Then they started fitting encrypted keys. Part of the data packet was a sort of incremental counter that needs to be kept roughly in step with the car (a typical tolerance was around 30 counts) . This meant that if you didn't regularly use the spare key it lost sync. read more
Just my two cents as don't rely too much on Technology. Human instinct can't replace Technology. All those Safety features in cars , is cool but study shows how many drivers don't pay attention to the alarms when they go off. Another distraction to deal with. Let's keep the car keys simple. Its a key , not your TV remote that controls everything. read more
You can tell if a car has this feature by looking at the ignition key -- the key's shaft has a small black module embedded in it with contacts on either side of the key. It is common to assume that there is some sort of chip or computer embedded in the key. read more