• Code: 6020
• Description: Abnormally high fuser thermistor temperature Fuser thermistor detects abnormally temperature.
• Remedy: Shorted fuser thermistor. Replace the fuser unit.
  Defective control PWB. Replace the control PWB.

• Code: 6030
• Description: Broken fuser thermistor wire Input from fuser thermistor is 0 (A/D value).
• Remedy: Poor contact in the fuser thermistor connector terminals. Reinsert the connector.
  Broken fuser thermistor wire. Replace the fuser unit.
  Fuser thermistor installed incorrectly. Replace the fuser unit.
  Fuser thermal cutout triggered. Replace the fuser unit.
  Fuser heater installed incorrectly. Replace the fuser unit.
  Broken Fuser heater wire. Replace the fuser unit.

• Code: 6400
• Description: Zero cross signal error The zero cross signal does not reach the control PWB for specified time.
• Remedy: Defective harness between high voltage PWB (YC202) and control PWB (YC23), or improper connector insertion. Reinsert the connector. Also check for continuity within the connector harness. If none, remedy or replace the harness.
  Defective connection between power source PWB (YC103) and high voltage PWB (YC201). Reinsert the connector.
  Defective power source PWB. Replace the power source PWB.
  Defective control PWB. Replace the control PWB.

• Code: 7990
• Description: Waste toner full The waste toner sensor has detected that the waste toner reservoir (drum unit) is full.
• Remedy: Waste toner reservoir (drum unit) is full. Turn the power switch off/on to restart the machine. If the error is not resolved, replace the drum unit.
  Defective waste toner sensor. Replace the waste toner sensor.
  Defective control PWB. Replace the control PWB.

• Code: F000
• Description: Control PWB - Operation panel PWB communication error
• Remedy: Defective harness between operation panel PWB (YC1) and control PWB (YC7), or improper connector insertion. Reinsert the connector. Also check for continuity within the connector harness. If none, remedy or replace the harness.
  Defective operation panel PWB. Replace the operation panel PWB.
  Defective control PWB. Replace the control PWB.

• Code: F020
• Description: Control PWB RAM checksum error
• Remedy: Defective main memory (RAM) on the control PWB. Turn the power switch off/on to restart the machine. If the error is not resolved, replace control PWB.
  Defective expanded memory (DIMM). Replace the expanded memory (DIMM).

• Code: F040
• Description: Control PWB engine communication error A communication error is detected.
• Remedy: Defective control PWB. Turn the power switch off/on to restart the machine. If the error is not resolved, replace control PWB.

• Code: F041
• Description: Control PWB - scanner PWB communication error A communication error is detected.
• Remedy: Defective control PWB or scanner PWB. Turn the power switch off/on to restart the machine. If the error is not resolved, replace control PWB or scanner PWB.