I've done this. All you have to do is not have your working key fob with you or near the car. Then you can start all over and make new fob #1
To program a new transmitter to your vehicle when you do not have a recognized transmitter, do the following:
1. The vehicle must be off.
2. Place the new, unrecognized transmitter in the glove box transmitter pocket with the buttons facing to the right.
3. Go to the rear of the vehicle and insert the vehicle key into the key cylinder located on the lower rear fascia on the driver’s side.
4. Turn the key five times within five seconds. The trunk will open.
5. The DIC message will display OFF-ACC TO LEARN.
6. Press the OFF/ACCESSORY button.
7. The DIC will read WAIT 10 MINUTES and will count down to zero, one minute at a time.
8. The DIC will display OFF-ACC TO LEARN again.
9. Press the OFF/ACCESSORY button.
10. The DIC will read WAIT 10 MINUTES and will count down to zero, one minute at a time.
11. The DIC will display OFF-ACC TO LEARN again.
12. Press the OFF/ACCESSORY button.
13. The DIC will read WAIT 10 MINUTES and will count down to zero, one minute at a time.
14. A beep will sound and the DIC will read READY FOR FOB #1. At this time, all previously known transmitters have been erased.
15. Once the transmitter is recognized and programmed, a beep will sound and the DIC will
display READY FOR FOB #2. If you have additional transmitters to program, take transmitter 1 out of the transmitter pocket and place transmitter 2 in the pocket. This can be done repeatedly until up to four transmitters have been programmed. The DIC will then display MAX # FOBS LEARNED and will exit the programming mode. When you are done programming transmitters, press the OFF/ACCESSORY button.
