I need to unlock my 2004 Honda civic rodio code

There is no default code, try the following.

1. Look in glove box for small sticker with numbers, should be 5 digits with numbers no greater then 6.
2. Pull out the ashtray and see if the sticker is on the back of there.(older models that have them)
3. Pull radio from dash and write down radio serial number and call local dealer with that number and they will be able to get the code for you. They will ask verifying questions.
4. If you happen to have all the books from the dealer look in the 'HONDA SERVICE HISTORY' book, NOT the owners manual. It should be on the first page in the AUDIO CODE box.

The dealer can not give you the code for the radio with your VIN unless you purchased the car from the dealer and they still have your info on file. If they charge you it's because they will do step three above.

Some say if you turn off radio and hold the 1 and 6 preset buttons then turn radio on it will give you the serial number. I hope this helps. If not, let me know so that I might be able to try again.