My copier canon IR400 displays the error code E803,i need the meaning of the code.

Hello yaseen,
I just answered this question recently for someone. The fluorescent lamp that illuminates the image of the document you wish to copy/scan has become weak. When you first power up the copier it goes through a series of checks and adjustments to make sure you have the best quality copy. One of those checks is to turn the scan lamp on, that value is measured, and then the lamp voltage is adjusted up and down till it reaches a "target". If the target cannot be met(and in your case the light intensity could not be raised enough) then you will get this error code. I will try to help. To verify the lamp is even coming on, turn the true main power switch off. Then power up the copier and observe the scan lamp. At some point during the initial start up the lamp should come on for its measurement. In order to see this the document feeder must be in the up position. If the lamp does not come on then the most likely fix is a new lamp (we hope its not the circuitry that drives the lamp). So, if it does indeed come on then here's what we can try. ATTENTION!!!! the following suggestions REQUIRE that the copier is TOTALLY UNPLUGGED !!!. This is a DANGEROUS AREA to be near if the copier is plugged in ! OK? Ok, remove the large copy board glass. On your device I believe there are 2 screws to the right of it that allow you to remove a cover which then allows you to remove the glass. Clean it thoroughly on both sides keeping in mind the orientation of the glass. set it aside. Now by hand , slide/pull the scan lamp assembly to the right, the direction it moves naturally as it scans a document..There will be some slight resistance. Locate the lamp and with a moist(not wet) soft cloth clean the lamp. Follow that with a dry soft cloth. Make it perfectly clean especially at the ends. Notice the shiny reflectors around the lamp.Clean those as well. While you are there, clean the 3 mirrors that bounce the light/ image. Just look for 1 mirror below the lamp, and 2 mirrors that are located to the left of the lamp, the distance of the 2 mirrorrs from the lamp will vary depending on how far you move the scanner/lamp assembly.Now here's the part where I have to help you visualize something that I can't point to and that you never new existed so bare with me.
There is a plate you need to clean that is to your left. If you push the scanner all the way to the left until it stops you will have found the scanner's "home position". When the copier first comes on and does it's checks it turns the lamp on (while at its home position) and reflects light against a plate called the "standard white plate". It is used as a referrence for what "perfect white" should be. It needs to be cleaned. So move the scanner to the right again so you can get to the area where the lamp would have looked at if it were "home" and doing it's self check. You can't see it, but its an area that would be above the lamp if it were home.So its underneath what you see. Clean it as well. Just clean everthing in that "underneath area". Same method, perhaps a bit of glass cleaner HERE only. Use as many soft cloths as needed. Ok, finally, wipe the actual lamp itself off one last time with a moist cloth and a little alcohol. The lamp needs to be free of the oils of your fingers. Make sure everthing is clean and dry. We want everything to be bright and shiny. Now re-install the copy board glass and power the copier up. Now there is no doubt that the lamp is weak, but it may be able to now boost it's ouput enough to hit the "target" it needs to. I hope this helps. Take care, and let "FIXYA" know if I did indeed help. :-) SPINAL