The theory behind electromagnetic interference: Voltage spikes that may interfere with cars' electronic controls can hit when current in a wire is switched, such as when the brake lights go off.

Allegations of unintended acceleration by Toyota models that are not part of the recall and by cars from other automakers have revived debate over whether electromagnetic interference is the cause of such incidents.
The theory is that electrical signals — from sources as diverse as cellphones, airport radar and even a car's own systems — briefly and unpredictably wreak havoc with sensitive electronic controls in vehicles. It's an argument trial lawyers and consumer advocates have made for years.

Automakers contend that vehicle systems are designed with sufficient shielding and redundancy to prevent such malfunctions. They have tested for electromagnetic interference (EMI) and found no evidence of it for as long as plaintiff lawyers have blamed it for crashes. Several acceleration suits filed against Toyota claim an EMI link.

It's virtually impossible to prove EMI caused a crash. Plaintiffs have won just one case arguing that issue alone. But there are enough unexplainable crashes and acceleration incidents to keep the door open to allegations.

The National Highway Traffic Safety Administration now is investigating whether EMI could be a factor in Toyota's sudden-acceleration problems. It is NHTSA's first serious look at EMI in decades, and members of Congress will explore it in Toyota hearings beginning today.

"If these congressional hearings probe deeply enough, they'll discover that the car industry has known from the beginning that the most likely cause of sudden acceleration is internal electromagnetic interference," charges Tom Murray, a Sandusky, Ohio, attorney who has brought dozens of acceleration lawsuits and is writing a book on sudden acceleration.

Toyota, however, says floor mat interference and sticky gas pedals are the causes of unintended acceleration in the more than 8 million vehicles it has recalled in the USA for either problem. It commissioned an outside company, Exponent, in December to look at the electronic throttle controls, which have replaced mechanical gas pedal and throttle systems in most vehicles of all makes since the 1990s.

According to a draft report obtained by USA TODAY, Exponent says it could not induce unintended acceleration through "electrical disturbances."

But Keith Armstrong, a United Kingdom-based EMI expert, argues that the tests weren't comprehensive enough to find whether EMI could be to blame. Two experts consulted by the House Energy & Commerce Committee, which is holding today's hearing, were similarly critical. The panel's leadership called it a flawed report, but Toyota says it is far from final and will be peer-reviewed.

NHTSA says it "has no reason at this point to believe" EMI is causing unintended acceleration in Toyotas. Still, looking at it anew is a turnabout. In 1975, a NHTSA report warned that EMI was a potential problem as electronics, just then being used in cars, became more common. Since then, however, its acceleration studies concluded that driver behavior was to blame and didn't address EMI.

Murray, who says he was contacted by NHTSA defect investigators last month, believes that is a mistake. He blames EMI for all but "1% to 2% of all Toyota sudden-acceleration cases" and most of those in other vehicles, too. At least 14 sudden-acceleration lawsuits alleging EMI are pending, including ones against Toyota.

Onboard EMI sources

While EMI from external sources, such as traffic lights or radar, is possible, it is unlikely because it would require an unusually strong signal, says Brian Kirk, a U.K.-based consultant in software safety systems who advises in auto lawsuits. More likely sources are onboard components, he says, because even very low-power electromagnetic radiation from the car's electronics could cause a problem. He says, for example, that EMI from poorly designed ignition wiring could disrupt signals in the electronic throttle or engine controls.

Internal EMI has been linked, Armstrong says, to high-voltage spikes when current in a wire or coil is switched, such as when the headlights or brake lights go off.

Automakers' move to electronic engine controls, including throttles, has been driven by the need to meet tighter federal fuel and emissions regulations. They allow far more precise control of the engine operation and fuel use. Recent years have seen so-called drive-by-wire systems replacing mechanical control of other critical functions, such as steering assist.

Automakers' quiet concerns

Testing for potential EMI is a closely guarded subject within automakers. But lawsuits over the years have uncovered documents citing internal concern.

