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Toyota's Troubles Put EMI Back Into The Spotlight

Pondering Toyota's recalls, EMI, avionics, and Steve Wozniak, not particularly in that order.

3 min read

Toyota's Troubles Put EMI Back Into The Spotlight

It’s the floor mats. No, it’s sticky pedals. It’s definitely not the electronics.

That’s what Toyota says about the sudden acceleration problem that led to the recent raft of recalls. But some drivers, newspaper reporters, and engineering professors have their doubts, indicating that interference from electronic devices, built into the car, carried into the car, and even outside the car could be causing the problem.

Toyota has said it proved its point by having an outside firm test the electronics on various car models. The firm reportedly fooled around with engine power and various controls within the car seeing if some odd combination created a surge, but could not generate the problem; Toyota’s press releases about the test didn’t say a word about EMI.

Ahhh, does this bring back memories. Back in the ‘90s, a growing reliance of new aircraft on electronic controls was on a collision course with a growing tendency of passengers to bring multiple personal electronic devices on board. A theoretical potential for interference certainly existed—that’s why air passengers are asked to turn off all electronic devices during takeoff and landing, for those are the most unforgiving parts of the journey. And lots of folks thought—and still think—this restriction is silly.

I reported on this with my colleague Linda Geppert back in 1996, for the article “Do Portable Electronics Endanger Flight,” (IEEE Spectrum, September, 1996). And our conclusion was that yes, electronic devices can cause trouble.

However, that trouble is hard to create on cue. The culprit devices perhaps had to be a little out of spec, generating just a little more RF interference than it should—maybe one that slipped out of the factory that way, or one you dropped and thought had escaped damage. (In personal experience, my husband once had to take a new laptop back because turning it on took out the picture on the TV in the next room.) The position of the device mattered—move it around in the plane and the effect would come and go.

Here’s an example of one report we pulled from a database kept by NASA’s aviation safety reporting system, quoted from the article:

In March, 1993, a large passenger aircraft was at cruise altitude just outside the Dallas-Fort Worth International Airport when the No. 1 compass suddenly precessed 10 degrees to the right. The first flight attendant was asked to check whether any passengers were operating electronic devices. She said that a passenger in seat X had just turned on his laptop computer.

The report continues, “I asked that the passenger turn off his laptop computer for a period of 10 minutes, which he did. I then asked that the passenger turn on his computer once again. The No. 1 compass immediately precessed 8 degrees to the right. The computer was then turned off for a 30-minute period during which the No. 1 compass operation was verified as normal.”

So yes, RF emissions from electronic devices can cause weird things to happen. Is it happening in the Toyota case? Toyota says no. And, to date, no real evidence says otherwise.

But if I were Toyota, I sure would be checking it out. Because it does look suspicious.

Which brings me to Apple co-founder Steve Wozniak. The Woz has been complaining that his Prius occasionally surges randomly when it’s supposed to be holding steady under cruise control. My first reaction when I heard this was that he was setting up good story to give to the next cop who tickets him for speeding.

And then I remembered: the Woz is a gadget frea'. He inevitably is carrying multiple smart phones (never just one) and countless other consumer electronic gadgets. His friends love to surprise him with gizmos they’ve picked up in other countries that are not yet available in the U.S. And whenever I run into him he immediately shows me his current favorite gadget.  There is no way he turns off all these devices every time he gets in his car. He’s a walking RF fog.

So here’s a suggestion for Toyota. Forget those expensive outside research firms testing your electronics. Line up about a hundred cars, hook up everything electronic that you can measure, and then just let Woz walk by. If his presence has absolutely no effect, then I’ll believe that it’s a “mechanical problem.”

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