Amanda Stevens only wanted to go home for lunch, but within minutes of stepping into her Audi Q3 last Saturday, she found herself trapped inside the car and struggling to breathe.
The keyless-entry car had locked her in. It was 41 degrees outside, she was in a car park and she did not have a phone to call for help.
I was a wreck. I nearly died
"I got in, shut the door, went to press the start button and a message came up saying 'key not identified'," Ms Stevens, from Noosa, Queensland, said.
"All the doors locked themselves. I thought 'that's not good' ... I tried to wind the windows down and open the doors. When that didn't work I started to panic. I was trapped.
"Within a couple of minutes I was struggling to breathe inside the car, because it was parked in the sun."
She began waving to passers-by and bashing on the car windows for help. After about 12 minutes, she caught the attention of a man walking past, who managed to open the door from the outside.
Audi spokeswoman Anna Burgdorf said there were no known faults with the Q3's locking mechanism and Audi had towed the car away to investigate what had happened.
Ms Stevens said she wanted to know what had gone wrong with the car. She had not driven it since and said the incident could have been tragic.
"I was a wreck. I nearly died," she said.
"I was really lucky that I didn't have a baby or any children in the car."
Fairfax Australia motoring editor Toby Hagon became trapped inside a Porsche - with his child - in a similar incident in 2010.
Technicians determined that electronic interference had blocked signals from the Porsche's wireless smart key and that had caused the doors and windows to lock.
Porsche spokesman Paul Ellis said at the time that "external interference is not something that can be completely eliminated and you do get black holes where interference is possible".
The Porsche Panamera uses a smart key similar to Ms Stevens' Audi.
An Ambulance NSW spokesman said it was rare for paramedics to treat adults stuck in cars.
But he said children trapped in hot cars could suffer "damage to body cells leading to unconsciousness, shock, organ failure and death". Adults were less likely to be injured.
-Fairfax News Australia