The fire was initially reported shortly after 11:30 a.m. on southbound Highway 680 near the off-ramp to state Highway 262.
The fire prompted the closure of multiple lanes of the highway, CHP and fire officials said.
No injuries were reported. Fremont fire officials said as of 12:20 p.m. that the fire was out and a tow truck was at the scene.
The blaze prompted the closure of the five right lanes of southbound Highway 680. Only the far left lane remained open.
CHP officials said a fourth lane may be open at about 4 p.m.