• Code: C6220
• Description: Sub fixing heater high temperature error •Temperature detected by fixing unit thermistor 2 was 200°C or higher.
• Causes: Fixing unit thermistor 2 has shorted. The fixing heater control circuit on the power source PCB is broken.
• Remedy: Measure the resistance. If the resistance is 0Ω, replace fixing unit thermistor 2. Replace the power source PCB.

• Code: C6400
• Description: Zero-cross interruption error • The zero-cross signal was not input into CN3-1B on the engine main PCB for more than 5 s during fixing phase control.
• Causes: Connector terminals are loosely connected or are making poor contact. The power source PCB is defective. The engine main PCB is defective.
• Remedy: Check the connection of CN4-7 on the engine main PCB and CN9-1 on the power source PCB and continuity across the terminals. If there is abnormality, remedy or replace. Check if the zero-cross signal is output from CN9-1 on the power source PCB. If not, replace the PCB. Check if the zero-cross signal is input to CN4-7 on the engine main PCB. If not, replace the PCB.

• Code: C7101
• Description: Toner sensor error •Toner sensor input to CN2-9 on the engine main PCB was 4.6 V or higher. •Toner sensor input to CN2-9 on the engine main PCB was 0.8 V or lower.
• Causes:

  The toner sensor isdefective.The toner sensor connectorterminals areloosely connected orare making poorcontact.The developer isdefective.

• Remedy: Replace the toner sensor. Reinsert the connector. Also check for continuity across the terminal wire and if none, remedy or replace the wire. Replace the developer.

• Code: C7200
• Description: Broken developing thermistor connection • The temperature detected by the developing thermistor was 0°C or lower for 100 ms. • The temperature detected by the developing thermistor was 56°C or higher for 100 ms.
• Causes: The developing thermistor is not installed correctly. The developing thermistor connector terminals are loosely connected. The developing thermistor has a break. The developing thermistor has shorted.
• Remedy: Check and reinstall if necessary. Check the connection of CN2-1 on the engine main PCB and continuity across the terminals. If there is abnormality, remedy or replace. Measure the resistance. If the resistance is  ∞Ω, replace the developing thermistor. Measure the resistance. If the resistance is 0Ω, replace the developing thermistor.