the new unit is not cleared after the new drum unit is set.
• Causes: • Drum unit • Printer control board (PRCB)
• Remedy: 1 Clean the connection between the drum unit and the developing unit if dirty. 2 Reinstall the drum unit 3 Check the harness for proper connection and correct as necessary. 4 Replace the drum unit 5 Replace PRCB

• Code: C2A24
• Description: Toner cartridge new release failure The status with the new cartridge is not cleared after the new toner cartridge is set.
• Causes: • Toner cartridge • Printer control board (PRCB)
• Remedy: 1 Clean the connection between the toner cartridge and the machine if dirty. 2 Reinstall the toner cartridge 3 Check the harness for proper connection and correct as necessary. 4 Replace the toner cartridge 5 Replace PRCB

• Code: C3101
• Description: Fusing pressure roller separation failure • The fusing pressure home sensor (PS55) is not turned OFF (retracted state) even after the set period of time after the fusing pressure roller retraction operation is started. • The fusing pressure home sensor (PS55) is not OFF (retracted state) when the fusing pressure roller retraction operation is completed. • The fusing pressure home sensor (PS55) is not turned ON (pressed state) after the set period of time after the fusing pressure roller pressure operation is started. • The fusing pressure home sensor (PS55) is not ON (pressed state) when the fusing pressure roller pressure operation is completed.
• Causes: • Fusing pressure home sensor (PS55) • Fusing pressure motor (M29) • Printer control board (PRCB) • Fusing unit
• Remedy: 1 Check the connector between M29-PRCB CN29 for proper connection and correct as necessary. 2 Check the connector of M29 for proper drive coupling and correct as necessary. 3 Check the connector between PS55-PRCB CN17 for proper connection and correct as necessary. 4 PS55 I/O check, sensor check 5 M29 operation check PRCB CN29-1 to 4 8-K 6 Replace M29 7 Replace the fusing unit 8 PRCB ICP15 or ICP25 conduction check 9 Replace PRCB