When I took delivery of my C8 it appears that Bowling Green (or the shipper) mixed up keyfobs. I didn't realize it until I got home.
The silver one worked fine but the black (outline) one did nothing and it was obvious that the mechanical key was different.
I contacted the dealer assuming the keys got mixed up with another inbound unit but they only got one in.

I brought it in and the dealer had ordered another silver key. The programmed the new silver key as #1 and the old silver key as #2. They gave me back the non paired black one so I didn't ask them to reprogram it because I assumed I could do it at home and just buy an uncut key and thus have 3 keyfobs.

Following instructions in the manual (two working silver keys on seat and the black one in the cup holder) I attempted to pair the black one as #3 and got an error. At first I thought I had a huge problem because the C8 couldn't be turned off, the original keyfobs stopped working and I was wondering what I was going to do. I wound up clearing the DIC, removing the non-working black keyfob from the car and then the vehicle recognized the two silver keyfobs again.

Is there anyway I could do one of the following:
1) reprogram the black outline key as #2 and one of the silver keys as #3 (I am betting this is a dealer only deal)
2) clear and reprogram the black outline key as #3

Thanks!!

 

That is a good and useful question. Unfortunately I do not have an answer. Having gotten a new key fob for another GM product, only the dealer or a authorized locksmith could do it. Maybe you could do it if you wanted to buy some very expense equipment and/or software to be able to program fobs and cars.

I mostly responded to follow the thread to see the answer.

 

maybe you need to keep the 2nd working key away.