F1 teams Brawn, Toyota and Williams will find out on Wednesday if their cars are legal.
The trio face an appeal over the legality of their rear diffuser designs, with lawyers representing the teams involved arguing their cases on Tuesday and Wednesday.
Brawn GP and Jenson Button have won both races of the season so far, while Toyota and Williams have both scored points. However, those results remain provisional pending the outcome of today's hearing by the FIA's International Court of Appeal.
The FIA and the stewards in Australia and Malaysia have already deemed the rear diffusers to be race-legal, but this has been questioned by BMW Sauber, Ferrari, Red Bull and Renault.
However, BMW has already admitted that it has started developing a new diffuser that could be implemented, depending on the outcome of the appeal, and all the other teams are believed to be undertaking similar design studies.