with the radio off....hold the 1 & 6 buttons while turning the radio on.
Then release & it will flash both sets of numbers. write them down. then you will have the units serial number. You can ask any Honda dealer for the anti theft code & compare it to what you have on your card. If it's different, then the head unit was replaced at some point OR you were given the wrong card. Some cards may have the serial number on it. If so, then you can compare it to the one you retrieved.
This is how to get the serial number on newer models without needing to remove the unit. It's good for some 01, 02, most 03 & newer Hondas.
