• Code: 4201
• Description: BD steady-state error K
  The BD signal is not detected.
• Causes: PD PWB K (LSU). Engine PWB.
• Remedy: PD PWB K (LSU) 1. Confirm that the FCC wiring connector is not distorted and connect the FCC wiring all the way in. Laser scanner unit and LSU relay PWB (YC3) LSU relay PWB (YC2) and Engine PWB (YC11) 2. If the FCC wiring is disconnected, shorted or grounded, replace the FCC wiring. 3. Replace the laser scanner unit.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 5101
• Description: Main high-voltage error K
  Measure the inflowing current when Vpp is varied in 3 steps and verify if the difference of the currents of 0 and step 2 is less than 42 (51 if lower highvoltage board).
• Causes: Drum unit. Charger roller unit. High voltage PWB. Engine PWB
• Remedy: Drum unit 1. Confirm that the drum or the drum screw can rotate. 2. If it won’t rotate, replace the drum unit. 3. Check that the discharger lamp is properly connected.
  Charger roller unit 1. Check that the high-voltage contacts are not distorted or adhered with foreign objects. 2. Reinstall the chrager roller unit.Or, replace the charger roller unit.
  High voltage PWB 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. High voltage PWB (YC2) and Engine PWB (YC16) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the High voltage PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 6000
• Description: Broken fuser heater wire
  Fuser thermistor 1 does not reach 100° C/212 °F even after 30 s during warming up. The detected temperature of fuser thermistor 1 does not reach the specified temperature (ready indication temperature) for 420 s in warming up after reached to 100° C/212 °F.
• Causes: Fuser unit. Engine PWB. Power source PWB. Fuser heater.
• Remedy: Fuser unit 1. Check that no paper jam is present. 2. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and Engine PWB (YC26) 3. If the wiring is disconnected, shorted or grounded, replace the wiring. 4. Replace the Fuser unit and execute U167 counter clear. (Deteriorated sensitivity due to the toner adhered to the center thermistor.)
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.
  Power source PWB 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Power source PWB (YC3) and fuser heater PWB (YC3) Fuser heater PWB (YC2) and feed PWB 1 (YC27) Feed PWB 1 (YC1) and Engine PWB (YC6)
  Fuser heater 1. Replace the fuser unit.

• Code: 6020
• Description: Abnormally high fuser thermistor 1 temperature
  Fuser thermistor 1 detects a temperature higher than 240°C/464°F for 1 s.
• Causes: Fuser unit. Engine PWB.
• Remedy: Fuser unit 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and Engine PWB (YC26) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Fuser unit.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 6030
• Description: Broken fuser thermistor 1 wire
  Fuser thermistor 1 detects a lower then 30°C/86°F when the temperature at the fuser thermistor 2 is higher than 70°C/158°F for during werming up. Fuser thermistor 2 detects a lower then 50°C/122°F for 15s during werming up.
• Causes: Fuser unit. Engine PWB. Fuser thermistor 1. Fuser thermostat (triggered).
• Remedy: Fuser unit 1. Check that no paper jam is present. 2. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and Engine PWB (YC26) 3. If the wiring is disconnected, shorted or grounded, replace the wiring. 4. Replace the Fuser unit and execute U167 counter clear. (Deteriorated sensitivity due to the toner adhered to the center thermistor.)
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.
  Fuser thermistor 1 1. Replace the Fuser unit and execute U167 counter clear.
  Fuser thermostat (triggered) 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and fuser heater PWB (YC1) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Fuser unit and execute U167 counter clear.

• Code: 6040
• Description: Fuser heater error
  Input from fuser center thermistor 1 is abnormal value continuously for 1 s. CPU port PH1 to stay in H level for one second or more in all operating modes is judged that the connector is disconnected.
• Causes: Fuser unit. Engine PWB. Center thermistor 1. Fuser thermostat (triggered)
• Remedy: Fuser unit 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and Engine PWB (YC26) 2. If the wiring is disconnected, shorted or grounded, replace the wiring.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.
  Center thermistor 1 1. Replace the Fuser unit and execute U167 counter clear.
  Fuser thermostat (triggered) 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and fuser heater PWB (YC1) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Fuser unit and execute U167 counter clear.

• Code: 6050
• Description: Abnormally low fuser thermistor 1 temperature
  Fuser thermistor 1 detects a temperature lower than 100°C/212°F for 1 s after warming up, during ready or during print. The temperature of thermistor 1 is detected to be less than 70°C/158°F for more than one second during lowpower mode.
• Causes: Power source. Fuser unit. Engine PWB. Fuser thermistor 1. Fuser thermostat (triggered).
• Remedy: Power source 1. Check that the operating voltage falls within +/-10%. 2. Check no voltage drop is caused. The heater is deactivated at 70V or lower. 3. Relocate the AC outlet that supplies power.
  Fuser unit 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and Engine PWB (YC26) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Fuser unit and execute U167 counter clear.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 1. Replace the engine PWB.
  Fuser thermistor 1 1. Replace the fuser unit and execute U167 counter clear.
  Fuser thermostat (triggered) 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and fuser heater PWB (YC1) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Fuser unit and execute U167 counter clear.

• Code: 6200
• Description: Broken fuser edge heater wire
  Fuser thermistor 2 does not reach 100° C/212 °F even after 30 s during warming up. The detected temperature of fuser thermistor 2 does not reach the specified temperature (ready indication temperature) for 420 s in warming up after reached to 100° C/212 °F.
• Causes: Fuser unit. Engine PWB. Fuser center thermistor 1.
• Remedy: Fuser unit 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Fuser unit and Engine PWB (YC26) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the Fuser unit and execute U167 counter clear.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.
  Fuser center thermistor 1 1. Replace the Fuser unit and execute U167 counter clear.