Unless you have a Sprinter Compatible Diagnistic reader (like the DAD unit, the DRBIII at the Dodge Dealerships that have them or a Mercedes Dealership that handles Sprinters), odds are good you won't find out very much about anything but generic engine errors (and they may not tell you much). Most of the P codes that you will need to know about requires the Sprinter Compatible Diagnostic tools (and those are the P codes that are generally discussed on this forum - Generic ODBII readers codes may not always mean anything to anyone). Some error codes can be ignored.
If you can find someone who has a DAD unit and can run a full scan, that would be great (the ODBII port in the NAFTA Sprinters is right where the drivers left knee is when they sit in the drivers seat). I have done this a few times with my DAD unit (I don't loan it out) as well as reseting errors after work was done (some types of error codes will cause your Sprinter not to work correctly until cleared - many can't be cleared with a generic ODBII tool) .
The parts and service manuals are available for free online for the T1Ns (2002 thru 2006 NAFTA models).
Without knowing your general location, its hard to know if anyone is available with a DAD unit near you (there is a link in this site where people who have DAD units can be found) for you to ask. Please add your General Location to your 'User CP' - in the blue line above the forum entries. It really helps to know.
I bought my Sprinter with no diagnostic check, but it had been recently serviced by a Sprinter service center and it had a clean bill of health from them.