Championship leader Nico Rosberg was called to see the stewards about a possible breach of yellow flag rules during the lap in which he won pole position on Saturday at the Hungarian Grand Prix.
Rosberg edged out his teammate and nearest title rival Lewis Hamilton to score pole at the Hungaroring by 0.143 seconds, his final flying lap being completed partly under yellow flags following a spin for Fernando Alonso.
The German summoned to stewards after failing to slow through double yellow flags on final lap.
FIA explained regulation about yellow flags
Single waved: Reduce your speed, do not overtake, and be prepared to change direction. There is a hazard beside or partly on the track
Double waved: Reduce your speed significantly, do not overtake, and be prepared to change direction or stop. There is a hazard wholly or partly blocking the track and/or marshals working on or beside the track.
The stewards announced they were investigating more than three hours after the rain-hit session ended, making it possible Rosberg could be penalised and lose pole position.