How to Troubleshoot a Prius Key That Won't Work

Written by lynn anders
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Toyota Prius hybrid cars come with a Smart Key System. Unlike a traditional key that you insert into the ignition switch, the Smart Key is a remote-control device. The key only has to be inside the car for the driver to be able to start the engine by pressing the start button. However, with the convenience of the Prius Smart Key comes the potential problem that the car does not sense the key. If the Smart Key System breaks down, you may be unable to lock, unlock or start your car without using your backup mechanical key (located inside the Smart Key).

Skill level:
Moderately Easy

Things you need

  • Battery

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  1. 1

    Replace the battery in the key. This is the most common cause of problems with the remote Smart Key. The Smart Key uses a lithium battery that can be purchased at the Toyota dealer or jewelry or camera store. Check your owner's manual or consult a Toyota dealer for the battery size your key needs. Access the battery by removing the mechanical key on the side and then removing the back cover.

  2. 2

    Move away from TV towers, power plants, gas stations, radio stations or airports. Since the Prius Smart Key uses radio waves, nearby radios waves and electrical fields can disrupt your key's signal. In these cases, you can use the mechanical key to operate door locks and turn the car on until you are out of range of the disruption.

  3. 3

    Move your cell phone, portable radio, cordless phone or other items that may emit an electrical field three feet away from the Smart Key. These may also disrupt the remote-control system.

  4. 4

    Take the key to a Toyota dealership if the above steps do not solve the problem with your Prius Smart Key. The dealership can replace the Smart Key if the problem cannot be fixed.

Tips and warnings

  • The Toyota Prius 2010 owner's manual reports that "if the battery becomes low, an alarm will sound in the cabin when the hybrid system stops."

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