1. Drive Your Car and Let the Light Go Off by Itself:
The first and easiest method for clearing the check engine light is driving and time. Most onboard computers will recheck whatever problem caused the check engine light to activate multiple times. Drive your car as you normally would.
If the check engine light is still on after three days, your problem may not have been fixed or you may need to try some of the methods below to reset it.
2. Turn the Car On and Off Three Times:
Some vehicles will automatically reset the trouble codes that caused the initial error after the vehicle is turned on and off three times in succession. To do this, insert your key into the ignition, turn the vehicle on for about a second, and then off for about a second. Repeat this two more times then drive the car as normal. Check to see if the check engine light reset.
3. Disconnect and Reconnect the Battery:
You will need a wrench. Prop open the hood and use the wrench to disconnect the positive power cable to the vehicle battery. Leave the battery disconnected for at least 15 minutes. Then put your key into the ignition and turn it three times to the “ON” position. This will clear the emissions data from the vehicle memory as well as the readiness flag data.
Reconnect the positive battery cable and turn the key in the vehicle ignition. Wait one minute and the check engine light error should be gone.
4. Use an OBD Code Reader:
You will need a wrench and an OBD (onboard diagnostic) reader. These inexpensive readers analyze and clear engine codes. I have used the Kobra OBD scanner with great success many times for this task.
To perform this method:
Plug the reader into the OBD port of your vehicle. This port is usually located on the underside of the dash area just above the foot well. On some vehicles, you'll have to remove the door on your fuse box to access this port.
Once you have connected the reader, press the "enter" button to turn it on.
The device will scan your engine for any error codes. Once done analyzing, the reader will display any error codes it finds. Make note of the codes (if any) if you wish to cross check them in the code reader's manual or online.
Now you can press the "scroll" button to find the option to erase the code. Press enter while on this option to erase the fault code and reset the check engine light.