Hello Snowydoo21,
Actually, the answer to your question is in the Xerox Online Support Assistant here on Xerox.com. Here is the link to the WorkCentre C2424 Knowledge Base.
http://www.support.xerox.com/support/workcentre-c2424/support/enus.html
Just click on Fault Code Search which appears directly under the Search field and enter the fault code 39,003.40 exactly as I just did here. The Knowledge Base article that should come up will be for a Scanner Optical Test failure and there is one solution to try that contains step by step instructions as well as color pictures to resolve the problem.
Hopefully this helps. If not, at the top of the Knowledge Base window you will find the 800 number for contacting the Xerox Customer Technical Support Center at 800.821.2797.
