• Code: C2555
• Description: Abnormally low toner density detected yellow TCR sensor
• Causes: • Imaging unit/Y,M,C • Developing unit/K • Toner cartridge/Y,M,C,K • Toner empty sensor/Y (PS34) • Toner empty sensor/M (PS33) • Toner empty sensor/C (PS32) • Toner empty sensor/K (PS31) • Toner cartridge motor (M10) • Toner supply motor/Y,M (M9) • Toner supply motor/C,K (M7) • MFP board (MFPB)
• Remedy: 1. Perform image troubleshooting procedure if image density is low. 2. Reinstall the imaging unit. 3. Reinstall the developing unit/K. 4. Reinstall the toner cartridge. 5. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 6. M10 operation check • Control signal: MFPB CN26E-1 to 4 • Location of electrical component: 20-J 7. M7, M9 operation check • Control signal: MFPB CN28E-1 to 4 (M7), MFPB CN28E-5 to 8 (M9) • Location of electrical component: 19-J 8. If the toner empty sensor and its surroundings inside the sub hopper are dirtied with toner, clean them. 9. Replace the the corresponding imaging unit. 10. Replace the developing unit/K. 11. Replace MFPB. NOTICE • Link to the wiring diagram (N.1. bizhub C287/C227) • Link to the layout drawings for related parts by each trouble code (S.43. C2551) • Link to the layout drawings for related parts by each trouble code (S.45. C2553) • Link to the layout drawings for related parts by each trouble code (S.47. C2555) • Link to the layout drawings for related parts by each trouble code (S.49. C2557)

• Code: C2556
• Description: Abnormally high toner density detected yellow TCR sensor. The TC ratio of the toner determined by the toner replenishment control is detected to be the predetermined value or over for consecutive times.
• Causes: • Imaging unit/Y,M,C • Developing unit/K • MFP board (MFPB)
• Remedy: 1. Reinstall the imaging unit. 2. Reinstall the developing unit/K. 3. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 4. Replace the the corresponding imaging unit. 5. Replace the developing unit/K. 6. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.44. C2552, C2559, C2561, C2A11) • Link to the layout drawings for related parts by each trouble code (S.46. C2554, C255A, C2562, C2A12) • Link to the layout drawings for related parts by each trouble code (S.48. C2556, C255B, C2563, C2A13) • Link to the layout drawings for related parts by each trouble code (S.42. C2414, C2558, C255C, C2564)

• Code: C2557
• Description: Abnormally low toner density detected black TCR sensor
• Causes: • Imaging unit/Y,M,C • Developing unit/K • Toner cartridge/Y,M,C,K • Toner empty sensor/Y (PS34) • Toner empty sensor/M (PS33) • Toner empty sensor/C (PS32) • Toner empty sensor/K (PS31) • Toner cartridge motor (M10) • Toner supply motor/Y,M (M9) • Toner supply motor/C,K (M7) • MFP board (MFPB)
• Remedy: 1. Perform image troubleshooting procedure if image density is low. 2. Reinstall the imaging unit. 3. Reinstall the developing unit/K. 4. Reinstall the toner cartridge. 5. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 6. M10 operation check • Control signal: MFPB CN26E-1 to 4 • Location of electrical component: 20-J 7. M7, M9 operation check • Control signal: MFPB CN28E-1 to 4 (M7), MFPB CN28E-5 to 8 (M9) • Location of electrical component: 19-J 8. If the toner empty sensor and its surroundings inside the sub hopper are dirtied with toner, clean them. 9. Replace the the corresponding imaging unit. 10. Replace the developing unit/K. 11. Replace MFPB. NOTICE • Link to the wiring diagram (N.1. bizhub C287/C227) • Link to the layout drawings for related parts by each trouble code (S.43. C2551) • Link to the layout drawings for related parts by each trouble code (S.45. C2553) • Link to the layout drawings for related parts by each trouble code (S.47. C2555) • Link to the layout drawings for related parts by each trouble code (S.49. C2557)

