From HybridJDMHonda on SHO

HOW-TO: Resetting your ECU...
Some people claim that resetting your ECU after any sort of modification to your engine will benifit the engine. If it does or how much it does I do not know, but I will tell you how to do it.

There are actually a few different ways to do this, but I have chossen the following becasue it seems to work the best and be simple.

Steps:

1. If your radio/headunit requires any sort of code, and/or if you want to re-program the radio stations you have set write them down on a piece of paper now.

2. Pop your hood.

3. Loosen the negative battery terminal, and pull the cable off of battery connector. Place the cable elsewhere, and make sure the terminal does not come back in contact with the battery connections.

4. Electrons remaining in the system can be purged out through the brake lights by stepping on the brakes, leaving the ECU with no memory.

5. Let the car sit for about a few minutes with the battery disconnected.

6. Re-connect the battery terminal, and start your car. BUT! Do not touch the throttle, just let it set there and idle for five minutes. You can re-program your headunit at this time.

7. Once your car has reached its normal operating temperature turn your car off and then turn it back on.

Thats it!