most "generic" odb2 readers wont get you much more than the code number
(if that, in some cases)...
in order to properly diagnose problems you need to be able to TEST
& "communicate" w/ the mfg data that is in the "extended range"
(ie: specific to FORD/PSD etc...outside the function/capablity of "generic"
readers.)
Knowing the code number just simply isnt enough to properly diagnose
a problem...a code number can be generated by an upstream or downstream
part failure...you can not REASONABLY rip & replace a part based on
a single code number.
as an example egr/ebp/vgt all work hand in hand...the failure of ONE
of these items can generate MULTIPLE codes...w/out being able to
TEST (w/out removing) a part is a HUGE time & money saver...
AutoEnginuity has a GREAT PC or Palm Based system...im VERY happy w/ it,
its upgradeable (for free) its good for MORE than one car or truck...