• Code: 7002
• Description: Toner motor 2 overcurrent detection error (cyan toner)
  The engine controller PWB (A0004) detected the overcurrent of toner motor 2.
• Causes: Defective toner motor 2. Defective engine controller PWB (A0004). Lump of toner inside cyan toner container or defectiveness of toner replenishment drive system.
• Remedy: Defective toner motor 2. Replace the toner motor 2. See page 1-5- 50. Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Lump of toner inside cyan toner container or defectiveness of toner replenishment drive system. Replace the cyan toner container.

• Code: 7003
• Description: Toner motor 1 overcurrent detection error (magenta toner)
  The engine controller PWB (A0004) detected the overcurrent of toner motor 1.
• Causes: Defective toner motor 1. Defective engine controller PWB (A0004). Lump of toner inside magenta toner container or defectiveness of toner replenishment drive system.
• Remedy: Defective toner motor 1. Replace the toner motor 1. See page 1-5- 50. Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Lump of toner inside magenta toner container or defectiveness of toner replenishment drive system. Replace the magenta toner container.

• Code: 7004
• Description: Toner motor 3 overcurrent detection error (yellow toner)
  The engine controller PWB (A0004) detected the overcurrent of toner motor 3.
• Causes: Defective toner motor 3. Defective engine controller PWB (A0004). Lump of toner inside yellow toner container or defectiveness of toner replenishment drive system.
• Remedy: Defective toner motor 3. Replace the toner motor 3. See page 1-5- 50. Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Lump of toner inside yellow toner container or defectiveness of toner replenishment drive system. Replace the yellow toner container.

• Code: 7401
• Description: Black developer unit non- installing error
  The toner sensor 4 inside the black developer unit did not output the density detection signal, judged the engine controller PWB (A0004) the black developer unit is not installed.ЯP
• Causes: Defective harness of the toner sensor 4, defective connection of the connector between black developer unit and the printer main unit or poor contact of the connector terminals. Defective toner sensor 4. Defective engine controller PWB (A0004). Defective engine relay PWB (A0009).
• Remedy: Defective harness of the toner sensor 4, defective connection of the connector between black developer unit and the printer main unit or poor contact of the connector terminals. Check the damage of harness of the toner sensor 4, check the connection of the connector with the black developer unit and the printer main unit, if there is trouble, remedy or replace. Defective toner sensor 4. Replace the black developer unit. Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Defective engine relay PWB (A0009). Replace the engine relay PWB (A0009).

• Code: 7402
• Description: Cyan developer unit non- installing error
  The toner sensor 2 inside the cyan developer unit did not output the density detection signal, judged the engine controller PWB (A0004) the cyan developer unit is not installed.ed.ЯP
• Causes: Defective harness of the toner sensor 2, defective connection of the connector between cyan developer unit and the printer main unit or poor contact of the connector terminals. Defective toner sensor 2. Defective engine controller PWB (A0004). Defective engine relay PWB (A0009).
• Remedy: Defective harness of the toner sensor 2, defective connection of the connector between cyan developer unit and the printer main unit or poor contact of the connector terminals. Check the damage of harness of the toner sensor 2, check the connection of the connector with the cyan developer unit and the printer main unit, if there is trouble, remedy or replace. Defective toner sensor 2. Replace the cyan developer unit. Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Defective engine relay PWB (A0009). Replace the engine relay PWB (A0009).

• Code: 7403
• Description: Magenta developer unit non- installing error
  The toner sensor 1 inside the magenta developer unit did not output the density detection signal, judged the engine controller PWB (A0004) the magenta developer unit is not installed.
• Causes: Defective harness of the toner sensor 1, defective connection of the connector between magenta developer unit and the printer main unit or poor contact of the connector terminals. Defective toner sensor 1. Defective engine controller PWB (A0004). Defective engine relay PWB (A0009).
• Remedy: Defective harness of the toner sensor 1, defective connection of the connector between magenta developer unit and the printer main unit or poor contact of the connector terminals. Check the damage of harness of the toner sensor 1, check the connection of the connector with the magenta developer unit and the printer main unit, if there is trouble, remedy or replace. Defective toner sensor 1. Replace the magenta developer unit. Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Defective engine relay PWB (A0009). Replace the engine relay PWB (A0009).

• Code: 7404
• Description: Yellow developer unit non- installing error
  The toner sensor 3 inside the yellow developer unit did not output the density detection signal, judged the engine controller PWB (A0004) the yellow developer unit is not installed.
• Causes: Defective harness of the toner sensor 3, defective connection of the connector between yellow developer unit and the printer main unit or poor contact of the connector terminals. Defective toner sensor 3. Defective engine controller PWB (A0004). Defective engine relay PWB (A0009).
• Remedy: Defective harness of the toner sensor 3, defective connection of the connector between yellow developer unit and the printer main unit or poor contact of the connector terminals. Check the damage of harness of the toner sensor 3, check the connection of the connector with the yellow developer unit and the printer main unit, if there is trouble, remedy or replace. Defective toner sensor 3. Replace the yellow developer unit. Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Defective engine relay PWB (A0009). Replace the engine relay PWB (A0009).

• Code: 7411
• Description: Black drum unit non- installing error
  The EEPROM (U401) on the drum PWB 4 (KP-972) inside the black drum unit does not communicate normally. The incompatible drum unit is installed to the printer.
• Causes: Defective harness between drum PWB 4 (KP-972) and printer main unit or poor contact of the connector terminals. Installing the drum unit, which is incompatible with the printer specification. Defective drum PWB 4 (KP-972). Defective engine controller PWB (A0004). Defective LED print heads relay PWB (A0176). Defective harness (S03214) between engine controller PWB (A0004) and LED print heads relay PWB (A0176) or poor contact of the connector terminals.
• Remedy: Defective harness between drum PWB 4 (KP-972) and printer main unit or poor contact of the connector terminals. Check the connection of the black drum unit and the printer main unit, check the continuity of the harness (S03211), if there is trouble, remedy or replace. Installing the drum unit, which is incompatible with the printer specification. Install the compatible drum unit to the printer. Defective drum PWB 4 (KP-972). Replace the drum PWB 4 (KP-972). Defective engine controller PWB (A0004). Replace the engine controller PWB (A0004). Defective LED print heads relay PWB (A0176). Replace the LED print heads relay PWB (A0176). Defective harness (S03214) between engine controller PWB (A0004) and LED print heads relay PWB (A0176) or poor contact of the connector terminals. Check the continuity of the harness (S03214), check the connection YC3 connector of the engine controller PWB (A0004), if there is trouble, remedy or replace.