Ferrari insists it is not suffering any problems with its engine, despite the reliability niggles that have marred its pre-season testing.
Speculation that Ferrari could be facing issues with its power unit ramped up at this week's Barcelona test when both Kimi Raikkonen and customer team Haas faced reliability dramas on the opening days.
But after arriving at the Barcelona test on Wednesday, Ferrari team principal Maurizio Arrivabene has dismissed talk of any concern at Maranello.
"Ferrari does not have an engine problem," he told Motorsport.com. "I can say that officially."
New Vettel engine
Ahead of Sebastian Vettel's return to the car on Wednesday, Ferrari has elected to make its first power unit change of the testing sessions so far.
The power unit that has been used up until now is being shipped backed to Ferrari's factory where it will be put on the dyno for checks about its reliability over the distance that engines must complete in 2016.
Arrivabene added: "That engine has not finished its life cycle, so it was sent to Maranello where it will continue testing on the dyno.
"The same will be done with the current power unit that is mounted in the car of Vettel."
It is understood that Ferrari wants to find the breaking point of the 059/5 during the dyno simulations rather than on track, and that the recent dramas with the fuel system, and issues related to MGU-K packaging, are being put down to teething troubles.
Interview by Franco Nugnes