Car Security: Immobilizers

Honking horns and flashing lights are old news when it comes to vehicle security. It goes without saying that an auto alarm system will make noise and call attention to itself. But anyone who's sat through a city night listening to car alarms hoot and beep knows that many people -- and thieves -- just ignore them.

That's why the European Community mandated ignition immobilizers on all new vehicles sold after January 1, 1997, and on all registered vehicles as of October 1, 1998. Auto theft costs Americans alone $7.6 billion a year. Worse, particularly in Europe, it has driven insurance premiums high enough to threaten sales of luxury models. The solution: engine immobilizers, security devices that prevent cars from hot-wired or being started without a special key.

Immobilizers have been slower to show up on North American vehicles, but enthusiasm is growing as automakers see results in Europe. Ford, a major European automaker as well as one of the U.S. Big Three, introduced its SecuriLock immobilizer on the 1996 Mustang GT and reported that theft rates fell 77 percent from those for the 1995 model. SecuriLock is now standard on every Ford and Lincoln Mercury model except the Ranger small pickup and the Escort compact, which is being replaced by the Focus. It was added to the Mercury Villager when the minivan was redesigned for the 1999 model year. Cadillac included Delco's PassKey III on most 1997 models, and GM now includes it on Buick Park Avenue, Cadillac Seville, and Pontiac Transport, Oldsmobile Silhouette, and Chevrolet Venture minivans. PassKey III is also included, as the Honda Immobilizer, on the Honda Accord, Honda Odyssey minivan and the Acura CL.

The current movement started in Germany, where, since January 1996, insurance companies have been allowed to hold back as a penalty 10 percent of the theft reimbursement on stolen cars that weren't equipped with immobilizers. An immobilizer system consists of an electronic chip in the key, computers that control the engine and ignition system, and a mathematical algorithm that resets the so-called rolling code to a different series of numbers each time the key is used. When the driver inserts the key in the ignition slot, the transponder reads the code on the chip and relays it to the controller computers. If the code's correct, the computers start the car. The code isn't reset until the driver turns the key to stop the engine. That means that even if someone captures the code with a scanner as the car is started, it won't do them any good; the algorithm most likely will never spit out that particular code again.

Most important, if the controller computers do not receive the correct code, there is no way to start the car. Neither removing the battery to shut down the system, nor hot-wiring past the ignition, nor any other tricks thieves have devised over the years will persuade the vehicle to start without the correct code.

"Immobilization has proven to be so successful in the European market that our customers there have said to stop any further development on any other technologies -- glass-breakage sensor, ultrasonic sensor -- that we were developing right along with the encouragement of our customers," says David Ladd, spokesman for Siemens Automotive, the company that supplies more than 70 percent of immobilizers in Europe.

Siemens was working on the other technologies not so much to prevent intrusion but to prevent the theft of the car, and the immobilizers are largely handling that job. But the growing concern for personal safety means suppliers and automakers are working with both glass-breakage and ultrasonic sensing technologies to detect and thwart potentially dangerous intruders.