Jumping in late on this but the first thing you want to do is get it cranking. In doing so you will most likely find why you can't access codes. If The skim theft system was activated it would still allow you to crank and even start and run for 2-3 seconds. Go back to basics(battery,battery terminals ground wire) and find why it won't crank. If you stab a wire and got it to crank you may have a ground issue some where. Somewhere in this diagram is the reason it won't crank;(PCM supplies the starter relay with a ground so if you think it is the PCM then ground that wire and it should crank in the crank position.