In 2005, Toyota voluntarily recalled 160 000 of its 2004 and some early 2005 model year Prius hybrids because of a software problem that caused the car to suddenly stall or shut down. The time needed to repair the software was estimated at about 90 minutes per vehicle, or about 240 000 person-hours. Even at cost, that is a lot of money.

Last year alone, there were several automotive recall notices related to software problems. For example, in May 2008, Chrysler recalled 24 535 of its 2006 Jeep Commanders because of a problem in the automatic-transmission software. Then in June, Volkswagen recalled about 4000 of its 2008 Passats and Passat Wagons and about 2500 Tiguans for a problem in the engine-control-module software that could cause an unexpected increase in engine revolutions per minute when the air-conditioning is turned on. In November, GM recalled 12 662 of its 2009 Cadillac CTS vehicles for a software problem within the passenger-sensing system that could disable the front passenger air bag when it should be enabled or enable it when it should be disabled. It is a tribute to the automotive software developers, though, that there aren’t many more recalls, given all the software in cars.

The increased use of software has not only affected car warranty costs but has also made cars harder to repair—so much so that insurance companies increasingly find it cheaper to declare cars damaged in accidents total losses than it is to fix them.

It is not hard to understand why. “In a premium car you have 2000 to 3000 singular functions that are related to software,” Broy says. These are then combined into the 250 to 300 functions used by the driver and passengers to operate the car’s systems.

And unlike most commercial aircraft, which have strict firewalls between critical avionic systems and the in-flight entertainment systems, there is more commingling of information between the electronic systems used to operate the car and those for entertaining the driver and passengers. According to a Wharton Business School article entitled “Car Trouble: Should We Recall the U.S. Auto Industry?,” a few years ago, some Mercedes drivers found that their seats moved if they pushed a certain button; the problem was that the button was supposed to operate the navigation system.

Roughly one-third of all the software in cars is devoted just to diagnostics, according to a former automotive engineer I spoke to. But even with all that diagnostic information produced, car mechanics often cannot determine the exact cause of the trouble.

Broy told me that more than 50 percent of the ECUs that mechanics replace in cars are technically error free: They exhibit neither a hardware nor a software problem. Mechanics replace the ECUs simply because they don’t have a better way to fix them, he says.

“The garages and the maintenance people are really at a point where repairing a car is too complex and demanding [for them],” says Broy. Remote diagnostics and repair are likely to render mechanics obsolete for many tasks.

In the not-so-distant future, says Broy, when you have a problem with the computer system in your car, you will go to your garage, where your car will be connected to a network so that off-site OEM specialists can download data, do the analysis, and then upload a software correction.

Voelcker says he wouldn’t be surprised to see onboard systems like BMW’s Assist, Ford’s Sync, and GM’s OnStar soon begin routinely feeding operating data parameters back to centralized systems run by the car manufacturers that will analyze the data for parts drifting out of spec or for software that needs updating and automatically inform the driver that the car needs to be brought in for repair.

Besides monitoring their own internal health, cars are beginning to analyze the world around them. “We’re getting into this era where in addition to sensing what’s going on inside the car, we are using things like radars to detect the presence of external objects, lasers to measure distance for cruise control, and video and ultrasonics to detect objects behind you,” says Little. “The trend will be to extract information external to your vehicle about other vehicles and then exploit this information” to improve safety.For example, cars in front of you will let your car know whether there is ice on the highway or an accident.

Says Little, “We are giving up little pieces of control in exchange for safety. The interesting question is, at what point will you and I be willing to say, ‘Okay. I am not going to drive the car; it is going to drive me.’ ”