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How to Clear GM Codes

by Dwight Malone

No matter what kind of GM vehicle you drive, odds are at some point, a trouble code will be triggered and the check engine light will go on. This is your vehicle's way of telling you something is wrong and it needs to be taken care of to avoid further damage. While an engine code can be an indication of severe mechanical failure, it can also caused by minor issues. Once you've resolved the issue, the engine code will need to be cleared. The process for doing this is the same, regardless of what GM make and model you drive.

Open the hood and locate the battery on your GM vehicle. Placement varies depending on your specific model. Generally, the battery is located in one of the four corners of the engine compartment.

Use the adjustable wrench to loosen the bolt holding the negative battery clamp on the negative terminal. The negative clamp will be identified with a minus sign and will be connected to a black cable.

Wait at least 30 seconds with the negative battery cable disconnected.

Reconnect the negative battery clamp to the negative battery terminal and tighten it until it is secure and cannot be wiggled with your hand.

Start the vehicle and check the instrument cluster on the dashboard to confirm the check engine light is off. If the check engine light is no longer on, the engine codes have been successfully cleared.

Tips

  • If you prefer to not have to get under the hood and disconnect the battery, the codes can be cleared by using a OBD-1 or OBD-2 scan tool. The OBD-1 is used for 1995 or older GM vehicles and the OBD-2 is used for 1996 and newer vehicles. You can take your car to your preferred auto parts store, which will have the scan tools and can clear the codes from your vehicle free of charge.
  • Disconnecting the battery will clear out your car's clock and radio presets, so upon reconnecting the battery, you'll have to reprogram both.
  • If you have a GM vehicle with dual batteries, such as a 1994 Chevrolet Suburban Diesel, you only have to disconnect one battery to clear the codes.
  • If the check engine light is still on after disconnecting the battery, disconnect it again and wait for a longer period of time before reconnecting it to ensure the codes clear out.

Warnings

  • Always be sure the vehicle's ignition is in the off position when working on the electrical system to reduce the chances of getting an electrical shock.
  • When removing the negative battery cable, take extra caution to not let it touch the positive battery terminal, which can cause a spark.

Items you will need

About the Author

Dwight Malone is a journalist who has worked for various Chicago-area newspapers, including the "Chicago Tribune" and "Naperville Sun." He has been a writer, editor and graphic designer since 2000. Malone studied journalism at Eastern Illinois University.

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