E751 can be displayed when a connection error of the drum unit or toner cartridge occurs. The following are the detail of each sub code. You may find it helpful to refer to them when servicing. The suffix "x" of each sub code shows color of the affected drum unit or toner cartridge. (1=Y, 2=M, 3=C, and 4=k)
- 000x: Drum unit connection error (on printer side)
- 100x: Toner cartridge connection error (on printer side)
- 010x: Drum unit memory writing error
- 110x: Toner cartridge memory writing error
- 020x: Drum unit memory data error
- 120x: Toner cartridge memory data error
- 030x: Drum unit memory writing error (The number of reties exceeds the specified value.)
- 130x: Toner cartridge memory writing error (The number of reties exceeds the specified value.)
Though it can be memory related, it looks like a E751-1003 is Toner cartridge connection error (on printer side) Check the cyan drum or the cyan toner cartridge for now. Keep us posted when you try some of the details above.