2005 Toyota Avalon LimitedClick to enlarge picture

The Toyota Avalon offers a key-free system for buyers of the top-of-the-line Limited model.

You might wonder, given the hands-free, "smart key" feature appearing in more vehicles at auto shows and at dealerships.

Known by several names such as Keyless Go and Smart Key, the new technology is already offered on the Cadillac STS and XLR, Mercedes-Benz S-Class, E-Class and SL-Class, Lexus LS 430, Toyota Prius and Avalon and Infiniti M, among others. It lets drivers unlock cars by just walking up to them and touching a door handle. Drivers don't need to push a button on their vehicle's key fob or even take the fob out of their purse or pocket.

Meantime, these drivers can start their engines simply by touching a button on the dashboard. Their new, sophisticated fob device automatically communicates with the car. All that's required is the fob must be somewhere inside the car.

Evolution of Key Fobs

Many automaker officials describe this keyless entry and startup system as a convenience for drivers. It can incorporate many features, including remote starting.

"I think we looked at it as a way to make the process of getting into a car easier," said Patrik Borenius, department manager for advanced product planning at Mercedes-Benz USA.

Mercedes, which is a pioneer in what it calls Keyless Go technology, offers the system on at least five 2005 vehicles, which is more than any other carmaker.

Option price is more than $1,000 on a Mercedes S430, but it's just over $900 on Toyota's Prius. In the Infiniti M cars, it's standard.

Other carmaker officials say the keyless systems also can make consumers feel they have neat new technology in their new vehicles.

"Everyone has remotes, which have to be aimed at the car [to open it]," Borenius said. "We felt that this was the next step. We said, 'Imagine that there are no locks.' So we created this technology . . . People are very positive about it."

Someone rushing to get inside a Mercedes E-Class wagon in a heavy rainstorm won't need to fish out a fob from his pocket and press a fob button to unlock the car. And a parent carrying a youngster won't need to put the toddler down in a parking lot to dig around at the bottom of a purse or in a pocket for the fob so the adult and child can get inside an S-Class.

Indeed, Larry Holman, engineering group manager for electrical vehicle access, at Cadillac's General Motors Corp., said smart key systems can "provide a 'wow factor' for the customer. It's something new and exciting."

An Engineering Feat

But this new convenience feature also adds a new level of complex engineering.

For example, seven antennas are in the new top-level Avalon Limited sedan, helping the standard Smart Key system operate, according to Paul Williamsen, curriculum development manager at the University of Toyota.

Though these antennas use a radio frequency to operate, they have nothing to do with the car's radio, he noted. The seven antennas are in the Avalon only to communicate with the Smart Key fob that the driver can carry in a pocket or purse.

Four of the antennas are found in the doors—one in each door so a driver can walk up to any of them and open just that door. There's another antenna in the trunk lid to detect if the driver walks up to the trunk and wants to open it. There's a sixth antenna inside the car that senses it's okay to start the engine when the Smart Key is in the vehicle, and there's a seventh antenna that's a safeguard. It's designed to detect if the Smart Key might happen to be mistakenly placed or left inside the trunk. If this occurs, the trunk lid pops open on its own so the driver can retrieve the "lost" Smart Key fob.

Toyota isn't the only automaker going to such lengths to get away from traditional keys.

In engineering the Keyless Access system found on the Cadillac STS and XLR, engineers made sure the cars routinely check the battery strength of the new fobs because they are so critical, said GM's Holman. So, when a battery gets low in an STS fob, the driver is alerted via a message on the dashboard, he said. As a further backup, Cadillac still provides what it calls "mechanical key access" to the vehicle.

But Toyota's Williamsen said it's up to a driver of the Avalon to notice if a fob battery is weakening, which likely will show up as a reduction in the working range of the fob. "As a backup, if yes, the battery gets weak and doesn't work from two feet away, in a pinch, you can hold the fob right next to the door handle and it will open the door," he said. This is because the little, shiny silver-colored Toyota logo on the fob incorporates part of an antenna, he said.

