How to Repair a Prius Smart Key

Repairing a Prius smart key is usually an issue of programming. Lost or inactivate smart keys must be reprogrammed to activate their functions. This generally requires the use of specialized diagnostic tools that are available only at a Toyota dealership. You can perform the job yourself as long as you have one original key fob. Performing a series of steps will allow the smart-key fob, which has a silver Toyota logo on it, to operate the ignition and door locks, and remotely unlock and start a 2004 to 2009 Toyota Prius.

Starting the Prius

• 1

  Insert your old fob into the ignition slot, then remove it. Do this four more times in a row, leaving the key fob in the dash the fifth time.

• 2

  Open and close the driver's door six times.

• 3

  Remove the old original key fob from the ignition slot. The Prius is now in fob programming mode.

• 4

  Insert a new fob into the ignition slot. Leave it inserted for 60 seconds. Watch the blinking red dashboard light until it stops blinking. At that point, the new fob is programmed.

• 5

  Remove the new fob. Test both fobs to double-check that they work correctly.

Remotely Unlocking/Locking the Doors

• 1

  Open the driver's door.

• 2

  Insert your original fob into the ignition slot and remove it. Do this twice within five seconds.

• 3

  Close and open the driver's door twice.

• 4

  Insert and remove the original fob once. Close and open the driver's door twice again.

• 5

  Insert the original fob and close the driver's door.

• 6

  Press the Prius power button without pressing the brake pedal. Wait one second, then press the power button a second time. Wait one second, then press the power button a third time to power off the car.

• 7

  Remove the original fob from the slot. The Prius is now in "add mode." The Prius should lock and unlock the doors twice to signal that "add mode" is active.

• 8

  Press and hold both buttons simultaneously on the new fob for one and a half seconds. Within three seconds, press the fob's lock button. The Prius responds with one lock/unlock sequence if programming is successful. If the car locks and unlocks twice, the programming was successful.

• 9

  Exit "add mode" by opening the driver's door or inserting the fob into the ignition slot.