Transmitter Resynchronization
WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
If the functions on the remote keyless entry transmitter do not work, or, if only the remote alarm works, after the battery is replaced, then the transmitter needs to be resynchronized to the receiver. Do this by pressing and holding the LOCK and UNLOCK buttons on the transmitter at the same time for about eight seconds.
To verify that the transmitter has been resynchronized, the horn will sound and the exterior lamps will flash once.