Thanks Froggy for all the support you are giving to the project. I have been busy as of late, but quickly glancing through your discussion the only two things I thought of were:
1) What Arduino IDE version is being used to compile the program with? I always used 0015.
2) Check the hardware!
Make sure that 510 ohm resistor is in there correct.
Also, Which is more likely, I did some quick googling and found this line that peeked my interest:
"At a software level, ISO14230 is a vastly extended ISO9141-2 protocol that supports much longer data frames and much quicker communications startup with the ECU. "
I think that might be a clue to what is going on.
What we need is an accurate document of the 14230-4 protocol so we can revise the code accordingly. If someone could find that before me, that would be great!