• Code: C7403
• Description: Developing unit M type mismatch problem
  Absence of the developing unit M is detected.
• Causes: Developing unit connector inserted incorrectly. Different type of the developing unit is installed.
• Remedy: Developing unit connector inserted incorrectly. Reinsert the developing unit connector if necessary.
  Different type of the developing unit is installed. Install the correct developing unit.

• Code: C7404
• Description: Developing unit Y type mismatch problem
  Absence of the developing unit Y is detected.
• Causes: Developing unit connector inserted incorrectly. Different type of the developing unit is installed.
• Remedy: Developing unit connector inserted incorrectly. Reinsert the developing unit connector if necessary.
  Different type of the developing unit is installed. Install the correct developing unit.

• Code: C7411
• Description: Drum unit K type mismatch problem
  Absence of the drum unit K is detected.
• Causes: Drum unit connector inserted incorrectly. Different type of the drum unit is installed.
• Remedy: Drum unit connector inserted incorrectly. Reinsert the drum unit connector if necessary.
  Different type of the drum unit is installed. Install the correct drum unit.

• Code: C7412
• Description: Drum unit C type mismatch problem
  Absence of the drum unit C is detected.
• Causes: Drum unit connector inserted incorrectly. Different type of the drum unit is installed.
• Remedy: Drum unit connector inserted incorrectly. Reinsert the drum unit connector if necessary.
  Different type of the drum unit is installed. Install the correct drum unit.

• Code: C7413
• Description: Drum unit M type mismatch problem
  Absence of the drum unit M is detected.
• Causes: Drum unit connector inserted incorrectly. Different type of the drum unit is installed.
• Remedy: Drum unit connector inserted incorrectly. Reinsert the drum unit connector if necessary.
  Different type of the drum unit is installed. Install the correct drum unit.

• Code: C7414
• Description: Drum unit Y type mismatch problem
  Absence of the drum unit Y is detected.
• Causes: Drum unit connector inserted incorrectly. Different type of the drum unit is installed.
• Remedy: Drum unit connector inserted incorrectly. Reinsert the drum unit connector if necessary.
  Different type of the drum unit is installed. Install the correct drum unit.

• Code: C7420
• Description: Transfer belt unit type mismatch problem
  Absence of the transfer belt unit is detected.
• Causes: Transfer belt unit connector inserted incorrectly. Different type of the transfer belt unit is installed.
• Remedy: Transfer belt unit connector inserted incorrectly. Reinsert the transfer belt unit connector if necessary.
  Different type of the transfer belt unit is installed. Install the correct transfer belt unit.

• Code: C7601
• Description: ID sensor 1 error
  An abnormal value is detected in the input data to ID sensor 1.
• Causes: Poor contact in the connector terminals. Defective engine PWB.
• Remedy: Poor contact in the connector terminals. Check the connection of connector YC8 on the engine PWB and the continuity across the connector terminals. Repair or replace if necessary.
  Defective engine PWB. Replace the engine PWB and check for correct operation.