The problem: The computers running the state-of-the-art electronics in his $80,000 car were full of bugs. The car owner, who can't be identified because BMW insisted he sign a confidentiality statement when the company bought back his car, isn't alone. Thanks to the latest electronics, cars can tell you the pressure in each tire, display stock quotes or give directions to the nearest Italian restaurant. But the complex computer systems required to do all that have broken down on hundreds, perhaps thousands, of luxury vehicles, wreaking havoc on the lives of their owners.

"People have reported total electronic shutdowns to us attributed to the network in the 7-series," says Donald Buffamanti, founder of AutoSpies.com, which bills itself as "the ultimate insiders guide to the world's best automobiles." Adds Buffamanti: "Service specialists who have decades of experience fly to dealers to look into these malfunctions and sometimes they can't figure out what happened." The problems show up on high-end cars because they get the most whiz-bang gadgetry first. That adds insult to annoyance because owners have spent so much on their wheels. Complaints about BMW 7-series and Mercedes-Benz E- and S-class cars range from disconnected calls on built-in phones to seats that adjust without warning while cars are moving, to engines that shut down at highway speeds.

Computers associated with high-tech goodies and government-mandated safety features are increasingly the target of consumer complaints. Electronics were the source of 14 percent of complaints late last year from new-car owners, up from 8 percent in 1987, according to consulting firm J.D. Power and Associates. Fernando Castro says the 2003 Mercedes E 500 sedan he bought last January from a Florida dealership has been in the shop at least 12 times for electronic problems, including a faulty phone and fuel gauge, the latter of which has left him stranded and out of gas. Warnings from his tire-pressure monitor send him to the service station every few days to check his pressure. "Why does it have a computer that reads the problems if they can't fix them?" he asks.

Buffamanti says he's heard from at least 500 owners of 2002 7-series and about 200 owners of 2001-03 Mercedes who say dealers bought back their cars after they complained about problems with electronics. Both companies asked the customers to sign nondisclosure agreements, so several people who discussed their experiences with USA Today would not allow their names to be used.

BMW says it has ironed out most of the major problems with the 7-series.

"There have been some start-up problems with the new generation of electronics, and specifically the iDrive, but sales and research show that the car is meeting and exceeding expectations," says BMW spokesman Gordon Keil. "There is a not-uncommon shakedown period of one to two years with technology this new." IDrive is BMW's computer system that controls navigation, phone and stereo.

Mercedes says it has increased product testing 50 percent and has largely solved problems with its system, known as Comand.

"Quality is an important part of our heritage; it is one of our core values," says Stephan Wolfsried, director of vehicle electronics and chassis for the Mercedes Car Group. "That is why we are aggressively addressing the real — as well as the perceived — issues."

New-car quality, in fact, is at an all-time high, but complaints about electronic accessories have stalled automakers' efforts to improve their quality scores, J.D. Power studies show. Electronics problems, for instance, are offsetting gains from improved engines.

Luxury car owners aren't the only ones affected by quirky computers. Warning lights are flashing, often needlessly, on the dashboards of every brand sold in America. Even basic cars have computers that control most of what makes them go.

"Engine lights come on so easily, and many times they can only be reset by a dealer even if there is nothing wrong," says Dave Hurt, president of Certified Car Care, a company that sells extended warranties. "Diagnosis of problems is a lot more complicated these days because of the amount of electronics in a car."

John Nielsen, director of AAA's approved auto repair network, says it's little surprise that things are going wrong and some of the problems are hard to fix. The new Audi A8L, for example, has 36 computers with 1,600 trouble codes, he says. "These things make the space shuttle look antiquated."

Among the electronics:

• Several 2004 models come equipped with a government-mandated warning system that tells a driver when pressure in one of the tires is low. But it also can give false readings, too many readings and raise the costs of tire replacement and routine maintenance, according to several car and tire company officials. When certain tires are placed on rims with the warning system, they can block the signal and render it useless.

• Emission control systems that have been setting off "check engine" dashboard lights since the 1996 model year now have about 700 possible trouble codes. A problem as simple as a loose gas cap can prompt a warning light.

• A dead battery can wipe out the trouble codes, making it impossible to perform state-ordered emissions testing on a car. The owner may have to drive the car for a few days to replenish the codes, then return for the test.

• More advanced air bags being phased into new vehicles have monitors that can set off an SRS (for "supplemental restraint system") light. One luxury-car owner says it took a dealer 19 hours to reset the computer after his light went on.

Wolfsried says the increasing demand for safety, comfort, performance and lower emissions can't be achieved without advanced electronics. But J.D. Power's surveys show that while people are demanding advanced safety features, they are not asking for as much technology as they are getting.

Erik Berkman, an executive engineer at Honda, acknowledges that some of the new features in the Acura TL — such as locks that can be programmed to each driver's specifications — are an example of the market pushing new technology rather than responding to consumer demand.

"Some people see it as just one more thing that can go wrong," Berkman says.

The new Cadillac XLR sports car can be started without a key as long as the electronic key is nearby. And, like some Mercedes models, it has "adaptive cruise control," which maintains a set distance from the car in front to make highway driving less tiring. Cadillac tested pre-production versions of the XLR for more than 1 million miles — twice what's usual — to make sure the systems would be as trouble-free as possible.

"When we first went to electronics, everything we did added a wire," says David Leone, who has been a Cadillac engineer for 24 years. "But with every connection, there was an opportunity for a problem."

Leone, chief engineer on XLR, says Cadillac now uses fewer wires and more redundant chips to keep malfunctioning computers from creating problems. Cadillac also is adding technology aimed at cutting the number of hassles for drivers. For instance, motorists who have General Motors' satellite communications system and get a check-engine alert can get the problem diagnosed remotely. It's the same for cars with the Mercedes satellite communications system.

Wolfsried says it is better to have a safety feature such as a tire pressure monitor, "and understand that it increases complexity, than not to have it at all."

BMW's Keil suggests that even though some of the early adopters have suffered as the kinks are worked out, customers win in the long run.