Hyundai Repair: 2001 ELANTRA GLS, diagnostic code, engine control module

Question
CHECK ENGINE LIGHT ON. FOUND GAS CAP HALF ON (THANKS TO THE WIFE). TIGHTENED CAP. LIGHT STILL ON. IS THERE A WAY TO RESET THE LIGHT WITHOUT A DIAGNOSTIC CODE READER?

Answer
If that was the problem, the lamp will eventually go out on its own, but this will probably take at least two days to occur.  And even then, the diagnostic trouble code (DTC) will remain in the engine control module's memory for quite some time.

You can clear the DTC and reset the lamp by disconnecting your battery for five seconds.