We lost one of our Ignition Transponder Key to our 2002 Prius. Toyota wanted $36.21 for a blank key and an additional $105 to program the key. I took our good key to Henry’s Hardware in Kingston and had them cut and program a new key for $69 however the key did not open the locks or turn the ignition. No charge. I found and ordered an Uncut Un-programmed Transponder Ignition Chip Car Key on Ebay for $6.24 which included shipping.
I took this Uncut key to Coast to Coast Hardware in Poulsbo and they cut it but it would not open the doors but did rotate the ignition but the programming did not work. They cut another key which did open the doors but had no Transponder so could not start the engine. They charged $11 for the two keys.
I was eventually able to program the Transponder Key using the below program so now all works however I need two keys instead of just the original one key. We did not loose a FOB Remote so we could use that with the new Transponder key and all should work fine.
The below key programming worked. (From https://www.coastaletech.com/keys.htm)
This is something you can do yourself and really only takes a little more than a minute.
1. Begin by sitting in the driver seat with all the doors shut.
2. Insert your working master (black) key in the ignition.
3. Very Quickly, turn the key from "LOCK" to "ON" 5 times. (You will end with the key in the "LOCK" position)
4. Immediately, open and close the driver door 6 times very quickly. (End with the door closed)
5. Immediately, remove your working Master Key and insert your new Master Key
6. Turn the key to the "ON" position and leave it there while you wait for 1 minute.
7. After the minute, if you want to program another key, just remove the first one and insert the next one, turning it to "ON" and leaving it in position for 1 minute.
8. When you are through programming keys, just take the last one out, open and then close the driver door to lock in the programming, and your done :)
You can erase all the keys and start over by turning a working master key 6 times and then opening and closing the door 7 times. Then remove the key and reprogram again.
Remember : You only have a few seconds to perform each maneuver so don't waste time. You will know when you have done it right when you insert the blank key and the security light on the radio stops blinking. If it does not work, try completing the sequence faster, time yourself. And don't worry, if it doesn't work the first time, just do it again :)