BAR have insisted that they did not deliberately run an underweight car during the San Marino Grand Prix.
The team was cleared by race stewards after Jenson Button's car was found to be too light, but F1's ruling body the FIA has appealed against the decision.
BAR team boss Nick Fry said: "This team is owned by two blue-chip international corporations with huge integrity.
"Does anyone really think that we would deliberately do anything against the rules? We've hidden nothing."
Stewards spent six hours examining Button's car after the British driver finished third at Imola on Sunday, and eventually gave it the all-clear.
But the FIA decided to appeal, and the case will be heard by its International Court of Appeal in Paris on 4 May.
If BAR - owned by British American Tobacco and Japanese carmaker Honda - are found guilty then sanctions could range from Button being stripped of his third place to the team being thrown out of the championship.
Button's car was found to be 5.4kg under the minimum 600kg weight limit, and the rules say cars have to comply at all times.
It prompted suggestions from some F1 insiders that BAR might have used a second, concealed fuel tank to retain fuel pumped into the car during the final pitstop.
But Fry said the stewards had been given access to all BAR's data, adding that BAR used a high-pressure fuel system which needs a collecting device to run the pump.
"The FIA has seen the device and inspected it several times before. They are fully familiar with the system," he said.
F1 is going through a period of deep division, with manufacturers threatening to set up a rival series.
And the team bosses involved in the breakaway threat warned before the start of the season that they expected intense scrutineering of their cars and possibly even disqualifications.
"Given the political situation in the sport we are concerned about everything," said Fry.
"We are hanging on to the basic belief that right will prevail at the end. At no time was the car light and I don't think that we've done anything wrong.
"This is F1, the pinnacle of motor racing and it is very competitive. We're all aware of that, we're all big boys.
"If anyone is trying to destabilise us, that will not work. We're bigger than that."