Prius Classic -- losing all master keys

It happened to me. I bought my 2002 Prius used about 6 months ago. It came with 1 key. I always knew I should make a duplicate, but it kept getting pushed down on my TODO list. Note to the rest of you, if you have only 1 key left on the Prius classic, PLEASE MAKE A DUPLICATE NOW!!! Even the newer Prius owners need to make duplicates if they're down to 1 key, because it will still cost to the tune of $200-$300 to make a replacement.

Anyway, so I lost that 1 key last week. I searched on the internet, and my heart nearly failed at the thought of having to replace the ECU unit for $2k. I called various locksmiths around town, and finally found a guy who would reflash the ECU unit, at a much lower cost of $500.

He was able to do it. It took nearly 3 hours for him to finish though. The immobilizer unit needed to be reflashed, and it is hidden under the dash, just next to the steering wheel. It was a pain for him to get it out, took another 30 minutes to reflash it, and 30 minutes for the computer to program the key, and another 30 minutes to put the dash back together. But it worked. So there IS another solution, and though it's at a much lower cost than going to the dealer to get the ECU replaced, it is still a non-trivial cost. I have a feeling that the whole procedure of reflashing the immobilizer unit is actually blackmarket, and not officially supported by Toyota (even their dealers won't do it), but it works.

Lesson learned: always have a duplicate key at home somewhere.

 

For the Prius classic, as long as you have the master key, you can buy a transponder key from ebay for around $15-$20, get it cut for a couple of dollars, and program it yourself.

 

Yep, here you go:

1998 1999 2000 2001 2002 2003 Toyota Prius key programming Only

STEPS:
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
Programming Sub Keys (Grey) is done the same way except you turn the master key 4 times
before you open and close the door 5 times. Then insert the sub key, turn to the "ON" position,
and wait your minute. Finish by removing the key and opening and closing the door 1 time as
before.

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
**It is our understanding, according to the book, you can have 2 master keys and 1 sub
key, however, we are aware of one gentleman who was able to program 4 masters and 2
subs.