Toyota Prius: Unintended Acceleration, Traction Control Problems and Throttle Failure or… Owner Error?

Frank Williams
by Frank Williams has collected complaints from Toyota Prius owners regarding throttle control. One, a new Prius with 600 miles on the odometer, accelerated wildly while the owner was attempting to merge onto a busy interstate. On another occasion, the traction control system (itself another problem reported on the site) kicked in and the car accelerated. A third time the car refused to slow after passing another car. One Prius owner, an engineer, discovered that tapping the lever that disengages the cruise control solved the problem– even though the cruise control system was already turned off. Toyota denies any mechanical or software problem exists. They suggest that a wadded carpet may have caused a sticky go-pedal.

Frank Williams
Frank Williams

More by Frank Williams

Join the conversation
4 of 25 comments
  • Kdhspyder Kdhspyder on Aug 15, 2007

    One must first analyze the source of these reports. Consumer Affairs is a trolling net for anyone who may want to register a complaint, valid (or not) real (or not). To date there are very few complaints by real people with real VINs ( actual vehicles ) at the NHTSA site. The owners first sought out Consumer Affairs to lodge a complaint? I’m skeptical.

  • Almira Almira on Feb 02, 2009

    I had my experience with prius yesterday, got stranded for 30 minutes in the nowhere, because car's engines keep accelerating even with stop brakes, when I set on park and tried to drive - its' contune drive like a crasy. After turned off for 20-30 minutes it started drive normal again. I am going to take today to check it.

  • Ganderc Ganderc on Apr 07, 2009

    I read that they redesigned the braking systems for the 2010 Prius. That appears to be Toyota's response to the fact that the U.S. Generation 2 Prius (2004-2009) has had low-speed brake failures reported to the National Highway Traffic Safety Administration (NHTSA) at 31 times the rate of such failures reported for the 2004-2009 Corolla, which of course has traditional brakes. Many of the Prius low speed brake failures were in low-speed city traffic, resulting in rear-end collisions without injury. It appears that the several computers that control the complex braking systems were too busy calculating the most efficient way to apply the brakes, and did not get around to actually applying them, until it was too late. Toyota never took responsibility for the problem, but the 2010 redesign indicates they were aware of it. Unfortunately, the NHTSA never initiated an investigation despite the extremely high rate of failures. The detailed failure reports ("complaints") are available to the public on the NHTSA website. The details are these: Through March 2009, 2004-2009 Prius has received 44 complaints of low speed brake failure. 2004-2009 Corolla has received 7 complaints of such failures. Given that about five times more Corollas than Prius were sold during 2004-2009, 44/(7/5) = 31 times the rate of brake failure for the Generation 2 Prius. Let's hope the 2010's brakes work!

  • Cooper_mini Cooper_mini on May 05, 2009

    that it real and Toyota know about it ! when I bought my prius the dealer suggested me "don't use cruise control until 3000 miles" because "it might working strange" ... (something like that)