• Code: 78
• Description: Fuser unit failure
• Causes: 1 Harness connection failure between fuser unit connector and engine PCB. 2 Fuser unit failure.
• Remedy: 1 Harness connection failure between fuser unit connector and engine PCB Check the harness connection between the fuser unit connector and engine PCB, and reconnect it. 2 Fuser unit failure Replace the fuser unit.

• Code: 7C
• Description: Engine communication error
• Causes: 1 Harness connection failure between engine PCB and main PCB. 2 Engine PCB failure. 3 Main PCB failure.
• Remedy: 1 Harness connection failure between engine PCB and main PCB Check the harness connection between the engine PCB and main PCB, and reconnect it. 2 Engine PCB failure Replace the engine PCB ASSY. 3 Main PCB failure Replace the main PCB ASSY.

• Code: 7D
• Description: Dirt on drum unit
• Causes: 1 Dirt or dust on drum unit electrodes. 2 Charge HVPS PCB failure. 3 Engine PCB failure.
• Remedy: 1 Dirt or dust on drum unit electrodes Clean the electrodes on the drum unit. (Refer to Fig. 1-1 (P1-33).) 2 Charge HVPS PCB failure Replace the charge HVPS PCB ASSY. 3 Engine PCB failure Replace the engine PCB ASSY.

• Code: 82
• Description: Density patch measurement is not completed normally when implementing calibration from the control panel.
• Causes: 1 Density sensor shutter not operating smoothly or catching in some position. 2 Harness connection failure of density sensor holder ASSY. 3 Density sensor failure. 4 Transfer HVPS PCB failure. 5 Engine PCB failure.
• Remedy: 1 Density sensor shutter not operating smoothly or catching in some position Correct smooth operation of the density sensor shutter. 2 Harness connection failure of density sensor holder ASSY Check the harness connection of the density sensor holder ASSY and reconnect it. 3 Density sensor failure Replace the density sensor holder ASSY. 4 Transfer HVPS PCB failure Replace the transfer HVPS PCB ASSY. 5 Engine PCB failure Replace the engine PCB ASSY.

• Code: 84
• Description: Paper jam rear side of the machine
• Causes: 1 Harness connection failure of registration front sensor PCB ASSY, registration rear sensor PCB ASSY or paper eject sensor PCB ASSY. 2 Registration front actuator, registration rear actuator or paper eject actuator not operating smoothly or catching in some position. 3a Paper eject sensor PCB failure. 3b Registration front sensor PCB failure (MP/ T1/ LT). 3c Registration rear sensor PCB failure. 4 Engine PCB failure.
• Remedy: 1 Harness connection failure of registration front sensor PCB ASSY, registration rear sensor PCB ASSY or paper eject sensor PCB ASSY Check the harness connections of the registration front sensor PCB ASSY, registration rear sensor PCB ASSY and paper eject sensor PCB ASSY, and reconnect them. 2 Registration front actuator, registration rear actuator or paper eject actuator not operating smoothly or catching in some position. Correct smooth operation of the registration front actuator, registration rear actuator or paper eject actuator and ensure they are not catching in any positions. 3a Paper eject sensor PCB failure Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the fuser unit. (MP/ T1) Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the front door unit ASSY. 3b Registration front sensor PCB failure (MP/ T1/ LT) (LT) Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the LT paper feed frame unit. 3c Registration rear sensor PCB failure Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the front door unit ASSY. 4 Engine PCB failure Replace the engine PCB ASSY.

• Code: 85
• Description: Tray 1 (T1) is not installed into the machine.
• Causes: 1 T1 PE/edge sensor PCB failure. 2 Harness connection failure of T1 PE/edge sensor PCB ASSY. 3 Engine PCB failure.
• Remedy: 1 T1 PE/edge sensor PCB failure Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the T1 PE/edge sensor PCB ASSY. 2 Harness connection failure of T1 PE/edge sensor PCB ASSY Check the harness connection of the T1 PE/edge sensor PCB ASSY and reconnect it. 3 Engine PCB failure Replace the engine PCB ASSY.

• Code: 86
• Description: Tray 2 (T2) is not installed into the machine.
• Causes: 1 Cassette sensor failure.
• Remedy: Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the LT paper feed frame unit.

• Code: 88
• Description: Paper jam inside the machine
• Causes: 1 Harness connection failure of registration front sensor PCB ASSY, registration rear sensor PCB ASSY or paper eject sensor PCB ASSY. 2 Registration front actuator, registration rear actuator or paper eject actuator not operating smoothly or catching in some position. 3a Paper eject sensor PCB failure. 3b Registration front sensor PCB failure (MP/ T1/ LT). 3c Registration rear sensor PCB failure. 4 Engine PCB failure.
• Remedy: 1 Harness connection failure of registration front sensor PCB ASSY, registration rear sensor PCB ASSY or paper eject sensor PCB ASSY Check the harness connections of the registration front sensor PCB ASSY, registration rear sensor PCB ASSY and paper eject sensor PCB ASSY, and reconnect them. 2 Registration front actuator, registration rear actuator or paper eject actuator not operating smoothly or catching in some position. Correct smooth operation of the registration front actuator, registration rear actuator or paper eject actuator and ensure they are not catching in any positions. 3a Paper eject sensor PCB failure Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the fuser unit. (MP/ T1) Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the front door unit ASSY. 3b Registration front sensor PCB failure (MP/ T1/ LT) (LT) Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the LT paper feed frame unit. 3c Registration rear sensor PCB failure Check the sensor performance following the procedure described in “Maintenance mode 32”. If any problem occurs, replace the front door unit ASSY. 4 Engine PCB failure Replace the engine PCB ASSY.