have you ever needed to put the code in before? if this is the first time you have disconnected the battery then the code you have (if its in your manual or whatever is wrong)...if you have typed the code before then just disconnecting the battery wont of altered the code, it does say in the manual that you have to hold the PTY button but i never had to do that ...this is why i assumed it was the wrong code.
i had the wrong code in mine and i had to go to the dealer for them to find me the correct code as they totally screwed around with the manuals
after you tried this you have got to wait AT LEAST an hour with the ignition on to re do it