Walter Gelon, then an employee at General Motors-owned Hughes Aircraft, warned in early 1987 that he thought EMI was behind reported unintended acceleration in GM vehicles, according to an internal memo obtained by Murray's law firm, Murray & Murray.

"It seems very clear to me that (GM) vehicles have serious EMI problems which are triggering ... unwanted acceleration," Gelon wrote to Hughes colleagues.

But a late 1988 report provided by GM showed Hughes largely ruled out EMI as a cause of sudden acceleration after a lengthy GM investigation.

GM still holds that position. "GM has a robust testing and validation process for electromagnetic compatibility (among systems), and there is nothing past or current that suggests any unwanted acceleration issues related to EMI in our vehicles," says spokesman Alan Adler.

Also in the 1980s, as use of electronics in cars expanded fast, EMI was on the minds of Ford engineers. The minutes of an October 1986 Ford Technical Affairs Committee meeting, provided by Murray & Murray, show Ford looked into whether "electromagnetic influences" were behind an increase in unexplainable electronic component failures.

Spokesman Said Deep said Ford later ruled out "electrical interference problems" and gave dealers better diagnostic equipment and training, which reduced the number of such warranty claims.

Armstrong, who was interviewed this month by NHTSA defect investigators, says "automakers almost never publicly acknowledge EMI problems," but he remains sure they exist.

"Why would (automakers) spend millions of dollars on sophisticated EMC (electromagnetic compatibility) test facilities, and place EMC test requirements on all their electronic suppliers, if it wasn't necessary?" asks Armstrong, who is president of the U.K.-based EMC Industry Association. He was an expert witness in a Ford sudden-acceleration case this month and is advising lawyers suing Toyota.

Armstrong reviewed the Exponent draft report on Toyota's electronic throttles and called it "complete baloney." He asserts that the "redundant" backup sensors the report suggests protect against EMI are ineffective because they are based on the same technology. He believes two different technologies must be used to keep multiple sensors from being affected in the same way at the same time.

Dozens of EMI testing centers

Automakers say they try to test for all possible electronic signals that could affect cars. There are dozens of EMI auto testing facilities in the U.S. and Mexico, including centers owned by GM and Ford.

Lee Hill, founding partner of Silent Solutions, which does EMI testing and consulting on autos says, "Anything with electronics has some vulnerability, but every important system on an automobile is tested very carefully."

Hill says automakers have been testing for EMI since the 1960s, even before electronics controlled vital systems. He says that in addition to testing of onboard systems, vehicles are bombarded in a lab with external radio waves and driven through areas where there is known radio-wave interference.

Ford's Deep says: "We have not seen issues from EMI or any other signal disturbances from external sources. We do also test extensively and rigorously for internal sources. Ford vehicles are designed to prevent unwanted acceleration by protecting against, detecting and evaluating electrical interferences."

Toyota is building an EMI test facility in Ann Arbor, Mich., and already has one in Japan.

"We have never found ... any issue of acceleration from the electronics," Kristen Tabar, general manager of electronic systems for Toyota Motor Engineering and Manufacturing, North America, said Monday during a briefing for journalists on Toyota electronics testing. "If interference did occur beyond what our testing would have found, (the system) would detect it and act appropriately."

Toyota President Akio Toyoda said last week that its cars have "fail-safe" systems that shut the cars down when electrical interferences occur, a feature auto-engineering experts say is now standard in the industry.

Proving anything is tough

Certainty may remain elusive.

Mukul Verma, formerly one of GM's top safety experts, points out that electronic throttle controls may be affected by other electrical and electronic systems, including those in the car, and that unintended acceleration may result from car sensor malfunctions, software glitches or from "electromagnetic interferences, which are random and still not fully understood."

Verma, an adjunct professor of mechatronics (the relationship between mechanical and electronic components) at Lawrence Technological University in Southfield, Mich., points up the difficulty in being able to "rule in or rule out" EMI as a factor in sudden acceleration. "It's just too hard to prove either way. The thing with electrical currents is, once they are done and gone, there's no trace level. You can't reconstruct any phenomenon caused by electrical current going into a computer."

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