What does the main't required light on a 2003 Honda Civic ex mean?

If it has a separate "change oil" light, you probably have a problem that needs correcting. The computer turns on one of those lights if there is a problem code that needs to be read and resolved. Borrow, rent or buy a code scanner to find out what's wrong. The computer will tell you everything you need to know.

The 2003 Honda Civic EX does not have a separate "change oil light". The maintenance required light is essentially the oil change interval light. There is another light that has a picture of an engine on it, that is the trouble code light (also serves as dire warning light.)

Check your owners manual for symbol meaning.

To reset the maint light, I am searching for a good answer. A bad answer is to disconnect the battery and touch the two cables together to reset. Its a bad answer because you then have to reprogram the driver side automatic down window and the engine needs to "relearn" its idling characteristics curve. Both procedures are annoying, best to avoid if you can.