Engine oil

You have to push the rest button

Make sure oil sending unit is plugged in, if it is, replace it. If problem continues, check oil pressure with a manual gauge

I realize this is 4 years old, but for future reference you need to reset the oil change light after you change the oil. There's no "button", the procedure is to turn the key on but don't start the engine, and then push the gas pedal down three times quickly. The light should now be flashing to tell you its been reset and you can now turn the key off. Next time you start the car the light should now be off.