http://www.modifiedlife.com/1990-honda-prelude-car-radio-stereo-wiring-diagram/
The 2005 comes with a five digit (all numbers) code. After the battery is replaced, turn on the radio. The radio should show "Code." Simply punch in the five numbers on the turning buttons and the radio will immediately start working.
Play a different song on the radio
By inserting a 5 digit code into the radio by means of the station preset buttons. If you do not have the code then go to the Honda Owners Link and register your Honda. There you can get the code for free.
Try disconnecting the negative battery wire, leave it off for ~5 minutes, then reconnect. Start the engine. The radio should read "CODE". Using the station preset buttons (1 through 6) enter your code. Then turn the radio on. Works for my '93 Prelude; hope this helps you!
Honda radios have a security feature which prevents their use if they are stolen. This security feature is activated if the radio is disconnected from the battery (I.E. battery in car replaced). There should be a security code in your owners manual. Enter the correct code, and the radio will work. If you don't have the original owners manual, (or you can't find the information), you will have to go to a Honda dealer. They will have to verify ownership of the car/radio and can then look up the code.
I just went through that exact problem with my 88 prelude, it was the ignition cylinder.
Engine bay fuse box (10A Radio Clock)
use a code reader , or take off the negative battery cable off for a few seconds & don't for get to have the radio theft code handy.. after taking off the cable hondas theft system will disable the radio .
The code needed to reset the radio is the model number on top of the radio. The you must call a Honda dealer to get the code. If you are the original owenr or have the owners manual, the code may be in the written in the manual. i need to know how to enter the code on the radio the radio reads ERR 3
You need to enter the code into the radio.
i have a 94 prelude CD player in my 99 civic all you have to do is call Honda and get the security code for the CD player