How to Reset Check Engine Light

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Check engine lights go on when there is a problem in the engine or the emissions control system. You should always have the codes generated by your car's computer scanned and read so you can determine the cause. You can reset the light once you have fixed the problem. This article will tell you how to reset the check engine light in your vehicle.

Steps

Use a Code Scanner

1. 1
   Connect the scanner to the on-board diagnostic connector (OBDII) under your steering column. Turn your ignition switch to "On."

   
   
2. 2
   Press the "Read" button on your scan tool to view the engine's error codes. Write down the code for future reference and repairs if necessary.
3. 3
   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 might have an automatic option and a "Yes" or "Clear" button instead of the "Erase" button.

Erasing the Code (Old Way)

1. 1
   Disconnect your car's battery by removing the positive and negative cables. Use a wrench to remove the cables if necessary.
2. 2
   Press and hold your horn for 30 seconds to drain any remaining electricity from the capacitor.
3. 3
   Wait 15 minutes and reconnect your battery. The codes should be erased which will cause your engine light to turn off.

   
   

Warnings

• Consult a mechanic or repair shop if the code keeps recurring or if you cannot find information on your code or how to fix it. A qualified mechanic might need to look at your car and reset the codes.
• Erasing codes by disconnecting your vehicle's battery can also blow out the memory for your radio and other on-board components. This method is recommended as a last resort.
• The emissions monitors in your vehicle will register being reset, so you will not pass emissions if you bring in a car with the codes being reset. Drive your car for at least 200 miles before bringing it in for an emissions test.

Things You'll Need

• Auto scan tool
• Wrench

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