A panel of judges is meeting in California to decide whether thousands of car owners can bring a single multi-billion dollar lawsuit against Toyota.
Toyota has had to recall eight million vehicles worldwide in recent months because of possible accelerator pedal problems.
The hundreds of separate cases include dozens of personal injury claims as well as requests for compensation.
Lawyers for Toyota and those suing the car firm have asked for more than 200 claims to be heard as a single case.
Both sides are asking a legal panel to consolidate the cases so that they are examined together by the same judge.
The Toyota recalls were due to a range of possible defects, including inadvertent acceleration caused by sticking pedals, some of which became trapped in floor mats.
A separate recall involved the Prius, when drivers reported intermittent brake performance in some circumstances.
According to Toyota's lawyer, the cases have common issues and there will be significant overlap.