Find the jumper harness underneath the passenger side dash, by the door. You might have to reach a bit for it, it has a green rubber cover on it. Pull off that cover to expose the blue harness. Take a paperclip or short piece of wire and plug it into the back of the harness, connecting the two terminals with the wires going into the other side. Turn your car to on. Count the number of flashes. Each long flash counts as 10, and short flashes count as one. For example long-long-short is a code of 21.

http://hondata.com/techecucodes.html

Here they list all the codes