Martha Daniels, of Litcham, Norfolk, was found lifeless and frothing at the mouth in a car seat, the inquest in Dereham, Norfolk, heard. Her mother Sarah Daniels, 24, said she left the girl in the car outside a house at Sporle, Norfolk, in September 1997, while she completed some cleaning work.
The coroner, Oliver Frankl, recorded an open verdict after hearing that doctors could find no clear cause of death.
Mrs Daniels wept as she told the hearing that she parked the car at the back of the house in Sporle leaving Martha awake and strapped in her car seat in the back. She said it was not a particularly warm day and that she had wound down the driver's window to allow air into the car. She started work at around 8.30am and looked out of the window at 20-minute intervals to check on Martha. At about 9am she noticed the child had fallen asleep. She completed her work at about 11.30am and went back to the car to drive home.
Mrs Daniels said she found Martha lifeless and sweaty in the back and drove straight to her doctor's surgery in Litcham, which was about 15 minutes away. A doctor at the surgery pronounced Martha dead minutes after she arrived.
A pathologist told the hearing she could not say for certain why Martha had died.
A police spokesman said there was no question of criminal proceedings being taken, but he said parents should be wary of leaving children in cars.Reuse content