Sebastian Vettel is down to four power units for the remaining 19 races this year, following his smoky retirement on the parade lap in Bahrain.

Earlier, Ferrari media insider Leo Turrini had said that the problem had been traced to an injector, but he has now clarified that the fault was actually caused by "a bug on the electronic mapping".

That is good news for the Maranello team, as the fix will presumably be easier.

"It was an electronic problem rather than the failure of a mechanical part," agreed a report in La Repubblica.

The report explained that the electronic glitch occurred in a certain gear at precise revs "causing a sort of blackout that affected the engine" so badly that it was damaged "irreparably".

"In China, Seb switches to power unit two," Turrini wrote in a follow-up post on his Quotidiano blog.

Meanwhile, La Gazzetta dello Sport reports that Ferrari is working on an innovative system for its F1 power unit called HCCI that would help the team track down Mercedes's power advantage, particularly in qualifying.