The emergency services were called to a vehicle fire on the Princes Highway at Tantanoola at 4.30pm on Monday.
The motorist told police their vehicle had passed over something near the intersection with Kennedy Road and a blaze had started in the engine bay.
They were able to exit their vehicle without injury.
The scene was attended by the Glencoe and Tantanoola CFS Brigades, police and the SA Ambulance Service.