I posted this in an other 100 series key thread recently:
This is how I successfully replaced a lost key on my 2005 for $22:
After reading the FAQ and numerous threads that lead me down not quite the right path, I wanted to report back with what worked for my '05. Hopefully this saves you some time as I spent an awful lot of time with some trial and error. For successful full key with transponder and fob replacement, I ordered part #HYQ12BBT - 4D67 Chip for under $20 on ebay. This was after ordering the same part # with a "G" chip which is not compatible with my "Dot" or "D" 4D67 chip. Apparently there is also a "H" chip so you need to look at your existing key for a "G", "H", or a circle which is the dot key.
Next go to Ace or your locksmith and have the key cut for $2 (a buck a side). Ace was unable to program my key as their system registered errors, so I manually programmed both the fob and transponder.
Successful fob programming steps for door locks:
1. Begin with the key out of the ignition.
2. OPEN and UNLOCK the DRIVER'S side door. CLOSE all other doors including the trunk.
3. Within 5 seconds INSERT the key into the ignition and PULL it out TWICE.
4. CLOSE then OPEN the DRIVER's side door TWICE.
5. Insert key INTO the ignition then REMOVE it.
6. CLOSE then OPEN the DRIVER's side door TWICE.
7. Insert the key INTO the ignition and LEAVE it in ignition.
8. CLOSE the DRIVER's side door.
9. Switch the ignition to ON then OFF.
10. REMOVE the key from ignition.
11. The door locks will now cycle to confirm the vehicle has successfully entered programming mode.
12. PUSH and HOLD the LOCK and UNLOCK button for 1.5 seconds on the first remote being programmed. As soon as you let go PUSH the LOCK button and HOLD it for 2 seconds.
13. The door locks will cycle to confirm successful programming of the remote. If you have any additional remotes to program repeat step 12 if you have no additional remotes proceed to step 14.
14. OPEN the DRIVER'S side door. Programming is now complete.
Successful transponder programming:
1. Start with all doors closed
2. Insert and then remove master key in the ignition cylinder 5 times, leaving it inserted on 5th time.
3. Open and close driver's door 6 times, leaving it closed on 6th time.
4. Remove master key from the ignition cylinder. Verify security light is continuously illuminated.
5. Insert new key into ignition cylinder. Security light will blink for 60 seconds then extinguish.
6. Remove key from ignition cylinder, open driver's door to cancel programming mode.
7. Test operation of new key by validating response of security light to a master key, and starting the engine.