• Code: L4-02
• Description: Drum motor trouble
• Causes: The motor lock signal is detected during rotation of the drum motor. Drum motor trouble. Harness and connector connection trouble. PCU PWB trouble. Developing unit trouble. Drum unit trouble.
• Remedy: Use SIM25-1 to check the operation of the drum motor. Replace the drum motor. Check connection of the connectors and the harness. Replace the PCU PWB. Replace the developing unit. Replace the drum unit.

• Code: L4-03
• Description: Fusing motor trouble
• Causes: The motor lock signal is detected during rotation of the fusing motor. Fusing motor trouble. Connection trouble of the connector and the harness. PCU PWB trouble.
• Remedy: Use SIM6-1 to check the operation of the fusing motor. Replace the Fusing motor. Check connection of the connectors and the harness. Replace the PCU PWB.

• Code: L4-04
• Description: Developing motor trouble
• Causes: The motor lock signal is detected during rotation of the developing motor. Developing motor trouble. Harness and connector connection trouble. PCU PWB trouble Developing unit trouble.
• Remedy: Use SIM25-1 to check the operation of the developing motor. Replace the developing motor. Check connection of the connectors and the harness. Replace the PCU PWB. Replace the developing unit.

• Code: L4-06
• Description: Transfer separation motor trouble
• Causes: Transfer separation motor trouble. Harness and connector connection trouble. PCU PWB trouble.
• Remedy: Use SIM6-3 to check the operation of the transfer separation motor. Replace the transfer separation motor. Check connection of the connectors and the harness. Replace the PCU PWB.

• Code: L4-08
• Description: Waste toner transport trouble
• Causes: Drum motor trouble. Waste toner transport pipe clogging. Harness and connector connection trouble. Waste toner lock sensor trouble.
• Remedy: Use SIM6-1 to check the operation of the drum motor. Replace the drum motor. Check connection of the connectors and the harness. Check the waste toner transport pipe for clogging. Replace the waste toner lock sensor. Replace the PCU PWB.

• Code: L4-30
• Description: MFP fan motor trouble
• Causes: Fan motor trouble. MFP PWB trouble.Harness and connector connection trouble. PCU PWB trouble
• Remedy: Use SIM6-2 to check the operation of the fan motor. Replace the fan motor. Replace the MFP PWB. Check connection of the connector and the harness. Replace the PCU PWB.

• Code: L4-31
• Description: Fusing section cooling fan (CFM-U1/3) trouble
• Causes: The fan operation signal is not detected within the specified time in the fusing section cooling fan operation. Fusing section cooling fan trouble. PCU PWB trouble. Connection trouble of the connector and the harness.
• Remedy: Check connection of the connectors and the harness. Use SIM6-2 to check the rotating operation of the fan. Replace the fusing section cooling fan. Replace the PCU PWB.

• Code: L4-32
• Description: Power supply cooling fan (CFM-DC1/DC2) trouble
• Causes: The fan operation signal is not detected within the specified time in the power cooling fan operation.
  Power cooling fan trouble. PCU PWB trouble. Connection trouble of the connector and the harness.
• Remedy: Use SIM6-2 to check the operation of the fan motor. Replace the power cooling fan. Replace the PCU PWB. Check/replace the connector or the harness.