• Code: 7101
• Description: Toner sensor error (Black) For a certain period of time, the sensor output value is less than 0.1V, or more than 3.2V.
• Remedy: Toner container 1. Check that the toner container is properly installed, and if necessary, re-install. 2. Check that the toner supply inlet of the toner container can be opened by the lever operation. 3. Replace the toner container.
  Toner sensor 1. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. Toner sensor - Drum/Developer relay PWB Drum/Developer relay PWB - Engine PWB(YC6) 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Check if the gears and spirals in the developer unit rotate smoothly. 4. Replace the developer unit.
  Toner motor 1. Check that the toner motor is properly attached. 2. Check if the couplings and gears can rotate or if they are not unusually loaded, and if necessary, replace. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Toner motor - Engine PWB(YC14): 30 ppm model - Engine PWB(YC21): 35/40 ppm models 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the toner motor.
  Drum/developer relay PWB Replace the drum/developer relay PWB
  Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the engine PWB.

• Code: 7102
• Description: Toner sensor error (Cyan) For a certain period of time, the sensor output value is less than 0.1V, or more than 3.2V.
• Remedy: Toner container 1. Check that the toner container is properly installed, and if necessary, re-install. 2. Check that the toner supply inlet of the toner container can be opened by the lever operation. 3. Replace the toner container.
  Toner sensor 1. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. Toner sensor - Drum/Developer relay PWB Drum/Developer relay PWB - Engine PWB(YC6) 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Check if the gears and spirals in the developer unit rotate smoothly. 4. Replace the developer unit.
  Toner motor 1. Check that the toner motor is properly attached. 2. Check if the couplings and gears can rotate or if they are not unusually loaded, and if necessary, replace. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Toner motor - Engine PWB(YC14): 30 ppm model - Engine PWB(YC21): 35/40 ppm models 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the toner motor.
  Drum/developer relay PWB Replace the drum/developer relay PWB
  Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the engine PWB.

• Code: 7103
• Description: Toner sensor error (Magenta) For a certain period of time, the sensor output value is less than 0.1V, or more than 3.2V.
• Remedy: Toner container 1. Check that the toner container is properly installed, and if necessary, re-install. 2. Check that the toner supply inlet of the toner container can be opened by the lever operation. 3. Replace the toner container.
  Toner sensor 1. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. Toner sensor - Drum/Developer relay PWB Drum/Developer relay PWB - Engine PWB(YC6) 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Check if the gears and spirals in the developer unit rotate smoothly. 4. Replace the developer unit.
  Toner motor 1. Check that the toner motor is properly attached. 2. Check if the couplings and gears can rotate or if they are not unusually loaded, and if necessary, replace. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Toner motor - Engine PWB(YC14): 30 ppm model - Engine PWB(YC21): 35/40 ppm models 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the toner motor.
  Drum/developer relay PWB Replace the drum/developer relay PWB
  Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the engine PWB.

• Code: 7104
• Description: Toner sensor error (Yellow) For a certain period of time, the sensor output value is less than 0.1V, or more than 3.2V.
• Remedy: Toner container 1. Check that the toner container is properly installed, and if necessary, re-install. 2. Check that the toner supply inlet of the toner container can be opened by the lever operation. 3. Replace the toner container.
  Toner sensor 1. Confirm that the connector of the developer unit is firmly connected, and if necessary, push the unit all the way in. Toner sensor - Drum/Developer relay PWB Drum/Developer relay PWB - Engine PWB(YC6) 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Check if the gears and spirals in the developer unit rotate smoothly. 4. Replace the developer unit.
  Toner motor 1. Check that the toner motor is properly attached. 2. Check if the couplings and gears can rotate or if they are not unusually loaded, and if necessary, replace. 3. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Toner motor - Engine PWB(YC14): 30 ppm model - Engine PWB(YC21): 35/40 ppm models 4. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 5. Replace the toner motor.
  Drum/developer relay PWB Replace the drum/developer relay PWB
  Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the engine PWB.

• Code: 7200
• Description: Broken inner thermistor wire (Developer) The sensor input sampling value is greater than the reference value. (After detection, controlled at 25 °C/77.0 °F)
• Remedy: Developer unit BK 1. Confirm that the connector of the developer unit BK is firmly connected, and if necessary, push the unit all the way in. Toner sensor BK - Drum/Developer relay PWB(YC8) Drum/Developer relay PWB - Engine PWB(YC6) 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Replace the developer unit BK.
  Drum/developer relay PWB Replace the drum/developer relay PWB
  Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the engine PWB.

• Code: 7210
• Description: Short-circuited inner thermistor (Developer) The sensor input sampling value is less than the reference value. (After detection, controlled at 25 °C/77.0 °F)
• Remedy: Developer unit BK 1. Confirm that the connector of the developer unit BK is firmly connected, and if necessary, push the unit all the way in. Toner sensor BK - Drum/Developer relay PWB(YC8) Drum/Developer relay PWB - Engine PWB(YC6) 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Replace the developer unit BK.
  Drum/developer relay PWB Replace the drum/developer relay PWB
  Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the engine PWB.

• Code: 7221
• Description: Broken inner thermistor wire (LSU) The sensor input sampling value is greater than the reference value. (After detection, controlled at 25 °C/77.0 °F)
• Remedy: Laser scanner unit (LSU) 1. Confirm that the wiring connector of the LSU is firmly connected, and if necessary, connect the connector all the way in. LSU - Main PWB(YC2016): 30 ppm model LSU - Engine PWB(YC8): 35/40 ppm models 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Replace the LSU.
  Main PWB Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the main PWB. 3. Replace the engine PWB.

• Code: 7231
• Description: Short-circuited inner thermistor (LSU) The sensor input sampling value is less than the reference value. (After detection, controlled at 25 °C/77.0 °F)
• Remedy: Laser scanner unit (LSU) 1. Confirm that the wiring connector of the LSU is firmly connected, and if necessary, connect the connector all the way in. LSU - Main PWB(YC2016): 30 ppm model LSU - Engine PWB(YC8): 35/40 ppm models 2. If the wire is disconnected, short-circuited or has a ground fault, or the connector pin is deformed, replace the wire. 3. Replace the LSU.
  Main PWB Engine PWB 1. Check the engine firmware and upgrade to the latest version if necessary. 2. Replace the main PWB. 3. Replace the engine PWB.