• Code: C3731
• Description: Fusing abnormally high temperature detection (Hard protector). The hard protector signal error is detected for a given period of time consecutively.
• Causes: • Fusing unit • Heating roller thermistor/1 (TH1) • Heating roller temperature sensor (TEMS) • Heating roller thermistor/2 (TH2) • MFP board (MFPB)
• Remedy: 1. Check the fusing unit for correct installation (whether it is secured in position). 2. Check the open/close operation of the right door. 3. Check the connector between the fusing unit-relay CN4-MFPB CN16E for proper connection and correct as necessary. 4. Replace the fusing unit. 5. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.58. C3731)

• Code: C3825
• Description: Fusing abnormally low temperature detection (Main of the heating roller). The heating roller temperature sensor (TEMS) continues to detect a temperature lower than a predetermined one for a predetermined period of time.
• Causes: • Fusing unit • C3825: Heating roller temperature sensor (TEMS) • C3826: Heating roller thermistor/2 (TH2) • DC power supply (DCPU) • MFP board (MFPB
• Remedy: 1. Check the fusing unit for correct installation (whether it is secured in position). 2. Check the open/close operation of the right door. 3. Check the connector between the fusing unit-relay CN4-MFPB CN16E for proper connection and correct as necessary. 4. Replace the fusing unit. 5. Replace DCPU. 6. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.56. C3725, C3825, C3925) • Link to the layout drawings for related parts by each trouble code (S.57. C3726, C3826, C3926)

• Code: C3826
• Description: Fusing abnormally low temperature detection (Center of the heating roller). The heating roller thermistor/2 (TH2) continues to detect a temperature lower than a predetermined one for a predetermined period of time.
• Causes: • Fusing unit • C3825: Heating roller temperature sensor (TEMS) • C3826: Heating roller thermistor/2 (TH2) • DC power supply (DCPU) • MFP board (MFPB
• Remedy: 1. Check the fusing unit for correct installation (whether it is secured in position). 2. Check the open/close operation of the right door. 3. Check the connector between the fusing unit-relay CN4-MFPB CN16E for proper connection and correct as necessary. 4. Replace the fusing unit. 5. Replace DCPU. 6. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.56. C3725, C3825, C3925) • Link to the layout drawings for related parts by each trouble code (S.57. C3726, C3826, C3926)

• Code: C3922
• Description: Fusing sensor wire breaks detection (Edge of the heating roller). After a predetermined period of time after the warm-up stage is started, the heating roller thermistor/1 (TH1) voltage does not decrease by predetermined steps (temperature rise) within a predetermined period of time.
• Causes: • Fusing unit • C3922: Heating roller thermistor/1 (TH1) • C3925: Heating roller temperature sensor (TEMS) • C3926: Heating roller thermistor/2 (TH2) • DC power supply (DCPU) • MFP board (MFPB)
• Remedy: 1. Check the fusing unit for correct installation (whether it is secured in position). 2. Check the open/close operation of the right door. 3. Check the connector between the fusing unit-relay CN4-MFPB CN16E for proper connection and correct as necessary. 4. Replace the fusing unit. 5. Replace DCPU. 6. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.55. C3722, C3922) • Link to the layout drawings for related parts by each trouble code (S.56. C3725, C3825, C3925) • Link to the layout drawings for related parts by each trouble code (S.57. C3726, C3826, C3926)

• Code: C3925
• Description: Fusing sensor wire breaks detection (Main of the heating roller). After a predetermined period of time after the warm-up stage is started, the heating roller temperature sensor (TEMS) voltage does not increase by predetermined steps (temperature rise) within a predetermined period of time.
• Causes: • Fusing unit • C3922: Heating roller thermistor/1 (TH1) • C3925: Heating roller temperature sensor (TEMS) • C3926: Heating roller thermistor/2 (TH2) • DC power supply (DCPU) • MFP board (MFPB)
• Remedy: 1. Check the fusing unit for correct installation (whether it is secured in position). 2. Check the open/close operation of the right door. 3. Check the connector between the fusing unit-relay CN4-MFPB CN16E for proper connection and correct as necessary. 4. Replace the fusing unit. 5. Replace DCPU. 6. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.55. C3722, C3922) • Link to the layout drawings for related parts by each trouble code (S.56. C3725, C3825, C3925) • Link to the layout drawings for related parts by each trouble code (S.57. C3726, C3826, C3926)

• Code: C3926
• Description: Fusing sensor wire breaks detection (Center of the heating roller). After a predetermined period of time after the warm-up stage is started, the heating roller thermistor/2 (TH2) voltage does not decrease by predetermined steps (temperature rise) within a predetermined period of time.
• Causes: • Fusing unit • C3922: Heating roller thermistor/1 (TH1) • C3925: Heating roller temperature sensor (TEMS) • C3926: Heating roller thermistor/2 (TH2) • DC power supply (DCPU) • MFP board (MFPB)
• Remedy: 1. Check the fusing unit for correct installation (whether it is secured in position). 2. Check the open/close operation of the right door. 3. Check the connector between the fusing unit-relay CN4-MFPB CN16E for proper connection and correct as necessary. 4. Replace the fusing unit. 5. Replace DCPU. 6. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.55. C3722, C3922) • Link to the layout drawings for related parts by each trouble code (S.56. C3725, C3825, C3925) • Link to the layout drawings for related parts by each trouble code (S.57. C3726, C3826, C3926)

• Code: C392B
• Description: Fusing sensor wire breaks detection (Center of the heating roller). The difference between the temperature corrected by the heating roller thermistor/1 (TH1) and the temperature detected by the heating roller thermistor/2 (TH2) exceeds a predetermined value.
• Causes: • Fusing unit • Heating roller thermistor/1 (TH1) • Heating roller thermistor/2 (TH2) • MFP board (MFPB)
• Remedy: 1. Check the fusing unit for correct installation (whether it is secured in position). 2. Check the open/close operation of the right door. 3. Check the connector between the fusing unit-relay CN4-MFPB CN16E for proper connection and correct as necessary. 4. Replace the fusing unit. 5. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.59. C392B)

• Code: C40A1
• Description: Mechanical controller sub-CPU communication error. A CPU communication error is detected.
• Causes: MFP board (MFPB)
• Remedy: 1. Turn OFF the main power switch, disconnect and then connect the power cord. Wait for 10 sec. or more after connect the power cord, and turn ON the main power switch. 2. Rewrite the firmware. 3. MFPB F3E conduction check 4. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.60. C40A1 - C40A4, C5372, C5601 - C5606, CA051 - CA053, CC151, CC152, CC170 - CC186, CC191 - CC216, CD211 - CD242, CD401 - CD413, CD701 - CD703, CD705, CD706, CE001, CE003 - CE305, CEEE1, CEEE3)