I know this is a really old question but I just reset the factory stereo in my 1994 Integra and figured I could contribute some useful info. If you don't have the original manual you can look for a white sticker with two numbers on it. The top 5 digit number is the radio code and the lower one is the radio serial number. I've seen the sticker on the outside of the glove box on the left side. I found mine on the bottom of the ashtray after I removed it to clean it out. If that doesn't work your only option is to have a Honda/Acura dealership give you the code for your specific car (based on the VIN number).