Some Interesting Situations

But there still could be snafus.

Williamsen said an early Toyota smart key application a few years ago showed "occasional interference" when cars were at or near some Exxon and Mobil gasoline stations. It turned out the stations had cardless pay systems which "flooded" their locations with the same radio wave spectrum that the autos were using.

"You only lost a small functionality" but it was enough to require changes, he said.

Meantime, GM engineers realized there are rare spots—at some military sites, near broadcast towers and by airports—where a car could be "in a severe RF [radio frequency] environment" that could affect the Keyless Access system, according to Tom Dutter, lead engineer for Keyless Access. So, they installed a "high-power" bypass inside the car to ensure a driver isn't stranded, he said.

Many tech-wary consumers might wonder if it's all worth it.

But Dan Bonawitz, vice president for corporate planning and logistics at American Honda Motor Co. Inc., said electronic features are growing, in part because the cost of such technology is lower than ever before. Honda's Acura luxury line introduced its first car with a standard Keyless Access system for the 2005 model year.

It's the Acura RL sedan and is a bit different from others because there's no start button on the dashboard. The RL has something that looks like a key stub that has to be turned, just as a driver would turn an ignition key. But the RL's stub doesn't have a slot for a key to be inserted.

Auto industry officials also cite competition for the proliferation of new technology in cars.

"We saw [hands-free entry systems] being implemented in Europe and we anticipated it coming to the U.S. market," Dutter said, explaining how the XLR debuted as a 2004 model with Keyless Access.

With the exception of the Prius, which is a gasoline-electric sedan with a starting manufacturer's suggested retail price around $21,000, most vehicles offered with a smart key feature are high-priced and luxury models. And it appears the higher the price, the more likely a buyer is to get it.

For example, Borenius said up to 80 percent of the V12-powered Mercedes S600 buyers have been adding the optional Keyless Go system. But when other, lower-priced models of S-Class are added in, the percentage drops to about 25 percent.

The S600 starts around $125,000, while the starting price for a base S-Class is around $75,000.

Likely to Go Beyond Luxury Models

Officials expect the technology to spread to lower-priced cars.

"I personally think it's a natural evolution of keyless entry and we'll see more market penetration," Dutter said. "We'll see the same kind of proliferation that we saw in the early '90s when keyless entry [began to spread to lots of cars]."

Bonawitz added that drivers who have the feature appear to want it on their next car, too.

Some Important Tips

But there is a learning curve. For example, this writer found herself exiting the RL and Infiniti's M cars after shifting into Park, only to discover the engine was still running. With no key to turn and remove from the ignition and put in my hand, I had to retrain myself to stop stepping out of the car until I pressed the engine button on the dashboard.

Valet parking is another situation that can require retraining, since a valet driver will have no way to start the vehicle once it's parked unless he or she has a fob, too. Yet many car owners are likely to exit their cars and leave with their fobs in their pocket or purse. The engines remain on and the valets can drive the cars away for parking. But once the vehicles are turned off, the valets will have no way of restarting them without the fobs.

"What we have seen is when people see it, at first, there's a little hurdle," Holman said. "It may take a couple weeks or a month [to adjust]."

Smart key systems don't require regular maintenance, and the fob batteries, which are generally akin to those used for watches, should last up to three years, officials said.

Still, replacing a Keyless Go fob will cost more than an old-fashioned key would because the fob includes technology, Borenius said. Officials at Mercedes and Toyota said the price for replacement fobs could be $200-plus.

In addition, when one of these fobs is lost, a car owner can't just call up the dealer and get a new one right away. For example, at Mercedes, the fobs are customized to each car, so an owner must go to a dealer, show proof of ownership of the car, and then order a new fob, which is produced at an off-site, secure facility and then shipped to the dealer. This could take a couple days, though the process can be expedited with express delivery service, according to Michelle Murad, a Mercedes-Benz product public relations specialist.

Ann Job is a freelance auto writer.

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