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How to Reset Sienna Codes

by Dwight Malone

At some point, odds are the check engine light in your Toyota Sienna will come on. The check engine light turns on when the Sienna's internal computer identifies an error code, signaling an issue somewhere within the Sienna's mechanical system. A code can be triggered a number of things, ranging from a gas cap that hasn't been tightened properly to something more severe, such as major engine distress. Whatever the problem, once it's fixed, the codes will need to be reset and cleared from the Sienna's computer.

Turn the Sienna off and remove the key from the ignition.

Pull the hood release lever, located under the left side of the dashboard.

Depress the hood release latch under the front of the Sienna's hood and open the hood.

Find the battery. It is a square box and is located on the front driver's side of the Sienna.

Remove the negative battery cable from the battery. Loosen the bolt on the negative battery clamp on the negative battery terminal. The negative terminal is marked by a minus sign.

Wait for up to a minute with the negative battery cable disconnected. By removing all sources of power to the vehicle, this clears and resets the codes in your Sienna.

Reattach the negative clamp and use the adjustable wrench to tighten it down.

Put the key in the ignition and start the Sienna. Wait for all other warning lights to go off. Confirm that the check engine light is no longer illuminated. If the check engine light is still on, you didn't leave the cable disconnected long enough. Disconnect the negative cable again and this time extend the wait time to be sure the codes clear out.

Tip

  • If a mechanic is performing the repairs, they will clear and reset the codes. You will only need to clear them yourself if you are doing the repair on the vehicle.

Warnings

  • Never touch the positive and negative cables. Doing so could cause a dangerous spark, electrical short or explosion.
  • Keep any flammable liquids away from the area you are working in to prevent any sparks from causing an explosion.

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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