Mercedes and Pirelli will learn Friday if they will face punishment over their involvement in last month's controversial tyre test, following a FIA hearing Thursday in Paris.
If found at fault, the team could be required to forfeit points won, with a maximum punishment of removal from this season's competition.
After more than six hours of deliberation, the president of the International Tribunal convened to hear the case, Edwin Glasgow, confirmed the tribunal judges would need to work into the evening before delivering a verdict.
Mercedes were brought before the hearing on suspicion that they contravened the FIA's ban on in-season testing by using their current car and regular drivers Lewis Hamilton and Nico Rosberg in the three-day, 1,000km test organised last month by Pirelli - Formula One's sole tyre supplier.
Mercedes's defence team claimed they undertook the test to help Pirelli explore what was behind the degradation issues suffered by several teams earlier this season.
Paul Harris, representing Mercedes, said their actions amounted to a "laudable aim" with the purpose of addressing "a Formula One problem". He added that punishing the team for their involvement in that work would be "downright unfair".
However, that view is at odds with Pirelli's take on the purpose of the test, which it claims was 90 per cent focused on tyres being brought in next season.
Mercedes also claim they sought permission from the FIA race director Charlie Whiting before using their current car at the test.
The FIA legal counsel Mark Howard confirmed the governing body did not give Mercedes permission to take part in the test with their 2013 car, branding Whiting's apparent approval "irrelevant".
Key to the Mercedes defence is their insistence that the responsibility for organising and conducting the testing programme rested solely with Pirelli. Harris said: "Pirelli did it all. They were in charge of it all and it's obvious why: it was a Pirelli test."
Mercedes's defence also rests significantly on their assertion that they were given permission by Whiting to use their 2013 car. Running counter to that is Howard's view that Whiting was not authorised to make that decision, adding that such a move could be undertaken only by the FIA's World Motor Sport Council.
Mercedes revealed they had spoken to Whiting in early May to discuss the prospect of using their 2013 car, as they did not have an older car at their disposal.
The Mercedes team principal Ross Brawn called for "perspective" over the significance of the data gathered by his team over the course of the three days.
Brawn, who has previously revealed that the final decision to agree to the Pirelli test was his alone, said access to telemetry data was an "inevitable consequence" of the work being done, but said Mercedes sought to keep their exposure to it "at a minimum".
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