ihave 2000 buick century. had to replace the battery and now it won't start.?

Question

called the dealer and they mentioned a pass2key system. any body goy any ideas?

Answer 1

Passlock relearn:
Starting with the Ignition Switch in the off position
1 momentarily crank the engine and leave the key in the run position while observing the security indicator.
In 10 minutes the security indicator should turn off. Rotate the key to the off position for five seconds.
Repeat step 1 two more times.
The fourth time the engine is cranked, the engine should start and the BCM and PCM will have learned the new password.

Answer 2

Did you put it in wrong?