lockpro,
The only "reasonable Diagnostic tool" for your 2007 is the factory service diagnostic tools at your Mercedes Benz/Dodge/Freightliner dealer.
They are far too expensive for private owners, and seem too expensive and specialized for most independent shops.
The least expensive way to diagnose your 2007 Sprinter is to take it to the dealer and have the factory trained Sprinter techs run the diagnostics and
make the repairs.
The factory Sprinter techs also have resources within Mercedes Benz that are not available to non-authorized shops.
You do not have to authorize any work, but from many of the stories here on this forum, it seems some folks spend far more replacing things that
don't need replacing...to avoid having the dealer get the whole diagnostic report and then fix only the items that require it.
There are some cheap "clones" of the MB SDS system, but they feature pirated/stolen software and often do not work all that well.
Plus, even if you have the MB SDS system, you would need to go to a class for several weeks to really learn how to use it in the same way the
factory trained Sprinter techs @ your friendly Mercedes Benz authorized dealer/repair shop.
Develop a good relationship with a MB dealer that has the factory trained technicians and it could lower the cost of ownership of your Sprinter to
the minimum possible.
Roger