Toyota Admits: Prius Brakes Can Get Confused On Icy Roads

Bertel Schmitt
by Bertel Schmitt
toyota admits prius brakes can get confused on icy roads

Complaints about allegedly faulty Prius brakes are growing by the minute. This morning’s Nikkei reports that in addition to the 14 complaints received by Japan’s Transport Ministry, dealers in Japan are handling 77. Today, Toyota conceded that the brakes can get confused on icy roads.

As reported yesterday, the NHTSA had received numerous complaints about the brakes of the new Prius hybrid. According a New York Times tally, the NHTS had logged “at least 136 complaints about the brakes on the 2010 Prius. Many are from drivers who say the vehicle surged forward or temporarily lost braking after driving over a pothole or other uneven surface, and many say it is a recurring problem.”

Toyota Executive Vice President Shinichi Sasaki assured Transport Minister Seiji Maehara that a remedy for the brake problem has already been devised. At the same time, Sasaki insisted that Toyota will investigate each complaint.

This Tokyo afternoon, Toyota gave a press conference. Bad news: Toyota is investigating whether any of its hybrids besides the Prius have brake problems. The Sai, which was released in December, and the Lexus HS hybrid use the same electronic braking system as the Prius.

After having received increased complaint in December, Toyota changed the software in January. Also in January, Toyota retooled the braking systems for cars made that month. However, they did not disclose the move. “We were investigating the cause of the problem,” said Hiroyuki Yokoyama, general manager of the Customer Quality Engineering Division, “We did not intend to cover up the issue.”

According to Toyota, the logic of the regen brakes can get confused: “When driving on an icy road, the shift from the electronic brake to the hydraulic brake sometimes takes longer than usual,” Yokoyama conceded.

“At first, we thought the complaints were due to users’ unfamiliarity with the hybrid’s brakes,” Yokoyama explained. “But as it got colder in December, the number of complaints increased. This was when we began to consider a remedy, which we carried out in January.”

But they did not tell previous owners. Braking on icy roads is dicey as it is. You can’t have brakes that haven’t made up their mind whether to brake the old way or the new way.

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  • Panzerfaust Panzerfaust on Feb 04, 2010

    That has to be the epitome of faux-PC doublespeak; instead of a brake failure the brakes were 'confused.' Kinda makes you feel sorry for the poor little Prius, it's a victim too.

  • Sul Sul on Feb 04, 2010

    I've been driving ABS-equipped cars since the early 90's, and I've noticed that the brakes on several of my cars have been easily confused by potholes, washboard surfaces, and ice. ABS on ice almost never works. (I live in New Hampshire.) And potholes and washboard surfaces can cause ABS to activate when you don't need it. I remember standing on the brakes of my '06 Altima while deccelerating downhill off a highway, over a washboard surface, headed toward a traffic light in a busy residential neighborhood, with my heart pounding in terror, as the ABS pumped away and reduced my braking was like these nightmares that I have where the controls of a car stop responding to me. I ended up coming to a stop right on the stop line, my leg cramped with the effort of what should have been a simple stop. My point is, it's not just Toyota's ABS that can interfere with the driver's control of a car. I've been wondering for days if Toyota isn't taking it on the chin just because there are so many Toyotas on the road, and a few strange incidents are causing a widespread moral panic. This ABS thing reinforces that belief. Down with ABS!!! (Except maybe on trucks.) Let's teach people some simple driving skills instead.

    • See 1 previous
    • Carsinamerica Carsinamerica on Feb 05, 2010

      I live in Michigan. My ABS works quite well on ice. I hit the brakes, the car stops, and it doesn't go sideways if I have to apply a steering input.

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