C2555 (bizhub C360i/C300i/C250i)
Contents
| Trouble type | C2555: Abnormally low toner density detected yellow TCR sensor | 
| Rank | B | 
| Trouble detection condition | When sampling data is determined in TC ratio calculation control, TCR sensor output is higher than a predetermined value for a predetermined number of times in a row even though there is toner in the sub hopper. | 
| Trouble isolation | – | 
| Relevant electrical parts | • Developing unit/C,M,Y  • Toner cartridge/C,M,YPH unit • Toner empty sensor/Y (PS34) • Toner empty sensor/M (PS33) • Toner empty sensor/C (PS32) • Toner cartridge motor/YM (M10) • Toner cartridge motor/CK (M25) • Toner supply motor/Y (M9) • Toner supply motor/M (M8) • Toner supply motor/C (M7) • Expansion control board (EXCB) • CPU board (CPUB) • Base board (BASEB)  | 
Procedure
- Perform image troubleshooting procedure if image density is low.
 - Reinstall the developing unit.
 - Reinstall the toner cartridge.
 - Check the connector between the developing unit/C-relay CN251-relay CN248-EXCB CN6EX for proper connection and correct as necessary.
 - Check the connector between EXCB CN1EX-BASEB CN11E for proper connection and correct as necessary.
 - Check the connector between EXCB CN2EX-BASEB CN12E for proper connection and correct as necessary.
 - Check CPUB for proper installation and correct as necessary.
 - M10, M25 operation check
- Control signal: EXCB CN11EX-5 to 8 (M10), EXCB CN11EX-1 to 4 (M25)
 - Location of electrical component: 4-P
 
 - M7, M8, M9 operation check
- Control signal: EXCB CN11EX-17 to 20 (M7), EXCB CN11EX-13 to 16 (M8), EXCB CN11EX-9 to 12 (M9)
 - Location of electrical component: 5-P (M7), 4-P (M8, M9)
 
 - If the toner empty sensor and its surroundings inside the sub hopper are dirtied with toner, clean them.
 - Replace the corresponding developing unit.
 - Replace EXCB. (Part# AA2JH00500)
 - Replace CPUB. (Part# AA2JH02N06)
 - Replace BASEB. (Part# AA2JH02005)
 
Please search Knowledge Base articles and Bulletins as they may contain relevant information and updated Part information such as Part numbers.
L.3.8.7 (Link to the Field Service Manual)
