OK, well I solved this issue. You cannot take the key apart or replace the chip without major surgery. I bought a key from a wrecked car and destroyed it to find out what was inside and how to take it apart. Here's how to split open the case:
1. Drill out the pin shown below and pull it out. It's locking the entire case. You could also use a hammer and very thin punch to push it through the plastic wall that's on the other side. It may also be possible to drill from the other side and then push the pin out. As long as you drill straight it won't hit the chip inside. Mine is crooked because it bent when I pried the case open. It cracked the plastic pin keepers holding the metal pin and in my case also split the key fob sides. You may also be able to drill the plastic pin keepers holding the metal pin down by drilling two holes just to the left and right of the pin. That should weaken the plastic pin keepers so that they'll break first when you pry the case open.
2. Once the middle pin is removed (or you're ready to give it a crack, literally), pry the case open at the metal key end. The other end (key ring end) has a hinge and it will open like a clam shell. There are some short hooks holding it together but they'll come apart easily.
That's it!
Biggest difference in internals is that the immobilizer chip is no longer a separate pill that's glued to the plastic. It's now part of the circuit board and the solder points are covered with glue. The immobilizer chip long black rectangular chip. If you separate the chip from the board it won't work. This is unlike the older keys which had a separate immobilizer pill which worked independently. I believe this design change was to give additional range for KESSY. The good news is that if the remote battery is dead, the immobilizer chip will still work - you just have to hold it next to the ignition switch blank off plate to pass the signal. So if you want to replace the chip, you'd have to figure out what and where to buy a replacement chip, remove the glue, desolder it and solder in a new one. IMHO, way too much trouble for the amount of time and money saved. Like the last few types of remotes, once a chip is programmed to a VIN, it will only work for that VIN. It cannot be programmed to another car. Since the remote half and immobilizer chip are on the same circuit board, there's no use for a half key, unlike earlier cars.
Therefore, I will change my recommendation for the new mk6 style keys to: if it's broken, go out and buy a new one. The only case where you may reuse it is if the key loop or metal blade is broken, and even then, it's a huge pain to split it open. The good news is that if you drill or punch the pin out, the clips are strong enough to hold the key together. The pin was put there to lock the case down.
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