Japanese car giant Toyota has apologised to its customers and says a piece of steel about the size of a postage stamp will cure the accelerator problem that led to the worldwide recall of millions of vehicles.
The 30-minute repair programme would start in a matter of days in the US, the company said.
Toyota insisted the solution, rolled out six days after it temporarily stopped selling some of its most popular models, had been through rigorous testing and would solve the problem for the life of the car.
After a week in which Toyota drivers said they were worried about the safety of their cars and dealers were frustrated by a lack of information, Toyota said it would work to regain the trust of its customers.
"I know that we have let you down," Jim Lentz, president of Toyota Motor Sales USA, said in a video address.
The repair involves installing a steel shim a couple of millimetres thick in the pedal assembly, behind the top of the accelerator, to eliminate the excess friction between two pieces of the accelerator mechanism.
In rare cases, Toyota says, that friction can cause the pedal to become stuck in the depressed position.
Toyota said car owners would be notified by post and told to make appointments with their dealers. It said cars already on the road would get priority.
The recall covered 4.2 million cars worldwide and 2.3 million in the US, including some of Toyota's best-selling models, such as the Camry and Corolla. It has recalled millions more because of floor mats that can catch the accelerator pedal.
Jeffrey Liker, a University of Michigan engineering professor who has studied Toyota for 25 years, said he believed the fix would work.
"They are under the gun. They aren't playing any games," he said, referring to the car maker's reputation for careful testing and engineering.
Toyota would not give an estimated cost for the repair work but estimated repairing all the recalled cars would take months.
It said some dealers were planning to stay open around the clock once parts arrived.
Etienne Plas, a spokesman for Toyota Motors Europe in Brussels, said the car maker would implement the same remedy for faulty accelerator pedals in Europe, but he did not know when.
Besides millions of dollars a day in lost sales, the recall posed a public-relations challenge to Toyota, which for decades has enjoyed a loyal customer base and a reputation for quality.
Toyota says it will have a failsafe system in most of its models by the end of this year and all models by the end of 2011, so that the accelerator goes to idle if the brake is pressed at the same time.
US safety expert Clarence Ditlow, executive director of the Centre for Auto Safety in Washington, said Toyota may be rushing out a fix without considering other potential sources of the problem, such as the electronics of the pedal system.
"Toyota is betting their reputation that this is the last and latest fix that will correct the problem," he said. "If it doesn't, they are in a world of trouble."
But Toyota said it was confident the problem was mechanical.
A Toyota executive said today there were no electronic problems in vehicles being recalled in the US for the accelerator pedal problem and that the earlier recall for floor mats was "totally unrelated".
Toyota Motor Corporation executive vice president Shinichi Sasaki, who oversees quality control, said there was a perception the company was slow in responding to the accelerator pedal problem but it had made finding a fix a priority.
Although the recalls were announced on January 21, it was not until yesterday that a US executive appeared in public to outline details of what had to be fixed.