Lohan said she slammed on the brakes of the Porsche but the car did not stop before hitting the large truck she said cut her off in June.
A source, whose name was not reported, told TMZ when Porsche heard of her excuse, workers asked the company that rented Lohan the vehicle if they could run tests on the brakes.
The allegedly faulty brakes passed and showed no signs of malfunction, TMZ said Saturday.
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