Car Talk: New technology makes car theft difficult but not impossible

Dear Car Talk:

How vulnerable to theft are push-button start cars? I’ve heard thieves can copy the signal of the key fob.

Realistic possibility or “Mission Impossible” fantasy? — John

A little of both, John.

First, you have to understand that car theft is a cat and mouse game that will probably never end.

Every time thieves (whose full-time jobs, remember, are being thieves) get around the latest anti-theft technology, car manufacturers — encouraged by insurers who actually pay the stolen car bills — add new technology to foil the thieves.

Rinse, lather, repeat.

Overall, car thefts have dropped dramatically over the last 30 years —they’re about a third of what they were in 1990 — although they’ve inched up a bit in the last few years.

Most of this drop is attributable to immobilizers. Most car makers put a computer chip on the key. And unless the car’s computer recognizes that specific computer chip, it won’t allow the car to run. That put the hot-wiring crowd right out of business.

Push-button ignition works by storing a code in both your key fob and the car system’s computer. Unless the car is able to read that code from a paired key fob, it will be immobilized. And the key fob has to be within a few feet of the push button-usually inside the car.

Now, some enterprising thieves have purchased devices that can read (aka steal) and amplify a key fob’s signal. One device steals the signal, presumably from outside your front door, a few feet from where your key fob hangs on a hook. It then transmits that signal to a second device held by another thief standing next to the car. And that second device transmits the code to the car. This is explained in detail on a number of websites — that, just by coincidence, sell steering wheel locks.

Anyway, car makers are already striking back, with some using a wider band of frequencies in key fobs than the thieves’ devices can detect. Other manufacturers set their key fobs to go into a “sleep mode” when they’re not being used, so no signal comes out of them when they’re not in use.

And the truth is, some manufacturers try harder to prevent theft and implement new, anti-theft technologies faster than others. You may have read about the recent rash of Kia and Hyundai thefts, where teenage thieves discovered how easy it is to steal one of those cars with a screwdriver, due to a lack of immobilizer. Hyundai and Kia say they’re adding immobilizers to future models — but suggest current owners buy a steering wheel lock and a 140-pound Rottweiler.

Anyway, it’s always possible for a thief to steal a car. But it’s certainly a lot harder than it was years ago. And the cat and mouse game will continue.

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