The incident occurred near Dumiyani village in Upleta taluka of the district, over 200km from here, when the car driver spotted sparks near the dash board.
He lost control over the vehicle, causing it to fall in a dry canal while crossing a small bridge near Dumiyani, said Police Inspector of Upleta R S Chavda.
"Car driver Jusab Kharoch, who survived the accident, told us he lost control after seeing sparks near the dash board. The car fell into the dry canal from the bridge," he said.
"The car caught fire immediately after hitting the ground. Three of the passengers got trapped inside the car and were charred to death, while two others managed to escape with injuries. We called fire tenders to douse the blaze and later pulled out the charred bodies," Chavda said.