January 22, 2010
In a curious twist of timing, Toyota announced another massive recall related to Sudden Unintended Acceleration – this time 2.3 million late model Toyotas plagued with “sticking accelerator pedals.” The timing is suspiciously pre-emptive – the company’s feet were about to be singed an hour later by ABC World News Tonight, followed by a Toyota SUA story on ABC Nightline.
But that is hardly the only odd thing about the recall. In its announcement, the automaker said that it had received “isolated reports” of sticking accelerator pedal mechanisms:
“The condition is rare, but can occur when the pedal mechanism becomes worn and, in certain conditions, the accelerator pedal may become harder to depress, slower to return or, in the worst case, stuck in a partially depressed position.”
Now let’s go the recall population:
How does one wear out the accelerator pedal on a model so new that many are still sitting on showroom floors? (That’s gotta hurt Toyota’s reputation for building a durable product.) And why didn’t any Lexus vehicles make the list? The brands don’t share common parts?
The company’s Part 573 Defect Notification throws a little more light on how exactly are these mechanisms sticking:
“Due to the manner in which the friction lever interacts with the sliding surface of the accelerator pedal inside the pedal sensor assembly, the sliding surface of the lever may become smooth during vehicle operation. In this condition, if condensation occurs on the surface, as may occur from heater operation (without A/C) when the pedal assembly is cold, the friction when the accelerator pedal is operated may increase, which may result in the accelerator pedal becoming harder to depress, slower to return, or, in the worst case, mechanically stuck in a partially depressed position. In addition, some of the affected vehicles’ pedals were manufactured with friction levers made of a different material (PA46), which may be susceptible to humidity when parked for a long period in hot temperatures. In this condition, the friction when the accelerator pedal is operated may increase, which may result in the accelerator pedal movement becoming rough or slow to return.”
Toyota’s chronology outlines a problem that surfaced in March 2007 among their European models, appearing at the time “to be a phenomenon predominantly limited to right hand drive vehicles, without A/C equipment, based on the location of the accelerator pedal and the heater duct. Based on the investigation results above, Toyota lengthened the arm of the friction lever and changed its material to prevent smoothing on all vehicles produced in Europe with the subject accelerator pedals starting in mid-August 2009.”
The problem then drifted over the Atlantic and surfaced in October 2009, where more American and Canadian vehicle owners complained and an internal investigation discovered: the North American models had the same friction lever!
The announcement raises more questions than it answers. Of course, doesn’t explain Toyota’s decision to replace the throttle body and other components in that out-of-control 2007 Avalon, that arrived at the New Jersey dealership with a working pedal, but a stuck throttle.
On the other hand, a sticking accelerator pedal represents some progress from the purely outside agency of a floor mat to an internal mechanical component. Perhaps we’ll get to that electronic explanation yet. As we have noted, there are most likely multiple root causes for Toyota’s SUA problems.
And, we’ve noticed that Toyota’s public posture is likewise evolving. In the past, the company has been quite firm on the point that it knew why its vehicles were accelerating out of control. It was the floor mat, and that was that. Today’s press released ended on an open-ended note:
“Toyota will continue to investigate incidents of unwanted acceleration and take appropriate measures to address any trends that are identified.”
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