The fire was reported before 5:30 a.m. in the southbound lanes south of the Quakertown exit.
State police tell Action News the vehicle caught fire in the left lane.
Police shut down all southbound lanes for about half an hour as firefighters arrived on the scene and put the fire out.
One lane was reopened and traffic was getting by the scene by 6 a.m.
There were no immediate reports of injuries.