The incident took place last night when a man, identified as Madan Pal Singh, came to his ancestral home in Rabupura area along with his daughter-in-law and grandson, station house officer Rajvir Singh Chauhan said.
Around 11pm they were returning to Faridabad when their car caught fire near Faleda village due to short circuit, he said.
Police and fire brigade team reached the spot and controlled the fire, but the woman and her son died of burn injuries, Chauhan said.