Ferrari's drivers have said that the team have fixed a technical problem that ruined their weekend in Malaysia.
The Italian team looked strongest overall at Sepang, but Sebastian Vettel was left last in qualifying with a turbo problem that seemed to repeat itself on Kimi Raikkonen's failed car on the grid.
Reports said that the problem was a carbon tube, with the power units all returned to Maranello between Malaysia and Japan for a fix.
"I think we have a good understanding of what happened," German Vettel said, insisting that he still has a chance of beating Lewis Hamilton to the championship.
"It has only been a couple of days but some parts went back and I'm pretty sure it shouldn't be an issue here."
Raikkonen agreed: "We fixed the problem, but no-one can guarantee that it won't happen again."
Also at Maranello, Ferrari repaired superficial damage to Vettel's gearbox, following his bizarre post-race crash at Sepang with Lance Stroll.
Vettel admitted that he is relieved he will not take a penalty.
"We will only find out after we put the gearbox on the car on Saturday, but judging from what I heard, everything should be fine," he said.
However, a slightly more panicked reaction to Sepang had reportedly been made by president Sergio Marchionne, who hinted that organisational changes would occur.
"I heard about it," Vettel said. "Or I read it in the press. I'm not sure if his words were taken out of context.
"I know what is going on inside the team. There is no panic - no emotional reaction to what happened. As far as I know, no big changes are planned."
Vettel is 34 points adrift of Hamilton heading into Sunday's race.
