The #26 G-Drive Racing Oreca Gibson entry has been stripped of its LMP2 class victory in this year's 24 Hours of Le Mans race.
A mighty performance from Jean-Éric Vergne and team mates Roman Rusinov and Andréa Pizzitola had kept the car at the top of the class for much of the race.
However, post-race technical scrutineering found that the car had utilised an illegal device on its refuelling rig to speed up pit stops.
"An additional machined part not featuring in the drawing is inserted into the flow restrictor," said a bulletin from the stewards.
It said that the part had had the effect of "changing the wetted restrictor surface described by the regulatory drawing.
"The technical delegates provided the stewards with photos of the restrictor, the referenced part and its assembly to the 'dead man valve'," the bulletin explained.
"The contested part is a machined part that extends from the dead man valve and inserts inside the cone of the flow restrictor."
Race officials determined that this had given the #26 a significant advantage in the race.
"[Technical delegates] started their investigation of the competitor’s refuelling system following the race when they noted the competitor was able to refuel significantly faster than any of their competitors."
The stewards therefore decided to exclude the G-Drive car from the results, stripping it of its race win.
It means that the #36 Signatech Alpine driven by Nicolas Lapierre, André Negrão and Pierre Thiriet takes victory in the LMP2 category. The #39 Graff-SO24 Racing Oreca of Tristan Gommendy, Jonathan Hirschi and Vincent Capillaire is also promoted to second place.
Having believed that had just missed out on the top three, the #28 TDS Racing Oreca driven by Loic Duval, Matthieu Vaxiviere and Francois Perrodo has moved up one position.
And the United Autosports' #32 Ligier piloted by Juan Pablo Montoya, Will Owen and Hugo de Sadeleer is now classified in fourth place in LMP2, eighth overall.
However, Vergne and the team have confirmed their intention to appeal the disqualification.
"After a year of work & commitment from G-Drive Racing we have been disqualified from Le Mans for a reason that we believe was unfounded," Vergne said on Twitter.
"However we intend to appeal the decision and get back the Victory we all fought for and deserved.
"This is part of motorsport, sometimes you have to run another race to prove we did the right things and keep moving forward never giving up.
"In any case working with [G-Drive] was absolutely incredible and I can’t thank them enough for such a hard work and success we had so far," he added, also expressing his gratitude to his fans.
"Thank you all for the amazing support last week, you are fantastic!"