I am re-posting this info from the 306 Forum coz, I know one day I will need to do this again, and well.....I would just like to know where to start swearing!!!
Read the manual, then try these instructions.
start the vet and back it out of your garage.
Pull the vet back into the garage..leave the vet running.
With the vet still running pull up on the emergency brake.
With the vet still running open and leave open the glove box door.
With the vet still running open the drivers door (and leave open for the rest of this procedure)
Shut the vet off as you normally do. DO NOT GO TO ACC mode.
Press the hatch dash button once to unlatch the hatch. Do not raise the hatch..just leave the hatch unlatched.
Insert the key into the hatch lock assembly and turn the key fully 5 times as fast as you can (ensuring a complete turn each time). Leave the key IN THE HATCH LOCK. You should get a DIC message 'Ready to program FOB.
Go get the unrecognized FOB (should still be 20 ft away) and place the unrecognized fob into the slot in the glove box with FOB buttons facing away from the driver. (I did this in about 10 to 15 seconds from getting the message)
Very quickly (I estimate 5 sec) the DIC will read READY FOR FOB . At this point push the ACC ignition switch. Follow the manual instructions, it will take 2 -10 minute per step.
When programing is complete pull out the newly programmed FOB from the glove box slot and start pressing the newly programmed FOB buttons. At first you may not believe the buttons are doing anything but continue to press them and you will notice the hatch unlocking and the lights blinking (if you have this set up when you lock using the fob).
The new FOB is now programmed. I recommend you place all of the fobs 20ft away and try EACH ONE (not just the new one).
I got this infromation from attach web site. First time I went through the step it said " my new #1 FOB was programed, and when I went to put in my excisting #2 FOB, the dash just skipped it and ask for #3 FOB.
I didnot push any buttons on either New FOB #1, or old FOB #2, I just tried to start the car, and dash said "No Fob in Range"
I though I was Royaly Screwed!
Second time through, I checked each Fob as programing was complete, locked, unlocked doors, light flashed, and everything was working.
So good luck if you need to program a new FOB. Dealership wanted $60 labour, and thats after the $150 for the new FOB.
Programming a new key FOB - HELP - Corvette Action Center