Renault admits it has a clear problem with part of its new power unit which is affecting all of the teams it is supplying.

The three Renault-powered teams - Red Bull, Toro Rosso and Caterham - have completed just 38 laps between them over the first two days of testing at Jerez, while the likes of Mercedes' cars managed 212 laps on Wednesday alone. Head of Renault Sport F1's track operations Remi Taffin confirmed there was one issue that was having to be fixed.

"The fact is that obviously we are facing problems," Taffin said. "There are many problems we can see when we have got new cars and also on our side new power units, so that can be different from one team from another.

Related Articles

"But for sure we know on our side that we had one problem that we clearly identified. We wanted to fix it; we could not fix it for this morning so we decided to do as much as we could on our side to make sure that for tomorrow - especially for Red Bull and Toro Rosso - that we are sure that we can take the track at 9 o'clock. We are confident that tomorrow morning we will have all three cars on track."

Taffin went on to explain that the issue was a hardware problem purely within the power unit and that Renault is confident it has already found the correct solution.

"You have to bear in mind that a power unit is made up of many subcomponents and it's not a matter of any one is not working, it's clearly a problem of integration of all these systems. In particular for this problem we had to fix this problem through the energy store.

"I'm not going to go in to detail due to the nature of the architecture of our system, but we clearly identified something that we would have to change. We've got the parts, we've got the people here, we've got the means to do this. We did not want to do this when we came here but that's what has happened and we are doing it. It is taking time, unfortunately for us it is a bit of high technology - especially when you look at an energy store - so it's something that we have to do carefully, which we are doing, and we are pretty sure that tomorrow morning we will be fine."