Drivers had been told ahead of qualifying that if they had all four wheels over the white line at the edge of Parabolica then they would have lap times deleted.
During Vettel’ first run in Q3, the Ferrari driver drifted wide at the final corner and, from television images, appeared to have fallen foul of this rule.
But after being summoned by the race stewards to look into the matter, and video footage having been analysed, there was no firm conclusion about whether or not all of Vettel’s wheels had been off the track at the same time.
In the end, amid some uncertainty about the situation, it was decided that Vettel did not deserve to be punished.
A statement from the FIA said: “The Stewards reviewed multiple camera angles, some of which appeared to show that the tyres were not in contact with the white line of the track edge, however other angles appeared to show that part of the front “wheel” (when viewed from above) may have been within the bounds of the white line.
“This cast an element of doubt which is considered significant enough to give the ‘benefit of doubt’ to the driver in question.”
The decisions means Vettel starts fourth for the Italian Grand Prix, pending the outcome of the investigations into the slow driving during the final phase of Q3.