Ferrari's Sebastian Vettel gets five-place Russian GP grid penalty

It is believed the gearbox sustained damage in his collision with F1 team-mate Kimi Raikkonen at Turn 1 at the start of the Chinese Grand Prix.

Following practice and investigations in Russia, Ferrari has decided to change the unit.

It caps a difficult day for the German, who stopped on track 30 minutes into the second session with an electrical problem and did not return.

"It looks like we had an electronics problem which is a bit of a shame because we're lacking a couple of laps, especially the long run and race trim to see how competitive we are," he said.

"Kimi did the homework for the team so [it's] not too bad.

"Also in Sochi, we know roughly what to expect so we can still learn a lot from what other people did."

Raikkonen, who finished fourth fastest in second practice, added: "It's not been an ideal day but from my side, we have to work to make the car the way we want.

"I didn't get any good proper laps but it was practice."

Ferrari fitted a new upgraded engine to both Vettel and Raikkonen's car after spending three development tokens.

Speaking about its performance, Raikkonen said: "It's a new one and we wouldn't use it if we didn't expect it to be good."