The ScanGauge II is a fairly light-weight scanner, (i have one, and it did properly report my first Check Engine Light (CEL)) ... it's good for monitoring what's going on when you're driving, and it can report
those problems that the ECU (engine control unit)
is able to forward.
But it's not (anywhere near) a "real" diagnostic Sprinter scanner, which requires talking to the other wires in the connector to delve deeply into the
other computer modules in the Sprinter.
Devices that meet that bar include the Autel 802 (certain sub-models), the iCarSoft system, the laptop-and-multiplexor-based Xentry, the (very limited availability) DAD and the $3000 DRB-III (what Dodge dealers used to use).
I love
my ScanGauge, but it won't tell you what (for example) the transmission's wheel-speed sensors are (mis-)reporting.
If you visit almost any Auto Parts store, they're usually (more than) willing to plug in one of the OBD scanners they sell as a "free scan" to see what it says about your CEL. No purchase necessary.
You can find lists of the Sprinter-specific P-codes (what the scanner will report) here:
http://diysprinter.co.uk/reference
(along with a full 2006 service manual set)
--dick