My 6128MFP started the exact same thing after 2 years of home use. I was about 50% through my second toner and wham, pale grey print. Replaced that toner again and the same thing. With the number of posts this sounds like maby a Xerox flaw.
I tried all of this for my 6128MFP that has the same problem. Gotta be a flaw in Xerox design they will not admit to.
Be very, very careful downloading service manuals. If site tells you you need to download DOC to PDF converter DO NOT DO IT!!! It will install adware and all kinds of other buge.
Your hint helped me access the service menu but I could not fix pale print problem.
Is anybody there at Xerox willing to help??? Did not think so. Not without $$$ My colors are bright and dense, only the black is pale.
I have the same problem with my 6128MFP and have gotten no help from Xerox except PAY US, PAY US. It sounds like Xerox should do a recall on all units that have whatever is faulty - and I am positive it is something faulty in design or programming.
It absolutely is a built in flaw. After months of frustration and no help from Xerox except "hire a tech" I was getting ready to pay a tech or trash my machine - then my machine did a long 'recalibration' all on it's own. A warning came up "Low Density Black - remove cartridge, shake and replace." Did another recal. and whadyah know, I have dark print again. Only 3900 total pages on my machine. The so called "Live Expert" never responded either. Well they don't collect money to fix a problem so they won't. THIS PROBLEM AND HOW TO FIX IT SHOULD BE PART OF THE TROUBLE SHOOTING IN THE MANUAL!!!
As much as I truly love my printer I doubt the integrity of Xerox to truly care for their little customers.
I am sorry for your frustration but there are many functions that are not serviceable by the customer due to safety and warranty policies. Your particular issue with light images requires a service technician if the device is not able to correct the issue through its internal calibration processes.
You can go to Menu > Admin Menu > Maintenance Mode where you will find several procedures you may run. Clear Developer, Toner Refresh, and Drum Refresh will all perform various types of maintenance calibrations. Additionally, after being turned on again after a set period of time, the printer will perform an auto-calibrate which will perform all three - possibly what you experienced after following the instructions identified by the device.
After trying the various solutions posted here I took a look at some who solved this problem with a 6130 and applied the fix to my 6125. Basically you should not run your cartridge after it is obvious that it is running low because the augers become empty. If you follow the link below it will ask you to run your toner motor to resolve that situation. I did and 3 pages later it was fine: http://www.fortwayneprinterrepair.com/wordpress/2014/03/17/xerox-phaser-6500-workcentre-6505-light-p...