Found a little more info for you I dont think its the key but you never know
If i was you I would try the first post I made if that doesnt work here is how to reset the key.............
The Tech II computer is the easiest, but there is a 30 minute procedure.
GM makes it take that long to deter thieves.
Not many of them are going to sit in your car for 30 minutes to steal it.
30 Minute Relearn Procedure
Use this procedure after replacing the following components:
• The PASS-Key III (PK3) keys
• The BCM
• The PCM
Important: This procedure is not available on vehicles equipped with option code (Z49).
If replacing a BCM with an GM SPO replacement part, perform the procedure to setup a new BCM prior to the 30-Minute Relearn Procedure.
With a master PASS-Key III key, rotate the ignition to the CRANK position.
Observe the SECURITY telltale. After approximately 10 minutes, the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
Repeat steps 1-3 two more times for a total of 3 cycles or 30 minutes.
Important: The vehicle learns the key transponder information and/or passwords on the ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
With a master PASS-Key III key, start the vehicle. The vehicle has now learned the key transponder information and the PCM has now learned the fuel continue password.
With a scan tool, clear any DTCs.