At this point, I would recommend on onsite service call: 1-800-821-2797
The article referred to contains some information which may well prove useful in the future however the only point that I can see that might apply to my current problem refers to toner leakage and that has already been checked by 2 Xerox engineers who have looked at the printer and determined that is not the problem.
I found this article with some tips on reducing toner usage. If you need more assistance, please call Support: 1-800-821-2797
I have a problem with my 1 year old Xerox C315 printer in that it is using an excessive amount of yellow toner that 2 visits by Xerox engineers have failed to resolve. I'm a home user and the printer stats tells me that I have only printed 1259 pages of which 526 were mono and 733 colour. The yellow starter toner ran out in a couple of months and it was initially thought that the problem was with this cartridge and Xerox sent me a replacement standard cartridge. Using toner cartridge capacities and the reported percentage remaining figures then I calculate that I have used 860 pages of magenta, 960 pages of cyan and 1380 pages of black which are at least approximately in line with the actual pages printed. The yellow figure however is 2560! Early on I did print maybe 200 leaflets that included colour photographsbut but for the most part I'm printing meeting agendas and minutes plus my credit card statements none of which have much if any colour in them. Certainly no yellow backgrounds! Any ides as to what the problem might be.