In a statement María's family announced that a forensic doctor had told them that the 33-year-old died "as a consequence of the neurological injuries she suffered" in the accident last year.
María was found dead in a hotel room in the Spanish city of Seville on Friday morning.
The Madrid-born sportswoman, who became a source of inspiration after surviving a near fatal crash last year, was due to share her experiences at a conference in Seville titled 'What Really Matters' as her autobiography Life is a Gift is due to be released on Monday.
"Dear friends, María has left us," read a statement from her family, who plan to bury her in the city she was born in. "She has had to go to heaven like all angels. We are thankful to God for the extra year and a half she gave us."
María almost lost her life in the accident last June when she was doing a test drive for Richard Branson's British team Marussia at Cambridgeshire's Duxford Aerodrome ahead of the British Grand Prix.
But despite suffering serious head injuries and losing an eye in the impact, she recovered and the whole experience had a life-changing effect on her.
"It has taught me that to achieve what you want you have to educate yourself in sacrifice through effort," she said in an interview with HELLO! Magazine's Spanish sister publication HOLA!
"Now I have just one eye maybe I perceive more things than before. Before this, my life was a race against the clock, and now I see you have to stop and measure things in a different way."
María leaves behind her husband, 29-year-old personal trainer Rodrigo Garcia Millan, whom she wed in July and planned to start a family with.