If your "check engine" light is on in your Honda, you should have the engine checked by a qualified mechanic. But after the car has been checked and possibly repaired, you will want to have that light off. Also, if you are taking your Honda to have a state emission test, you will want to have the light turned off so the car can pass emissions. The check engine light is not the same as the "maintenance required" light, which automatically comes on at set mileage to remind you a factory-recommended service interval has been reached. Sometimes when the check engine light comes on, for whatever cause, the light doesn't go off when the cause is rectified. You can turn it off yourself.
Located the fuse box panel cover on the side of the dashboard. Open the panel by pulling down on the top.
Look for a sticker on the back of the fuse panel cover that shows the list of all the fuses and how they are arranged. Find the "clock" fuse, which is probably fuse 13. Remove it using the fuse puller. If you don't have a fuse puller, you can pull it out with tweezers.
Wait about 30 minutes, then put the fuse back in place. This will reset the check engine light and turn it off.
You will need to reset the clock in the vehicle.