For 1990-2009 cars

Perform the following steps to synchronize the transmitters:

1. Stand within the vehicle operating range of 30 feet (9 meters).
2. Press and hold the LOCK button and within one second, press and hold the UNLOCK button.
3. Continue holding both buttons for approximately five to ten seconds and then release.
4. If the transmitter was out of synchronization, it should function properly.