Anatomy of Toyota's Problem Pedal: Mechanic's Diary
What's the real problem behind Toyota's unintended acceleration? Is it simply a sticky pedal, or is the trouble more fundamental? PM senior automotive editor Mike Allen delves into modern car tech, explaining why widespread theories about electrical throttle problems and electromagnetic interference are misguided.
By Mike Allen
Published on: March 3, 2010
Toyota has recalled millions of cars and trucks4.2 million to replace floor mats that might impede throttle-pedal travel, and 2.4 million to install a shim behind the electronic pedal assembly. All of the affected pedal assemblies were made by Canadian supplier CTS. Toyota's boffins have documented a problem that can make a few of these pedals slow to return, and maybe even stick down. Problem solved.
But the media, Congressand personal-injury lawyerssmell the blood in the water. Not to diminish the injuries and a few deaths attributable to these very real mechanical problems, but they're statistically only a very small blip, which may explain why Toyota took so long to identify the issue, especially when it has symptoms similar to the similarly documented floor mat recall. Plus, sudden unintended acceleration (SUA) is notoriously difficult to diagnose because, more often then not, the problem can't be repeated in front of a mechanic. Let's not forget the Audi SUA episode back in the '80s; the National Highway Traffic Safety Administration eventually concluded that there was no mechanical problem. The culprit, as hard as this is to admit, was most likely driver error. To put the issue into context, in the last decade, there were about 24,000 customer complaints about SUA involving almost every major automaker. The NHTSA investigated fewer than 50.
The issue now is whether there's a more insidious problem unrelated to the two recalls already extant. Specifically, whether there's some design flaw in the entire concept of electronic throttle control. Some are questioning whether electromagnetic interference from devices like cellphones could be contributing to the acceleration problems.
