With the vehicle off, remove the positive battery cable for about 10 to 20 seconds then put the cable back on the terminal of the battery. If the check engine reappears then there is another problem with the car.
Addition:
Although the above procedure may work, another alternative would be to check what is causing the Check Engine Light to come on using a scan tool or code reader. You can get a code reader pretty cheap at most auto parts stores, and some stores will even lend you a scan tool to check what the codes are, and some will do it for you at no cost. That way you will at least know what is causing the issue and have a chance of fixing it if the light does come back on.
If the check engine light is blinking that means an engine cylinder misfire has been detected
Disconnect the battery for approximately two minutes.
Have vehicle scanned to determine the problem and have codes cleared
unhook the positive on the battery for 5 min. This should reset your check engine light if it doesnt then you still have issues.
it can be of all stupid things a improperly fasstened gas tank cap
How do you reset check engine light for the 2009 Chevy trail blazer?
No, it comes on for an issue that causes an increase in emissions. See related question below.
If the check engine light is flashing off and on when the engine is running that means an engine cylinder(s) misfire has been detected . You need to have the vehicle scanned for any trouble codes to help diagnose and then repair the problem
There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.
disconnect the battery for 30 seconds
You can either bring it in to a Chevy dealer or use a programmer/tuner to reset the check engine light.
sounds like a possible bad idle control valve. is your check engine light on? if so get it scanned for free at autozone