Originally Posted by jeepxj19
i went to a local place cause my check engine light was on, and they gave me a reading and printout for free. i beleave autozone offers this aswell. just have them print out the code for you.
If you are talking about the vehicle listed in your avatar its because your truck is OBD-II which is a standardized system, unlike OBD-I.
You can't do what you did with most OBD-I vehicles.