Drivers experienced delays on the Southbound carriageway after the lanes were closed between junctions 30 and 29 at around 6.30am today.
Four fire engines from Chorley, Leyland, Bamber Bridge and Penwortham were called to fight the blaze using a hose reel and breathing apparatus.
One of the closed lanes re-opened after around an hour.
The remaining lane re-opened at around 10.30am after a complex vehicle recovery was completed, say Highways England.
Police and fire services warned drivers to approach the scene with caution as smoke was drifting across the motorway and affecting visibility.
Force Incident Manager for Lancashire Police Nigel Barraclough said: "Drivers should take care when driving in the area as the foggy weather and smoke may cause visibility issues. Avoid the area if possible to do so."