Audi dismisses reports that the hybrid system on its Le Mans-winning R18 failed early in the race

The German manufacturer has confirmed that there were problems with the energy-retrieval system on the winning R18 shared by Andre Lotterer, Benoit Treluyer and Marcel Fassler. But Audi Sport boss Wolfgang Ullrich has explained that these were overcome by rebooting the electronics on two occasions before the system was put into what is called 'safety mode' in the closing stages.

"If someone thinks that the winning car — which was one of the quickest in the race, including the last hours — was running without full power, I am honoured," Ullrich told AUTOSPORT.

"The mode we had chosen to be the best for the race was running out of function and we had to reboot the computer system to make it run in the mode we wanted twice during the race.

"It did not cost time because it is something you can do in the pitstop. There is also something called a safety mode and we then went into this mode to make sure we could run to the end without a problem."

Ullrich insisted that safety mode did not mean that the hybrid system was switched off.

"It is a mode in which the system works but not in the mode that we thought was best for the race," he said. "On any electronic system you have a default mode in which it runs safely."

He would not reveal what percentage of its power the hybrid system delivers in safety mode or when the switch was made, although he stated that it was before the lead battle effectively came to an end when Allan McNish crashed the second R18 e-tron quattro in the 22nd hour.

The problems with the system on the winning car did not play a part in the different strategies of the two Audi hybrids: the winning R18 went 11 laps on a tank of diesel, the car McNish shared with Tom Kristensen and Rinaldo Capello was able to go one lap further between fuel stops.

The McNish car, which finished one lap down in second place, encountered no problems with its hybrid system over the course of the 24 Hours.

Read more about this story in this week's AUTOSPORT digital magazine.