The German failed to make the start at Sakhir after his engine blew up spectacularly on the formation lap, with smoke seen billowing out from the back of his car.

Although initial suspicion had revolved around broken fuel injectors, detailed analysis at Maranello this week has confirmed it was something totally different.

The part that failed was an exhaust valve, but interestingly Ferrari technicians believe that this was the end result of the problem rather than the cause.

They believe that a problem with the engine parameters, linked to electronics management, while it was running at low speed triggered a set of circumstances that pushed the valve beyond its normal operating parameters, and caused the failure.

Ferrari's belief that an electronics issue was to blame would explain why the technicians had not discovered any problem with the power unit before the race.

Had there been any hint of concern then Ferrari would not have hesitated in changing the engine before the start.

New China engine

While the Bahrain retirement was a blow to Vettel, and means he will have to take a second engine for China, the fact that the issue has been traced to electronics means there should be no concerns about there being a fundamental design problem with the power unit.

Measures will be taken for the Shanghai race to ensure that there is no repeat of the dramas for when the Ferrari is operating at low speeds.

The analysis of Vettel's engines also confirmed that there were no similarities between his issue and the turbo failure that put Kimi Raikkonen out of the Australian Grand Prix.