Mercedes trackside engineering director Andrew Shovlin has confirmed a faulty sensor was to blame for Lewis Hamilton's formation lap 'stalling' problems.
Heading to the grid for the race start, Hamilton's radio crackled into life with the Mercedes driver reporting an engine 'stalling problem'.
Shovlin explained: "What it actually was, was a sensor issue that was only affecting the engine around the idle controls, so when he was sat there waiting to go off on the formation lap."
As to why Mercedes refused to explain the problem to Hamilton at the time, Shovlin admitted: "We couldn’t tell him it was OK and that’s because of the rules that prevent you talking to the driver during that entire formation lap."
As per regulations, drivers must drive the car "alone and unaided". Therefore, unless there is a question of safety, the engineers are forbidden from making contact with the drivers on the formation lap.