Toyota Motor Corp. said Thursday it found design problems with the antilock brake system and corrected them for Prius models sold since late January, including those being shipped overseas.
But the company said it was still investigating how to inform customers who had bought them earlier. Nothing was decided on that front for Prius gas-electric hybrids sold outside Japan, according to Toyota.
Complaints about braking problems in the Prius — the world's top-selling hybrid — have been reported in the U.S. and Japan, combining to some 180, and come amid a global recall of nearly 4.5 million vehicles for faulty gas pedals.
"We are investigating whether there are defects in the Prius," Toyota executive Hiroyuki Yokoyama told reporters at the automaker's Tokyo headquarters.
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. Fixing that included a software programming change, he said.
Whether a recall was in the works for the Prius is still undecided, according to Toyota, but the transport minister urged the company to consider it and is ordering an investigation.
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.
Earlier in Washington, U.S. Transportation Secretary Ray LaHood startled the public with a comment, which he later retracted, that Americans should park their recalled Toyotas unless driving to dealers for accelerator repairs.
The Prius was not part of the recall spanning the U.S., Europe and China over sticking gas pedals in eight top-selling models including the Camry. That recall involved 2.3 million cars in the U.S. alone.
Toyota senior managing director Takahiko Ijichi defended the automaker's quality standards.
"We have not sacrificed the quality for the sake of saving costs," he said. "Quality is our lifeline. We want our customers to feel safe and regain their trust as soon as possible."
Toyota for the first time gave an estimate of the costs of the global gas-pedal recall. The $2 billion total represents $1.1 billion for repairs and $770 million to $880 million in lost sales.
Toyota is expecting to lose 100,000 in vehicle sales because of the recall fallout — 80,000 of them in North America.
The tarnishing of the Prius nameplate is also a serious setback for Toyota's recovery from the global auto slump.
"It's very unclear what the future will bring," said Mamoru Katou, auto analyst with Tokai Tokyo Research. "Toyota's image as a leader in hybrids has been hurt."
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.
In the U.S., harried dealers began receiving parts to repair defective gas pedals in millions of vehicles and said they'd be extending their hours deep into the night to try and catch up. Toyota said that would solve the problem — which it said was extremely rare — of cars unaccountably accelerating.
Toyota is set to face additional questioning from U.S. congressional and other government investigators. Toyota has shut down several new vehicle assembly lines and is rushing parts to dealers to fix problems with the accelerators, trying to preserve a reputation of building safe, durable vehicles.
The latest recall involves 2009-10 RAV4 crossovers, 2009-10 Corollas, 2009-10 Matrix hatchbacks, 2005-10 Avalons, 2007-10 Camrys, 2010 Highlander crossovers, 2007-10 Tundra pickups and 2008-10 Sequoia SUVs.
U.S. lawmakers who are now digging into the recalls say they would look into the Prius.
Many consumer groups have questioned whether Toyota's gas pedal fix will work and have asserted it could be connected to problems with the electronic throttle control systems.
Yasuaki Iwamoto, auto analyst with Okasan Securities in Tokyo, said the big challenge for Toyota was rebuilding its damaged brand, especially in overseas markets.
"For all people who own Toyota cars, for all people with jobs related to Toyota, this huge sense of uncertainty simply isn't going away," he said.
Associated Press writers Ken Thomas, Stephen Manning, Larry Margasak and Andrew Taylor in Washington, and Shino Yuasa in Tokyo contributed to this report.