• Code: C2558
• Description: Abnormally high toner density detected black TCR sensor. The TC ratio of the toner determined by the toner replenishment control is detected to be the predetermined value or over for consecutive times.
• Causes: • Imaging unit/Y,M,C • Developing unit/K • MFP board (MFPB)
• Remedy: 1. Reinstall the imaging unit. 2. Reinstall the developing unit/K. 3. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 4. Replace the the corresponding imaging unit. 5. Replace the developing unit/K. 6. Replace MFPB. NOTICE • Link to the layout drawings for related parts by each trouble code (S.44. C2552, C2559, C2561, C2A11) • Link to the layout drawings for related parts by each trouble code (S.46. C2554, C255A, C2562, C2A12) • Link to the layout drawings for related parts by each trouble code (S.48. C2556, C255B, C2563, C2A13) • Link to the layout drawings for related parts by each trouble code (S.42. C2414, C2558, C255C, C2564)

• Code: C2559
• Description: Cyan TCR sensor adjustment failure. TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Imaging unit/Y,M,C • Developing unit/K • MFP board (MFPB)
• Remedy: 1. Reinstall the imaging unit. 2. Reinstall the developing unit/K. 3. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 4. Replace the the corresponding imaging unit. 5. Replace the developing unit/K. 6. Replace MFPB. NOTICE • Link to the wiring diagram (N.1. bizhub C287/C227) • Link to the layout drawings for related parts by each trouble code (S.44. C2552, C2559, C2561, C2A11) • Link to the layout drawings for related parts by each trouble code (S.46. C2554, C255A, C2562, C2A12) • Link to the layout drawings for related parts by each trouble code (S.48. C2556, C255B, C2563, C2A13) • Link to the layout drawings for related parts by each trouble code (S.42. C2414, C2558, C255C, C2564)

• Code: C255A
• Description: Magenta TCR sensor adjustment failure. TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Imaging unit/Y,M,C • Developing unit/K • MFP board (MFPB)
• Remedy: 1. Reinstall the imaging unit. 2. Reinstall the developing unit/K. 3. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 4. Replace the the corresponding imaging unit. 5. Replace the developing unit/K. 6. Replace MFPB. NOTICE • Link to the wiring diagram (N.1. bizhub C287/C227) • Link to the layout drawings for related parts by each trouble code (S.44. C2552, C2559, C2561, C2A11) • Link to the layout drawings for related parts by each trouble code (S.46. C2554, C255A, C2562, C2A12) • Link to the layout drawings for related parts by each trouble code (S.48. C2556, C255B, C2563, C2A13) • Link to the layout drawings for related parts by each trouble code (S.42. C2414, C2558, C255C, C2564)

• Code: C255B
• Description: Yellow TCR sensor adjustment failure. TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Imaging unit/Y,M,C • Developing unit/K • MFP board (MFPB)
• Remedy: 1. Reinstall the imaging unit. 2. Reinstall the developing unit/K. 3. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 4. Replace the the corresponding imaging unit. 5. Replace the developing unit/K. 6. Replace MFPB. NOTICE • Link to the wiring diagram (N.1. bizhub C287/C227) • Link to the layout drawings for related parts by each trouble code (S.44. C2552, C2559, C2561, C2A11) • Link to the layout drawings for related parts by each trouble code (S.46. C2554, C255A, C2562, C2A12) • Link to the layout drawings for related parts by each trouble code (S.48. C2556, C255B, C2563, C2A13) • Link to the layout drawings for related parts by each trouble code (S.42. C2414, C2558, C255C, C2564)

• Code: C255C
• Description: Black TCR sensor adjustment failure. TCR sensor automatic adjustment does not function properly, failing to adjust to an appropriate value.
• Causes: • Imaging unit/Y,M,C • Developing unit/K • MFP board (MFPB)
• Remedy: 1. Reinstall the imaging unit. 2. Reinstall the developing unit/K. 3. Check the connector between the imaging unit or developing unit/K-relay CN161,CN162,CN163,CN164-relay CN15-MFPB CN18E for proper connection and correct as necessary. 4. Replace the the corresponding imaging unit. 5. Replace the developing unit/K. 6. Replace MFPB. NOTICE • Link to the wiring diagram (N.1. bizhub C287/C227) • Link to the layout drawings for related parts by each trouble code (S.44. C2552, C2559, C2561, C2A11) • Link to the layout drawings for related parts by each trouble code (S.46. C2554, C255A, C2562, C2A12) • Link to the layout drawings for related parts by each trouble code (S.48. C2556, C255B, C2563, C2A13) • Link to the layout drawings for related parts by each trouble code (S.42. C2414, C2558, C255C, C2564)