The National Highway Traffic Safety Administration (NHTSA) today announced it is opening a formal investigation of the Toyota Prius Hybrid model year 2010 to look into allegations of momentary loss of braking capability while traveling over an uneven road surface, pothole or bump. The agency received 124 reports from consumers, including four alleging that crashes occurred. Investigators have spoken with consumers and conducted pre-investigatory field work.

Just tonight it was announced, on CNN, that Lexus hybrids are being added to the list. Lexus hybrids use the same hybrid synergy drive that the Toyota Prius uses. Toyota told CNN that it was checking the brakes on the Lexus vehicles — as well as a Japanese model called the Sai.

Toyota has announced no recall of these vehicles, however, and said it has not received any complaints about the brakes from consumers.

The complaints on the 2010 Toyota Prius have been as detailed as this one that I found on safercar.gov, the website to go to complain about safety issues:

“On three occasions, while driving on clean, dry road surfaces, my 2010 prius suddenly and briefly accelerated without any warning after I drove over minor bumps and, on 1 occasion, a manhole cover, while braking. The sensation was that of the engine suddenly surging and accelerating. I was fortunately able to apply harder pressure to the brake pedal, regained control of the vehicle and avoided crashing into the car in front of me. I spoke with a Toyota field technical specialist today who told me that the mechanics of the car are such that if a wheel hits a bump or moves onto a surface that causes it to rotate at a different rate versus the other wheels, the car thinks it is going into a skid, and the ABS system kicks in. also, the system that generates energy to recharge the battery, which also effectively brakes the car, suddenly ceases to operate. consequently, you have the sensation of acceleration when in fact, according to the Toyota specialist, the car stopped decelerating. nonetheless, this sudden deceleration is unexpected, and if i was not focused at those exact moments and failed to immediately apply significant pressure to the brake pedal, i could have easily crashed into an object, or car, or person, in front of me. i do not feel safe in this car, and am worried that my wife or son could have a major problem responding to this sudden lack of control. there is great potential for serious injury or death from this type of incident. my car is about 1 month old, with 1,250 miles on it. i understand from the specialist that toyota dealerships on long island have had at least one other similar complaint.”

The Japanese government has ordered Toyota to investigate the brake problems. Toyota said it had corrected problems with the antilock brake system (ABS) in Prius models sold since January 2010, including those shipped overseas. The flaw is a software program that will need an update to fix.

Ford recalls hybrid

A 30-year testing engineer for Consumer Reports slowed for a stop sign at the turnoff to their test facility in East Haddam, Connecticut, the brake pedal went unexpectedly further down than normal but the car barely slowed. The engineer zoomed through the turn, with brake-system warning lights illuminated on the dash. The car more or less coasted to a stop, with what the engineer described as minimal brake feel.

Consumer Reports called Ford and they already had a service bulletin (TSB-09-22-11) in response to that problem. The service bulletin said that electronic interference might cause the electronic brake-by-wire module to switch itself off temporarily. If that happened, the braking system would revert to a backup conventional hydraulic mode that preserved braking capability, but the pedal would drop over an inch. When the engine is restarted, the electronic braking system would resume.

Sounds like a computer that freezes and you have to reboot.

Ford engineering representatives explained that the software threshold for establishing a fault in the regenerative brake system was set too sensitively, causing the system to transition to conventional brakes when it was not necessary.

Ford estimates that approximately 18,000 2010-model Ford Fusion and Mercury Milan Hybrids could be vulnerable to the electronic brake-software glitch but only a tiny fraction will ever exhibit it.  Ford explained, “The software threshold to transition from regenerative brakes to conventional brakes can cause the system to transition to conventional brakes unnecessarily.”

In a statement, Ford said, “We have received reports that some drivers have experienced a different brake feel when the hybrid’s unique regenerative brakes switch to conventional hydraulic braking. They may initially perceive the condition as loss of brakes even though the vehicle has full braking capability. When this occurs, our system maintains full conventional brakes and full ABS function.”

Ford added, “There have been no injuries related to this condition.”

If you own a Fusion or Milan Hybrid made on or before October 17, 2009 have your local dealer perform the brake-system software update specified by Ford’s “Customer Satisfaction Program 10B13.”

Thanks for the help Consumer Reports


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