Transmitter registration
1. Turn the ignition switch to the "OFF" position, press and hold the door lock button. Turn the ignition switch to the "ON" position "ON" → "OFF" → "ON" → "OFF". Release the door lock switch. Make sure the locks operate once.
2. Press the "LOCK" and "UNLOCK" buttons simultaneously for 15 seconds. Make sure the locks work once.
3. Repeat step #2 for each transmitter you add.
4. Turn the ignition switch to the "ON" position to exit the transmitter registration mode.
Transmitter synchronization
1. Synchronization is performed in the following cases:
- the battery in the transmitter has been replaced;
- the wire was disconnected from the battery terminal;
- the button on the transmitter has been pressed more than 256 times.
2. Lock the car.
3. Press the "LOCK" and "UNLOCK" buttons on the transmitter simultaneously and hold them for seven seconds. Make sure the door locks work.
The article is based on data from the website ChevyMan