Some Toyota owners have begun complaining that their vehicles suddenly accelerated even after dealerships made repairs to fix the problem, according to reports filed with federal safety regulators.
At least seven complaints, filed in the last two weeks with the National Highway Traffic Safety Administration, allege that after the recall service to modify pedals and replace floor mats the cars still surged out of control.
Although the allegations are unverified by the agency, they are a worrying sign that the nearly 10 million recall notices issued by Toyota may not fully address the problem of unintended acceleration -- which some believe is caused by problems in the electronic throttle system, rather than mechanical issues involving pedals.
NHTSA has said it will review Toyota electronics to see whether they are a potential cause, and the automaker has commissioned a private study of its throttle system.
The safety agency said that it had begun to investigate the new reports of recurring sudden acceleration on Tuesday. "NHTSA has already started contacting consumers about these complaints to get to the bottom of the problem and to make sure Toyota is doing everything possible to make its vehicles safe," said David Strickland, NHTSA administrator.
"There is already doubt out there that the solutions Toyota has put forward really fix the problem of unintended acceleration," said Aaron Bragman, auto industry analyst at IHS Global Insight. He cautioned, however, that the complaints should be thoroughly investigated before definitive conclusions are drawn.
In one report, the owner of a 2010 Camry that was repaired Feb. 12 in Michigan said the car accelerated up a snowbank five days later. It had received special brake override software as part of the recall, the complaint said.
"Had the incident happened one minute earlier, I would have been in a high car/pedestrian area and would not have been able to avoid an accident," the anonymous consumer wrote. "The fix done by Toyota is not the fix for the acceleration problem."
In addition to the seven reports of sudden acceleration, several other complaints in the NHTSA database reported unusual vehicle behavior, such as errant check-engine lights, after the recall service.
The reports were first noted by Safety Research & Strategies, a vehicle safety consulting firm in Rehoboth, Mass.
The Japanese automaker is recalling 5.4 million cars and trucks because of a potential for the floor mats to trap the accelerator pedal, as well as 4.1 million vehicles with a gas pedal that can stick. Some vehicles are subject to both actions.
On Tuesday, Toyota executives appeared before Congress for the third time in the last week, telling the Senate Commerce Committee that it had designed "effective and durable solutions" for the problem and that its dealers had repaired more than 1 million vehicles through the recalls.
Under those recalls, Toyota is swapping out floor mats, replacing and modifying pedals and removing floor padding. It is also adding brake override software -- designed to automatically reduce the engine to idle when both the brake and the accelerator are depressed -- to seven models affected by the floor mat campaign.
Toyota spokeswoman Celeste Migliore said she was not aware of specific complaints alleging that sudden acceleration had recurred despite receiving the repair, but said the automaker closely monitored the NHTSA database.
"We very much would like to have any of those individuals who claim they've had unintended acceleration after the fix go back to the dealership," Migliore said. "If there was an accident, we want to see the vehicle and the driver and the accident report."
The number of complaints to NHTSA has skyrocketed since Toyota announced in late January that it would temporarily halt sales and production of eight models of cars and trucks following its announcement of the sticking pedal recall.
Those filings, many of which concern incidents from years earlier, have driven up counts of accidents in Toyota-related sudden acceleration events. On Tuesday, NHTSA said it now had reports of 52 fatalities in such accidents, up from 34 just a few weeks ago.
A concern among safety experts is that the brake override software, which has been described as a final solution to the problem of unintended acceleration, may in fact cause more problems by adding a new layer of software to the system.
"These fixes are not dealing with the root causes of the problem," said Sean Kane, president of Safety Research and Strategies.
The newly filed complaints claiming recurring sudden acceleration include incidents involving the Avalon, Camry and Matrix. Those models are currently being given the brake override software as part of the recall, along with the Lexus IS and ES. No complaints about post-repair incidents in the IS and ES were found in NHTSA databases as of Tuesday.
Last week, Toyota said it would expand the reach of that upgrade, which it calls "an additional measure of confidence," to the Venza, Tacoma and Sequoia.
Among the other complaints was one involving a 2009 Camry in Massachusetts that "still does not respond immediately to de-accelerate" after the driver's foot is taken off the pedal, even though it was taken in under the recall Feb. 22. Another described a 2008 Avalon in Atlanta that was repaired but only a few days later "accelerated on its own and . . . did about 3 loops around the garage area of the home causing damage to the car, benches, tree, bushes, lamp post, etc."
Some consumers don't allege unintended acceleration but say the fixes created other problems in their vehicles.
A 2007 Camry driver from Sherrill, N.Y., for example, said that since the repair, the car idles fast in reverse, cruise control does not disengage properly and various check engine lights come on. The owner of a 2005 Avalon in Houston, meanwhile, said that following the recall service, his wife stepped on the gas and found that nothing happened, causing it to lose speed on the highway.
During Tuesday's hearing, Sen. Maria Cantwell (D-Wash.) argued that until the definitive problem causing unintended acceleration was identified, the fixes implemented in the recalls, including brake override, would not solve the problem.
"It is not really a solution as much as it is a fail-safe strategy," Cantwell said.