Second placed Nico Rosberg has been put under investigation as his Mercedes team advised him on how to avoid a gearbox problem.
The German driver, who had just overtaken Max Verstappen and had closed on Lewis Hamilton lost the use of seventh gear in his Mercedes. Advice given over the radio instructed Rosberg to avoid the failure.
His Mercedes team confirmed that he should shift through the gear, with Toto Wolff confirming after the race that without the intervention it would have meant a terminal failure.
A decision is due after the race from the stewards.