Toyota's popular Prius is one of the marques involved in the 3.8m recall
Toyota says it will make changes to accelerator pedals on 3.8 million already recalled vehicles in the US.
It is the latest attempt to remedy a fault with the pedals which has been blamed for at least one fatal accident.
In September, the car giant advised drivers to remove their floor mats after it warned the pedals could become jammed under it.
In the latest move, Toyota will order dealers to shorten the accelerator pedals while it develops a replacement.
Popular vehicles such as the Toyota Camry, the top-selling passenger car in America, and the Toyota Prius, the best-selling gas-electric hybrid, and the luxury Lexus brand are part of the recall.
The first recall was prompted by a high-speed crash in August involving a Lexus ES350 that killed a California Highway Patrol officer and three members of his family.
The government has attributed at least five deaths and two injuries to floor mat-related unintended acceleration in the Toyota vehicles .
The carmaker and government regulators have been discussing a potential fix for several weeks.
Dealers will begin work on customers' cars in January, with the new pedals becoming available in April. Some vehicles will have brake override systems installed as a precaution.
The company said: "Toyota has and will continue to thoroughly investigate and take appropriate measures to address any defect trends that are identified."