• Code: 6400
• Description: Zero-cross signal error
  While fuser heater ON/OFF control is performed, the zero-cross signal is not input within 3 s.
• Causes: Defective connector cable or poor contact in the connector.
  Defective fuser heater PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Fuser heater PWB (YC29) and feed PWB 1 (YC27)
  Defective fuser heater PWB. Replace the fuser heater PWB and check for correct operation.

• Code: 6900
• Description: Fuser front fan motor error
  When the fuser front fan motor is driven, alarm signal is detected for 5 s continuously.
• Causes: Defective connector cable or poor contact in the connector.
  Defective fuser front fan motor.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Fuser front fan motor and front PWB (YC11) Front PWB (YC2) and engine PWB (YC8)
  Defective fuser front fan motor. Replace the fuser front fan motor.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 6910
• Description: Fuser rear fan motor error
  When the fuser rear fan motor is driven, alarm signal is detected for 5 s continuously.
• Causes: Defective connector cable or poor contact in the connector.
  Defective fuser rear fan motor.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Fuser rear fan motor and engine PWB (YC26)
  Defective fuser rear fan motor. Replace the fuser rear fan motor.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7001
• Description: Toner motor error
  A state in which the lock signal is detected for 20 times has been detected 3 times during the toner motor is activated.
• Causes: Defective connector cable or poor contact in the connector.
  Defective toner motor.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Toner motor and engine PWB (YC27)
  Defective toner motor. Replace the toner motor.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7101
• Description: Toner sensor error
  Sensor output value of 60 or less or 944 or more continued for 3 s.
• Causes: Defective connector cable or poor contact in the connector.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Toner sensor and front PWB (YC7) Front PWB (YC2) and engine PWB (YC8)
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7200
• Description: Broken outer temperature sensor wire
  The sensor input sampling is greater than 230.
• Causes: Defective connector cable or poor contact in the connector.
  Defective outer temperature sensor.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Outer temperature sensor and front PWB (YC8) Front PWB (YC2) and engine PWB (YC8)
  Defective outer temperature sensor. Replace outer temperature sensor.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7210
• Description: Short-circuited outer temperature sensor
  The sensor input sampling is less than 69.
• Causes: Defective connector cable or poor contact in the connector.
  Defective outer temperature sensor.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Outer temperature sensor 2 and front PWB (YC8) Front PWB (YC2) and engine PWB (YC8)
  Defective outer temperature sensor. Replace outer temperature sensor.
  Defective engine PWB. Replace the engine PWB and check for correct operation.

• Code: 7221
• Description: Broken LSU thermistor wire
  The sensor input sampling is greater than 230.
• Causes: Defective connector cable or poor contact in the connector.
  Defective LSU thermistor.
  Defective engine PWB.
• Remedy: Defective connector cable or poor contact in the connector. Reinsert the connector. Also check for continuity within the connector cable. If none, replace the cable. Laser scanner unit and LSU relay PWB (YC3) LSU relay PWB (YC2) and engine PWB (YC11)
  Defective LSU thermistor. Replace the laser scanner unit.
  Defective engine PWB. Replace the engine PWB and check for correct operation.