The best way to reset your car’s computer or clear it of engine error codes is to use a code reader. If you do not have one on hand, however, you can reset the computer with this procedure.
To clear the computer, you must remove all power from the system so that the codes are “forgotten”. You do this by simply disconnecting current power and then grounding out whatever power is residual.
Remove both battery cables (positive and negative) and then connect them together. You can do this with electrical tape, zip ties, or clamps. Keep the cables away from the battery terminals (using a bungee, you can “hang” them from the open hood as an option) and let them remain connected for at least half an hour.
Clean all terminals and connectors thoroughly (water and baking soda work well). This should take five or ten minutes if done thoroughly. Then reconnect everything (about 40 minutes have passed at this point) and start the car again.
No codes should be present as the system has been drained completely. Be aware that you will likely lose presets and other non-permanent data in your stereo and accessories.
If codes continue throwing, you may have a more serious problem.