• Code: 2630
• Description: Option paper feeder PF-60 (Bottom) paper feed motor error
  Paper feed motor error in the bottom option paper feeder.
• Causes: Defective gate array U204 on the engine board (KP-864). Defective harness (S02400) between engine board and option unit interface connector. Defective paper feeder PF-60.

• Code: 4000
• Description: Laser scanner unit (Polygon motor) error
  POLRDY* does not go low within 20 seconds after POLON goes low (When starting) or within 16 seconds after REGPAP signal goes high (during printing).
• Causes: Defective gate array U204 on the engine board. Defective polygon motor. Improper connector insertion. Defective harness between laser scanner unit and engine board.

• Code: 4200
• Description: Laser scanner unit (Pin photo diode sensor) error
  Laser beam detection failed. The pin photo diode sensor [board] (KP-746) does not deliver a horizontal synchronous signal (PD).
• Causes: No laser beam due to the laser diode defect (PD). Soiled or defective pin photo diode sensor. Defective gate array U204 of engine board. Improper connector insertion. Defective harness between engine board and laser scanner unit.

• Code: 5300
• Description: Eraser lamp error
  The ERADEAD signal (delivered from the eraser lamp blown-out detection circuit on the engine board) goes low continuously more than 1 second, while eraser lamp is on.
• Causes: Blown-out eraser lamp [board KP-762]. Defective CPU U201 on the engine board. Improper connector insertion to the eraser lamp [board KP-762].

• Code: 6000
• Description: Fuser unit error
  HTEMP remains high for longer than 4 seconds since the heater lamp is on. The heater lamp continues to be turn on for longer than 60 seconds.
• Causes: Blown-out thermistor. Blown-out heater lamp. Defective CPU U201 or comparator U205 on the engine board. Improper connector insertion. Defective power supply unit. Defective harness between fuser unit and power supply unit.

• Code: 6020
• Description: Abnormal high temperature error
  CPU U201 detected that the HTEMP* signal (Abnormal temperature of more than approximately 220 °C) is low for more than 3 seconds
• Causes: Defective CPU U201 or comparator U205 on the engine board. Defective engine board (KP-864). Defective thermistor. Defective photo coupler on the power supply unit for the heater lamp.

• Code: 6400
• Description: Zero cross signal error
  The ZCROSS signal does not reach the engine board within 3 seconds after power on.
• Causes: Defective power supply unit. Defective CPU U201 on the engine board.

• Code: 7001
• Description: Toner motor error
  Toner motor is overloaded. TNMOC is detected by sampling every other 100 ms in 2 seconds since the main and toner motors are activated following the Replace toner Clean printer message after the Toner low TK-60 is detected.
• Causes: Overcurrent in the toner motor circuitry due to an excessive torque, caused by hardened toner. Defective gate array U204 on the engine board. Improper connector insertion. Defective harness between developer and high voltage unit. Defective harness between high voltage unit and engine board.