An electrical fault caused the blaze that killed Cape Town toddler Vanilla Nurse, forensics expert David Klatzow said on Monday.
Vanilla, the daughter of satirist Justin Nurse, died of burns after the family car caught fire last week.
Klatzow, who investigated at the request of the family, said there had been a fault in the window winder switches of the vehicle, a Honda Jazz.
Though the car had been taken to a Honda workshop, it could not be fixed immediately, as parts had to be ordered.
"That developed into an outright major overheating of the circuit board and set alight the plastic alongside," Klatzow said.
The fire broke out in the driver's door of the car, he said.
He had notified Honda about his finding, and the company had been "very grateful for the openness".
Honda SA spokeswoman Joline Dabrowski said the company was aware that Klatzow had released findings to the media.
It had asked him for a written copy of his report, and would comment after that.
The accident happened on Wednesday, Vanilla's second birthday, when the car was parked outside the Nurses' Fish Hoek home.
Nurse's wife Camilla had been shopping for groceries for Vanilla's birthday party, and was carrying bags into the house when the fire broke out.
Vanilla was still strapped into a car seat.
Her mother was burned as she attempted to free the child, who was dead when she arrived at hospital.
The Nurses gathered with friends and relatives to mark her birthday on a family farm near Stellenbosch on Sunday.
Vanilla, the daughter of satirist Justin Nurse, died of burns after the family car caught fire last week.
Klatzow, who investigated at the request of the family, said there had been a fault in the window winder switches of the vehicle, a Honda Jazz.
Though the car had been taken to a Honda workshop, it could not be fixed immediately, as parts had to be ordered.
"That developed into an outright major overheating of the circuit board and set alight the plastic alongside," Klatzow said.
The fire broke out in the driver's door of the car, he said.
He had notified Honda about his finding, and the company had been "very grateful for the openness".
Honda SA spokeswoman Joline Dabrowski said the company was aware that Klatzow had released findings to the media.
It had asked him for a written copy of his report, and would comment after that.
The accident happened on Wednesday, Vanilla's second birthday, when the car was parked outside the Nurses' Fish Hoek home.
Nurse's wife Camilla had been shopping for groceries for Vanilla's birthday party, and was carrying bags into the house when the fire broke out.
Vanilla was still strapped into a car seat.
Her mother was burned as she attempted to free the child, who was dead when she arrived at hospital.
The Nurses gathered with friends and relatives to mark her birthday on a family farm near Stellenbosch on Sunday.