• Code: 6230
• Description: Broken fuser edge thermistor wire A/D value of the fuser thermistor 1 exceeds 252 bit (10 °C) continuously for 4 s during warming up.
• Causes: Fuser unit. Fuser thermistor 1. 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 thermistor 1 and Engine PWB (YC9) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. If the I/F connector pins of the fuser unit and the main unit are deformed owing to foreign matters, such as paper dusts, replace the connectors or the units including the connectors.
  Fuser thermistor 1 Replace the Fuser unit.
  Engine PWB Replace the engine PWB.

• Code: 6250
• Description: Abnormally low fuser edge thermistor temperature When the detection temperature of the fixing thermistor 1 is falling target temperature by 100 °C or more for 1 second after secondary stable temperature attainment.
• Causes: Fuser unit. Fuser thermostat. Fuser heater. 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 thermistor 1 and Engine PWB (YC9) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. If the I/F connector pins of the fuser unit and the main unit are deformed owing to foreign matters, such as paper dusts, replace the connectors or the units including the connectors.
  Fuser thermostat Fuser heater. Replace the Fuser unit.
  Engine PWB Replace the engine PWB.

• Code: 6400
• Description: Zero-cross signal error While fuser heater ON/OFF control is performed, the zerocross signal is not input within 3 s.
• Causes: Fuser unit
• Remedy: 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Power source PWB (YC7) and engine PWB (YC10) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the fuser heater PWB.

• Code: 6910
• Description: Engine software ready error The device won’t engage in ready state in 60 minutes after warming-up has began. (A previous timeout process has not been cancelled.)
• Causes: Engine PWB
• Remedy: 1. Turn the main power switch off and after 5 seconds, turn it on. 2. Reinstall the engine software. 3. Replace the engine PWB.

• Code: 7200
• Description: Broken outer temperature sensor 2 wire The sensor input sampling is greater than 818.
• Causes: APC PWB. Engine PWB
• Remedy: APC PWB 1. Confirm External Temp is displayed by U139 temperature and humidity. 2. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. APC PWB (YC1) and Engine PWB (YC4) 3. If the wiring is disconnected, shorted or grounded, replace the wiring. 4. Replace the BD PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7210
• Description: Short-circuited outer temperature sensor The temperature sensor input sampling is less than 353.
• Causes: APC PWB. Engine PWB
• Remedy: APC PWB 1. Confirm External Temp is displayed by U139 temperature and humidity. 2. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. APC PWB (YC1) and Engine PWB (YC4) 3. If the wiring is disconnected, shorted or grounded, replace the wiring. 4. Replace the BD PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7800
• Description: Broken outer temperature sensor wire The temperature sensor input sampling is more than 244.
• Causes: Thermistor PWB. Engine PWB
• Remedy: Thermistor PWB 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Thermistor PWB and Engine PWB (YC12). 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the thermistor PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.

• Code: 7810
• Description: Short-circuited external thermistor wire The temperature sensor input sampling is less than 11.
• Causes: Thermistor PWB, Engine PWB
• Remedy: Thermistor PWB 1. Confirm that the wiring connector is firmly connected and, if necessary, connect the connector all the way in. Thermistor PWB and Engine PWB (YC6) 2. If the wiring is disconnected, shorted or grounded, replace the wiring. 3. Replace the thermistor PWB.
  Engine PWB 1. Check the engine software and upgrade to the latest, if necessary. 2. Replace the engine PWB.