My Toyota Vitz 2007 (also known as Toyota Yaris) key fob battery died about an year ago (The indicator light which comes on when the lock or unlock button is pressed gradually faded away with time).

I didn't replace the battery because it was not possible to open the key without breaking it because it was glued. But, today I bought a new key casing from ebay and cut the old key casing and took out the internal part which has the transmitter. Then I replaced the battery and fixed it in the new key casing.

But, the key fob doesn't work anymore. The indicator light comes up when I press the lock or unlock button, but nothing happens.

What could be wrong here? I read about how to re-program the key, but didn't try it yet because I am not sure what is wrong. Is there any way I can check whether the receiver in the car or the transmitter in the key fob is broken?

  • If the indicator light comes on when you push the button then the next step is to re-code or pair it with the vehicle - there will be a defined set of steps that you need to follow to do this. Either check with a dealer or check in the manual. To actually test the radio transmission etc would involve a lot of expensive equipment.
    – Solar Mike
    Commented Jan 21, 2018 at 21:12

3 Answers 3


I re-programmed the key and it works fine now. Seems like car forgets (may be intentionally) the key code when it has not been used for a while.

Following are the steps I used.

  1. Start with driver door open and unlocked.
  2. Insert and remove the key to ignition twice within 5 seconds.
  3. Close and open the door twice.
  4. Insert and remove the key to ignition.
  5. Close and open the door twice.
  6. Insert key to ignition.
  7. Close the door.
  8. Turn the key to on (Do not start the vehicle) and off (once to add the new key, twice to erase existing keys and add new key). If you followed the steps correctly, the door lock should automatically lock and unlock at this point.
  9. Remove key.
  10. Press both lock and unlock button simultaneously for 1 to 1.5 seconds and release.
  11. Within 3 seconds, press lock button for more than 1 second and release.

You can open the remote by inserting a small screw driver or even you can open it with your nails 🙂 The cell type is CR2016. Replace it and it will work fine


You know what! Same thing happened to me with my Vitz! We replaced the battery and it was still not working. Fortunately, I found that comment from Softcode and followed the instructions. And it worked like magic. A bit on the funny side when we’re doing the steps tho, we look silly opening and closing the doors 😂

  • That answer has already been given.
    – Chenmunka
    Commented Mar 10 at 10:56

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