The report also says no alcohol or drugs were detected in the system of either man on the day of the fiery one-car crash.
It says the Nov. 30 deaths have been ruled accidents and were due to combined traumatic and thermal injuries.
Walker and Rodas crashed on Hercules Street, a major thoroughfare in Santa Clarita, Calif., after leaving a charity event.
The report indicates that Walker's body was badly charred in the accident, and positive identification by visuals alone was impossible.
Investigators found no mechanical problems with the Porsche or problems with the roadway.