Battery was removed, nedd the code for music

You need to contact a dealership to get a reset code.

You will have to get that from the dealer... sorry...

4 D refers to 4th gear overdrive for highway driving sustained speeds above 45 mph, 3 D for speeds under 45 mph

that lamp stuck on 4d, means
the TCM sees errors.
so insert the TCM check jumper wire. and see it flash out tranny errors.
check fuses first.
the FSM covers all TCM tests and so does alldata.com

If you've ever lost your radio code for your Honda Accord, you know how frustrating it can be.
You may have to go to your local Honda dealership and pay a fee to have them look up the code for you!
Or, you can take a few minutes to find the code yourself.
Here are 5 methods to get your Accord radio code for free.
Once you have the code, you will need to enter it into your radio to unlock it.

Starter Advice would be, Make sure the vehicle is cold (hasn't been running recently) Take pictures of the mounting brackets & hoses before hand for reference. Then detach hoses & then mounting brackets & replace. Good Luck,

take it too honda and they can pull code for u

The dealer is correct:

But here's a webiste that will help you out. http://www.radio-code.com/Honda-Pay-Page-radio-code-NEW-proced.htm they tell how to remove the radio and wher to find the codes.

Good Luck and tell the kids to hum quietly to themselves until the radio is fixed :)

ALSO, WRITE THE CODE DOWN so if you need to change the battery again, you'll have it. AND for future reference, they make a simple device that you plug into your cigarette lighter socket that has a 9 volt battery attached so when you change the battery, your radio / computer will retain the codes.

A very common problem on these honda's between 1990 and 1992 .The problem is a faulty transmission computer .The location is under the passenger carpet .There are 2 computers there the one on the left is the engine computer the one on the right is the transmission computer this will be what you want to replace!

I don't know if this will work for your radio, but this is what Honda recommends:
Once you have the audio unit serial number, you can call Auto Customer Service at (800) 999-1009 or have the dealer look up the radio code.
Hope this helps you.