Aston Martin DB 9 2010 Manual page 27

The vehicle must be within operating range of the garage door
opener and the ignition set to ON. Make sure you comply with the
safety instructions even when synchronizing the rolling code.
1. Locate the Training button (programming button) on the garage
door opener motor head unit. Exact location and color of the
button may vary by gate or garage door opener brand (refer to
the operating instructions of the garage door opener 'Training
additional remote controls').
2. Press the Training button (programming button) on the garage
door opener motor head unit (which will usually set a 'training'
LED to ON).
Following step 2, there are typically 30 seconds in which to
initiate step 3.
3. Firmly press and release the programmed HomeLink button.
Press and release the HomeLink button a second time to
complete the training process. (Some garage door openers may
require this procedure a third time to complete the training).
The garage door opener should now recognize the HomeLink signal
and operate when the HomeLink button is pressed.
The next two buttons may now be programmed if this has not
previously been done (Refer to 'Programming', page 2.15).
Reprogramming
If a HomeLink button has been programmed to operate a device, and
you now wish to use this button to operate a different device,
proceed as follows. This procedure will erase the existing
programming of the respective HomeLink button.
1. Press the appropriate HomeLink button 1, 2, or 3 which
requires reprogramming and keep holding it for about 20
seconds until the LED starts flashing slowly. Do not release until
step 4 has been completed.
2. When the LED begins to flash slowly (after approximately 20
seconds), hold the remote control of the device you wish to
train approximately 4-12 in (10-30 cm) away from the
HomeLink transmitter unit - keeping the LED in view.
2.17