A temporary loss of boost pressure ruined Toyota’s near-perfect Le Mans run, costing the team its presumed victory on the very last lap.

What should have been one of the greatest triumphs in the long history of the 24 Hours of Le Mans turned into heartbreak in the last few minutes of this year’s race. The #5 Toyota TS050 prototype was running beautifully, cruising to victory, only to mysteriously lose power on its last lap of the circuit. And now we know what caused this heartbreaking failure.

Toyota just released a postmortem on its Le Mans tragedy, and it doesn’t do much to quell theheartbreak of the team’s defeat. Apparently, a connector between the turbo and the intercooler failed, which caused a “loss of [turbocharger] control.” Presumably this means that the turbo lost boost pressure, causing a loss of power that let Porsche snatch victory from the strong-running Toyota team.

The team was able to “modify the control settings to restore power,” but not quickly enough to complete the last lap in under six minutes, a Le Mans racing requirement. This led the #5 car to be “not classified” in the final race result, effectively taking away any shot at a podium finish.

Toyota doesn’t yet know why this part failed, but it’s conducting an investigation to prevent the same problem from occurring again later in the World Endurance Championship season.

The fact that Toyota’s defeat apparently was the result of a small part failure only makes the situation more sad. The #5 car ran a near-perfect race, only to have the tiniest failure take it away from them in the final minutes. Just the latest reminder that, in racing, everything counts.