Toyota Prius brakes now under invesitgation

Toyota Prius brakes now under invesitgation

It’s just going from bad to worse for Toyota. First came complaints of cars running away without the driver pressing the accelerator. Now the Japanese government has ordered Toyota to investigate the braking system on the 2010 Prius.

The U.S. government has also decided to investigate the matter after receiving over 100 complaints about the brakes on the third-generation hybrid. The Prius uses a special electro-hydraulic brake system that blends the regenerative and friction braking functions. There complaints in Japan and North America all state the same issue – a momentary loss of braking power at low speeds on slick or bumpy road surfaces.

Although it’s uncertain what exactly the problem is at this stage, experts suspect it may be a software issue. The problem surrounds the complex regenerative braking system that captures kinetic energy by using a computer to apply pressure.

Because the behavior of friction brakes varies over time depending on temperature, moisture, wear and other factors, it is very difficult to calibrate the hi-tech brakes. The fact that this it’s happening at low speeds shows that the wheel speed sensors are becoming less accurate at low speeds as the time period between sensor pulses is extended.

If these are the problems that the Prius is experiencing, they may be corrected with an update to the control software. However, that will take time for Toyota to calibrate and validate. Until then it’s all hands to the deck at Toyota to wriggle out of this next jam.

Car and SUV road tested the 2010 Toyota Prius recently and experienced no issues with the braking system. Click here to read the Toyota Prius iTech review.

It’s just going from bad to worse for Toyota. First came complaints of cars running away without the driver pressing the accelerator. Now the Japanese government has ordered Toyota to investigate the braking system on the 2010 Prius.

The U.S. government has also decided to investigate the matter after receiving over 100 complaints about the brakes on the third-generation hybrid. The Prius uses a special electro-hydraulic brake system that blends the regenerative and friction braking functions. There complaints in Japan and North America all state the same issue – a momentary loss of braking power at low speeds on slick or bumpy road surfaces.

Although it’s uncertain what exactly the problem is at this stage, experts suspect it may be a software issue. The problem surrounds the complex regenerative braking system that captures kinetic energy by using a computer to apply pressure.

Because the behavior of friction brakes varies over time depending on temperature, moisture, wear and other factors, it is very difficult to calibrate the hi-tech brakes. The fact that this it’s happening at low speeds shows that the wheel speed sensors are becoming less accurate at low speeds as the time period between sensor pulses is extended.

If these are the problems that the Prius is experiencing, they may be corrected with an update to the control software. However, that will take time for Toyota to calibrate and validate. Until then it’s all hands to the deck at Toyota to wriggle out of this next jam.

Car and SUV road tested the 2010 Toyota Prius recently and experienced no issues with the braking system. Click here to read the Toyota Prius iTech review.

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