As for determining the remote you need the GM or GM/LEAR number need to match. Also I located this process, and it does work just not on all vehicles. The FOB settings can also be in the factory Radio. I had a 2001 monte carlo and the setting was in the radio and came to find out the transmission of the fob signal and the main computer system for it was in the radio. Now this may not be the same on the grand prix but then again never hurts to take a look.
1. Close all vehicle doors.
2. Insert the key into the ignition.
3. Hold down the power UNLOCK button on the driver's door panel-continue to hold down until instructed to release.
4. Perform steps 5 through 8 in fairly rapid succession.
5. Turn the ignition switch to the ON position (as far as you can go without starting the engine).
6. Turn the ignition switch to the OFF position.
7. Turn the ignition switch to the ON position.
8. Turn the ignition switch to the OFF position.
9. Release the power unlock button on the door panel. The vehicle will lock and unlock the doors automatically.
10. Hold down the LOCK and UNLOCK buttons on the transmitter simultaneously until the door locks and unlocks. This step may take up to 30 seconds.
11. Repeatstep 10NOWfor each additional transmitter (including any existing transmitters).
12. Turn the ignition switch to the ON position in order to exit the transmitter programming mode.
Information from - Free Keyless Remote Fob Entry programming instructions, procedures for all automotive vehicles
