ok the check engine light just came on. and i took it to advance to have it scanned. and it said something like engine over temp. then i thought about it and before i drove it i took off the radiator cap and check the coolant. i put it back on but after that thats when the CEL came on and that code came up. what could be the cause they said the thermostat. which i don't mind replacing but the maximas run about $45 and was wondering if there was soething else that could cause it to read that. how do i reset the code?