Transmitter Resynchronization
WARNING: This page is about a different car, the 2004 Chevrolet Monte Carlo and 2004 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
After you have changed the battery in your transmitter, you will need to resynchronize the transmitter. To do this, press the LOCK and UNLOCK buttons on the transmitter at the same time and hold for about seven seconds or until one horn chirp is heard.