Hi I purchased a 2009 Accent, 78,000 kilometers and love the car. Bought it last Tuesday. On my way to Winnipeg Manitoba we hit a lot of slush and some bad roads. When I got to our hotel, shut the car down everything was fine. In the morning I woke up fired the car and the check engine light came on.
the guy at the Hyundai dealer said probably the gas cap after about 7 times of 20 minutes of turning off the engine and then restarting it should turn off.

Well the light is on, but it is still totally humid here. Could the humidity be an issue with the sensors. I read that by disconnecting the battery it will reboot the computer?
Scott

 

I've had some check engine light codes come up, fixed them, then the Engine Coolant Temperature Circuit Range/Performance popped up. P0116 was the code. Took the battery ground off and then let it stay off for about 3 minutes. The engine light went out. On the way to Dallas, my transmission decided to shift from overdrive to a lower gear and the check engine came back on again. Took it to a shop and they disconnected the battery ground and out they went and so far hasn't happened again. I don't think humidity would have anything to do with your engine light unless there was water in the fuel. Do you have the code? I hope this information helps.