Investigation Opened Into Prius Brake Problems

The Transportation Department has opened an investigation into brake problems in the 2010 model year Toyota Prius after the Japanese automaker acknowledged design problems with the brakes in its prized gas-electric hybrid.

The National Highway Traffic Safety Administration told The Associated Press it has received 124 reports from consumers, including four reports of crashes. The investigation will look into allegations of momentary loss of braking capability while traveling over uneven road surfaces, potholes or bumps.

The Japanese government has ordered Toyota to investigate brake problems. The automaker said it had corrected problems with the antilock brake system in Prius models sold since late last month, including those shipped overseas.

The flaw requires a software programming change to fix.

Toyota acknowledged that is has begun fixing problems with the brakes in its prized Prius, but remains undecided about a recall, adding to the catalog of safety woes — and muddled responses — at the Japanese automaker.

The automaker, already reeling from massive global recalls involving faulty gas pedals in other cars and trucks, said Thursday that Prius models sold since late last month, including those shipped overseas, had the problem with the antilock brake system corrected.

But that still leaves the potential flaw in Priuses sold in Japan and overseas before late January. And while Japan's transport minister urged Toyota to consider a recall of the Prius — the world's top-selling gas-electric hybrid — and said he is ordering an investigation into the brake problem, Toyota executive Hiroyuki Yokoyama said the company hasn't yet decided whether a recall is necessary.

Toyota acknowledged the brake problem while reporting a $1.7 billion profit for its October-December quarter.

The remodeled gas-electric Prius hybrid went on sale in the U.S. and Japan in May 2009. Complaints about braking problems in the Prius have been reported in the U.S. and Japan, combining to some 180, and come amid a recall of nearly 4.5 million vehicles for faulty gas pedals.

The flaw makes the brakes momentarily unresponsive. Toyota was checking if there were reports of similar problems with other hybrid models though they use a different braking system from the Prius.

Paul Nolasco, a company spokesman, said the time lag for brakes kicking in felt by drivers stem from the two systems in a gas-electric hybrid — the gas engine and the electric motor.

When the car moves on a bumpy or slippery surface, a driver can feel a pause in the braking when the vehicle switches between the traditional hydraulic brakes and the electronically operated braking system, he said.

The brakes start to work if the driver keeps pushing the pedal, but the driver may momentarily feel they aren't working, he said.

A major Toyota dealership in Tokyo said the automaker had informed dealers that Prius brakes can sometimes fail to work for less than a second but it had not told owners.

"It is disappointing because the Prius was receiving such rave reviews," said Hiroyuki Naito, a manager at the dealership. The latest model Prius hit showrooms last May and is only made in Japan.

In recent weeks, the automaker had answered questions about its overseas recalls for gas pedals with assurances that problems didn't extend to Japanese vehicles, implying it was doing a better job with quality control in Japan.

But Prius owners were worried.

Akira Suzuki, 25, who makes surf boards and teaches surfing, was excited about the high mileage his recently purchased hybrid offers — but concerned about its possible problems.

"I'm not sure how safe it is. I plan to drive very carefully," said Suzuki, who lives in a Tokyo suburb.

Despite snowballing problems with quality, Toyota reported Thursday a $1.7 billion profit for the October-December quarter, citing healthy sales of its green models including the Prius, and predicted it would return to profit for the fiscal year through March.

Toyota shares tumbled on the Tokyo Stock Exchange, falling 3.5 percent to close at 3,280 yen ($36) after plunging 5.7 percent the previous day. Since Jan. 21, when the U.S. recalls were announced, the stock has lost about 22 percent. In the U.S., Toyota's American depositary shares fell about 1.2 percent to $72.67 in premarket trading.

The automaker has received 77 complaints in Japan about braking problems for the Prius. Separately, the Japanese government confirmed 14 complaints. About 100 complaints over Prius brakes have been filed in the U.S.

At least one accident has been reported in Japan suspected of being linked to faulty braking. In that accident, in July 2009, a Prius crashed head on into another car, slightly injuring two people, according to the transport ministry.

Toyota had looked into that accident and concluded there were no problems with the Prius.