Error code 840-002 in clc 5100 color laser printer when i take copies from paper deck R1

Disable potential control by going into service mode Copier > Option > Tempo > F-POT-SW. Now copies can be run.
1) A solid black copy means laser is defective.
2) A white copy means you should check the Primary corona and HVT.
3) A good copy means you should check the Potential sensor PCB.

try Sevice mode Function_ Fuser _ E000 RLS.

Go to Service mode (Function _ Install _ 2nd Screen i.e. 2/4 make img reg 0 Restart machine Again Go to intall press init c aftrer complition press sinitc aftre getting it ready again make img reg to "1"

Error :
Intermittent E020 / E061 codes.

Workaround :
It's possible that there is a poor drum ground from the static eliminator brush. You may need to replace the static brush with the drum grounding leaf spring from a CLC 350 (part numberFA5-9308-000). Follow the procedure in technical publication CTP.NO 700/800-69.
Error :
E020 sub code 0440 and light density on all colors

Workaround :
Check the developer assembly movement, i.e. up & down and that the magnetic roller is turning. Check the EPC readings, laser output, fold back mirror, and the connectors for the developer and the developer bias contacts. If all the above checks are good, then the problem can be with the AC voltage output of the developer bias HVT. The DC-voltage for the developer bias is split between two colors ( magenta & yellow ) or ( cyan & black ). The AC voltage is supplied for all four colors and it's loss will be seen in all the colors whereas the loss of the DC voltage would affect only two colors. To fix the problem replace the developer bias HVT part # FG5-3068-060.

Hello sir; The error code you display it's means " external heat roller sensor damage , replace it.

On my CLC 1150 copier machine, I have an error code E071 – 0002.

Sir plz send soluation this error

there maybe a piece of paper or some dust in one of the transfer drum drawer connectors, also in the transfer drum home position sensors ther may be toner or paper dust.

I did not see that error code on Canons web site. It may have something to do with the laser or a pinched wire with one of the lasers. Also, which color is giving you a E020 code? It may have something to do with the other.

This error has to do with Toner concentration of the Black ( 04 ) part of the sub code. The "00" has to do with the reference level or signal value for black. Look to see if the Black toner sensor is soiled. You have to swing out the toner hopper assembly to access the sensor. You will see two thin gray cables coming down from under the control panel. Since you have access to both assemblies - toner and paper jam detect - carefully remove both and clean with canned air. Be careful since you are so near to the $800 drum. Replace both and test. If you still have problems and the drum is old, several years, and has over 40,000 copies on it, you may have to have the drum changed and I recommend a tech do it. Good Luck.