Accident Reconstruction Network > News > August 2007

Accident Reconstruction News Article

The Toyota Prius Hybrid continues to generate complaints of unintended acceleration episodes suggesting the possibility of a serious flaw in the vehicle's computer system, electronic controls or software program.

Toyota service technicians have dismissed the dangerous events as driver error or nothing more than a floor carpet jamming accelerator pedal.

ConsumerAffiars.Com readers who have experienced these harrowing events disagree.

Last week, we reported the story of a brand-new Prius with only 600 miles on the odometer that suffered from “uncontrollable acceleration” on a freeway near Everett, Washington.

Now, Ben in Walnut Creek, California writes: “I had a very similar case with the Prius owner you mentioned in your lemon of the week.” Ben said he was “coming up on a red light and there was a large crease or bump in the road."

"When my Prius hit the bump in the road the traction control systems kicked in, and at the same time the brakes felt unresponsive and the car felt as if it was accelerating or lunging forward,” he said.

Ben said the he almost rear-ended the car in front of him.

ConsumerAffairs.Com first reported the unintended acceleration problem with the Prius early last year, when one of the popular hybrids rampaged out of control on a Michigan highway, endangering the driver as well as those nearby.

At the time, the incident was the second known incident involving uncontrolled acceleration in the computer-controlled Prius. The driver of the 2005 Prius, Herbert of Battle Creek, Michigan, experienced a probable software problem.

He found it necessary to speed up while passing a slower vehicle on the highway. The problem began after he passed the slower car and tried to slow down.

"I let off the accelerator and pressed the brakes several times, but the vehicle continued to accelerate under full power," Herbert said at the time.

Toyota recalled the Prius hybrids to examine the software but the unintended acceleration reports are continuing.

“Twice, on July 29, 2007, our 2006 Toyota Prius took off like a rocket in circumstances just like Herbert's wild ride in Michigan last October,” Irwin in Studio City, California writes.

His Toyota service manager told Irwin that no one has ever had this problem before and Toyota is unable to recreate the unintended acceleration.

The service technician was either uninformed of intentionally misleading his customer, since ConsumerAffairs.Com has received -- and published -- numerous such complaints.

And while the Toyota service manager may not be familiar with the problem, Marvin in Los Lunas, New Mexico certainly is.

“I have had an incident of acceleration, beyond what was commanded, in my Toyota Prius two times. The cause is unknown,” he wrote.

"In each case, the vehicle was accelerating at a rate below maximum and went to and stayed at maximum without driver command.” Marvin told ConsumerAffairs.Com.

“A simple touching of the lever that disengages the cruise control caused the system to immediately go back to a normal condition with the cruise control off,” Marvin told us.

Marvin said he is “a qualified professional engineer and systems analyst.” His work “has involved automobiles as well as aircraft and industrial systems.”

”I can assure you,” Marvin told ConsumerAffairs.Com, “that the incidences that I had did not involve mechanical sticking or jamming of the accelerator pedal because of a piece of carpet. It was not driver error.”

In Marvin’s opinion, “the problem may be in the cruise control system itself, either a mechanical, electronic or electrical problem in the cruise control system.”

”The problem could easily cause a serious accident if the driver, caught unaware, did not take immediate remedial action,” according to our reader in New Mexico.

Toyota did not respond to requests for comment.

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