they won't accurately display most of them.
So (without disagreeing), I would like to ask exactly what this often-repeated statement means.
Does it mean any or all of the following:
(a) there may be codes that are present in the van, but the generic tool will not report at all (i.e., it will report "No codes found").
(b) There exist codes that will be incorrectly reported; i.e., Code xxx will be reported as code yyy.
(c) There are codes that are reported correctly but are accompanied with incorrect interpretations (do any of these tools even provide interpretations?).
(d) There are codes that are reported, but not in sufficient detail to be useful (i.e., sub-codes or parameters are not reported).
(e) something else?
The purpose of my question is to go beyond the generic "don't trust these tools for diagnosis", so respectfully, please don't answer unless you actually know more than that.