DIY "All In One" Keyfob

I searched several forums and found some aftermarket fobs (with many complaints), so I decided to sacrifice my valet key and try to make one myself. There isn't much of an instruction as you're basically just filing stuff until it fits, but I did learn one helpful lesson about the location of the immobilizer chip, so here are a couple photos.

1. First, I removed the rubber from the valet key and marked how deep the key had to go into the ignition.

2. Next, I removed the metal portion and carefully extracted the immobilizer. This photo shows how much I took off the metal portion of the key, and also shows the original incorrect location of the RFID chip (on the back side of the key) and the new location on the side, where it is in the original key. After everything dry fit, I used 5 minute epoxy to secure the key in place.



3. I made sure to use mylar tape to protect the circuit board from the metal key. Here is the tape stuck to the epoxy after disassembling to fix the RFID location.


3. Final result. You can see how deep the key has to be in the bottom fob housing to clear the circuit board...basically completely filing off the keyring loop of the fob bottom. It may be a tiny bit crooked, but still better than that fob rubbing on my knee all the time.