Sudden acceleration: Electronic interference could be a cause

Today's cars use 'throttle by wire' technology, and it's possible that the electronic signals could be jammed by other devices in your vehicle's complex computerized environment.

Tue, Feb 02 2010 at 3:15 PM EST

COLLISION COURSE: Toyota's Matrix, recalled for unintended acceleration. (Photo: Toyota)

Could there be an electronic cause of sudden acceleration embedded deep in your vehicle's sophisticated control system?

It's possible. After a series of inquiries, the federal auto safety agency announced that — despite earlier skepticism — it is investigating electronic interference as a possible cause.

Toyota's massive recalls were the result of sticky accelerator pedals and interfering floor mats, and they've been made more urgent by recent deaths. There have been as many as 2,000 cases of unintended acceleration in Toyota vehicles, and a reported 16 fatalities and 243 injuries. When cars take off by themselves, all causes of unintended acceleration have to be investigated. We turn off cell phones and computers on airplanes because of possible electronic interference, and modern cars could have a related "crosstalk" problem. The culprit may not be your cell phone, but dueling signals generated from inside your car or truck.

To help explain the situation more fully, some background is in order:

Last August, California Highway Patrol Officer Mark Saylor, his wife Cleofe, his daughter Mahalia, and brother-in-law Chris Lastrella were on the road in a 2009 Lexus ES 350, borrowed from their local dealer because the regular Toyota was in the shop.

It was 6:30 p.m. Without warning, the car began accelerating uncontrollably, finally reaching 100 mph on northbound Route 125 in Santee.

Lastrella had a cell phone, called 911, and the following conversation was recorded:

Lastrella: We’re on North 125 and our accelerator is stuck.

911 dispatcher: I’m sorry?

Lastrella: Our accelerator is stuck. We're on 125.

911dDispatcher: Northbound 125. What are you passing?

Lastrella: We’re going 120. Mission Gorge. We’re in trouble. We can't … there is no brakes. End freeway half mile.

911 dispatcher: You can’t do anything like turn off your engine?

Lastrella: We’re approaching the intersection. We’re approaching the intersection. We’re approaching the intersection.

With voices inside the car shouting “hold on” and “pray,” the Lexus slammed into the rear of a Ford Explorer, hopped a curb, and burst through a fence before rolling down an embankment, becoming airborne and rolling several times before bursting into flames in the San Diego River Basin. All four people on board were killed.

The Saylors’ car was equipped with all-weather floormats, which can interfere with the gas pedals under certain conditions. And it had inappropriate ones installed, which increase the likelihood of that being the cause in this case.

Only a few months later, however, just after Christmas, there was a second horrific accident. In Southlake, Texas, a 2008 Toyota Avalon plummeted into a pond after it began racing out of control. This crash also killed four people, members of a Jehovah’s Witnesses group.

The floor mats? They were in the trunk. Weeks after the fatal crash, Southlake police were still baffled as to the cause. “I think they may get there by at least determining what didn't cause the accident, help them at least get closer to the truth,” said Lt. Ben Brown.

It is at least possible that the Texas tragedy was the result of electronic interference with the “throttle-by-wire” systems in modern cars. In other words, there is no direct mechanical connection between the driver’s pedal inputs and the throttle’s response — it’s an electronic connection.

Both Toyota and the National Highway Traffic Safety Administration (NHTSA) say they have thoroughly investigated electronic causes, and Toyota Motor Sales President Jim Lentz said yesterday, “It is not an electronics issue.”

But there is evidence that federal regulators did encounter an issue. In a 2008 report based on an investigation of a 2007 Lexus ES-350, the researchers wrote, “Magnetic fields were introduced in proximity to the throttle body and accelerator pedal potentiometers and did result in an increase in engine revolutions per minute (RPM) of up to approximately 1,000 rpm, similar to a cold-idle engine rpm level.”

Still they went on to conclude that the car’s systems had “multiple redundancies” and “showed no vulnerabilities to electrical signal activities.” In a follow-up phone call, a NHTSA source said that the agency had conducted a “thorough investigation,” but he asked not to be identified.

“The same report said that 600 ES-350 owners were surveyed by NHTSA, and 59 said they’d experienced incidents of unintended acceleration. I was struck by that,” said Jake Fisher of Consumer Reports, who was also looking at the federal report. Fisher also notes that the report found that many ES-350 owners had problems shifting into neutral (because of the car's serpentine shift pattern) and did not know how to quickly turn off the engine (which uses a start button). He advises consumers to follow through with getting their cars fixed if they were subject to the recall, and to familiarize themselves with how to put their cars in neutral and turn off the engine.

There is likely to be more than one thing behind these incidences of unintended acceleration. An electronic cause is championed by Clarence Ditlow, executive director of the Nader-inspired Center for Auto Safety, who dispatched a Freedom of Information Act request to NHTSA in search of documents on its investigation. Examining that data, he said it appears that the agency’s work amounts to less than the thorough investigation cited by the official.

Electronic interference would not leave a trail for investigators to follow. “In some ways it is the perfect defect,” Ditlow said, “because when one examines the vehicle there’s no failed part — such as a stuck accelerator — to find.”

In my own investigations of this issue, I’ve heard many eyewitness reports indicating that the car just suddenly took off — sometimes from idle at a stop sign. This would be unlikely if the cause was a jammed pedal (though it might result from floor mat ingress). The owner of a 2008 Camry LE wrote, “The car started accelerating on its own and forcing the brake pedal down and pumping it wouldn’t stop it. After about five minutes, it settled down and went at regular speed.”

CTS Corp., the Elkhart, Indiana firm that makes the 5.3 million pedal assemblies that Toyota has recalled, makes just this point. “CTS believes that the rare slow return pedal phenomenon, which may occur in extreme environmental conditions, should absolutely not be linked with any sudden unintended acceleration incidents,” the company said.

“CTS is also not aware of any accidents and injuries caused by the rare slow return pedal condition, to the best of its knowledge. CTS wishes to clarify that it does not, and has never made, any accelerator pedals for Lexus vehicles and that CTS also has no accelerator pedals in Toyota vehicles prior to model year 2005.

The company added, “We are disappointed that, despite these facts, CTS accelerator pedals have been frequently associated with the sudden unintended acceleration problems and incidents in various media reports.”

So if the pedals did not cause either the Texas or California crashes, and if the Texas crash involved no floormats at all — what are we talking about here? This is a dramatically unfolding story; expect major developments soon.

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