Use a Code Scanner
Connect the scanner to the on-board diagnostic connector (OBD-II) under your
steering column. Turn your ignition switch to "On." Turn off all accessories.
Press the "Read" button on your scan tool to view the engine's error codes.
Write down the code or codes in the order they were received for future reference and repairs if necessary.
Press the "Erase" button on your scanner to clear the error code. Clearing any
codes present will turn off your check engine light. Some scanners have other capabilities
like freeze frame that records some sensor readings when a code was set and erasing the codes will also erase this file.
- Some scanners might have an automatic option and a "Yes" or "Clear" button instead of the "Erase" button.
Erasing the Code (Old Way)
Disconnect your car's battery by removing the positive and negative cables. Use a wrench to remove the cables if necessary.
Press and hold your horn for 30 seconds to drain any remaining electricity from the capacitor.
Wait 15 minutes and reconnect your battery. The codes should be erased which will cause your engine light to turn off. This process may not work on all vehicle's computers.
If the battery is disconnected and the light comes right back on, this may indicate an active problem and should be addressed and fixed.