• Code: F2-43
• Description: Toner density sensor trouble (YELLOW)
• Causes: Toner density sensor output abnormality (Sample level 25 or less, or 231 or above). Connection trouble of the connector and the harness. Developing unit trouble. PCU PWB trouble.
• Remedy: Replace the toner density sensor. Check connection of the connector and the harness. Replace the developing unit. Replace the PCU PWB.

• Code: F2-45
• Description: Color image density sensor trouble
• Causes: Color image density sensor sensitivity adjustment trouble. Color image density sensor trouble. Harness and connector connection trouble. Image density sensor dirt. Calibration plate dirt. Calibration plate solenoid trouble. PCU PWB trouble.
• Remedy: Replace the color image density sensor. Check connection of the connectors and the harness. Clean the image density sensor. Replace the calibration plate. Replace the calibration plate solenoid. Replace the PCU PWB. Use SIM44-2 to adjust the process control sensor sensitivity.

• Code: F2-49
• Description: LSU thermister trouble
• Causes: The LSU detection temperature is outside of -28C - 78C. LSU thermister trouble. Harness and connector connection trouble. PCU PWB trouble LSU control PWB trouble.
• Remedy: Replace the LSU thermistor. Check connection of the connectors and the harness. Replace the PCU PWB. Replace the LSU control PWB. Replace the LSU.

• Code: F2-50
• Description: K drum phase sensor trouble
• Causes: Drum phase sensor trouble. Harness and connector connection trouble. Drum drive section trouble. PCU PWB trouble
• Remedy: Use SIM30-1 to check the operation of "DHPD_K.". Replace the drum phase sensor. Check connection of the connectors and the harness. Repair the drum drive section. Replace the PCU PWB.

• Code: F2-51
• Description: CL drum phase sensor trouble (41-sheet machine) CL drum phase sensor trouble (CYAN) (50-sheet machine)
• Causes: Drum phase sensor trouble. Harness and connector connection trouble. Drum drive section trouble.
  PCU PWB trouble.
• Remedy: Use SIM30-1 to check the operation of "DHPD_CL". Replace the drum phase sensor. Check connection of the connectors and the harness. Repair the drum drive section. Replace the PCU PWB.

• Code: F2-52
• Description: CL drum phase sensor trouble (MAGENTA) (50-sheet machine)
• Causes: Drum phase sensor trouble. Harness and connector connection trouble. Drum drive section trouble. PCU PWB trouble.
• Remedy: Use SIM30-1 to check the operation of "DHPD_CL". Replace the drum phase sensor. Check connection of the connectors and the harness. Repair the drum drive section. Replace the PCU PWB.

• Code: F2-53
• Description: CL drum phase sensor trouble (YELLOW) (50-sheet machine)
• Causes: Drum phase sensor trouble. Harness and connector connection trouble. Drum drive section trouble. PCU PWB trouble.
• Remedy: Use SIM30-1 to check the operation of "DHPD_CL". Replace the drum phase sensor. Check connection of the connectors and the harness. Repair the drum drive section. Replace the PCU PWB.

• Code: F2-58
• Description: Process humidity sensor trouble
• Causes: Process humidity sensor trouble. Harness and connector connection trouble. PCU PWB trouble.
• Remedy: Replace the process humidity sensor. Check connection of the connectors and the harness. Replace the PCU PWB.