No, modern keyless entry systems rely on a somewhat randomized code of fairly significant length.
Check this link out:
http://www.caranddriver.com/features/can-thieves-steal-your-keyless-entry-codes
Excerpt:
According to the lock specialists at Ford, each keyless-entry transmitter has a transmitter identification code (TIC) that is programmed and, therefore, linked to the vehicle. But even if thieves manage to mimic the TIC, the unlocking/locking process is even more complicated.
Here’s how it works: To issue an unlocking/locking action, the transmitter sends a request to the receiver/control module in the car. With the request, the transmitter also sends a new code sequence and TIC to the receiver. To issue an unlock/lock command, the code sequence and TIC sent by the transmitter must be one that hasn’t been used before and the next—or one of the next few—in a planned sequence. This is what is known as a rolling code. And there aren’t just a lot of possible codes; there are a whole buttload of them—4.8 million billion combinations. So even if thieves did manage to steal the TIC and the code sequence from the transmitter, the chance of stumbling upon that crucial next code is one in 4.8 million billion. Good luck with that.
Always wondered how many codes it takes to fill a butt :).
Ok, thanks. It certainly would have been ridiculous if all that was needed to gain entrance to the car was a simple pin code. But you never know these days. :)
I've heard that. Here's my question: I buy a car and get two fobs. I lock the car and take a bus to the other side of town. The wife comes home from a business trip far away and, having had her keys with her (read - far out of range of either the car or my fob) pushes the unlock button and the car opens. How does the car open since her fob cannot know the code used the last time?