A previous post-mortem examination determined Walker, 40, was killed by impact and injuries related to a fire. The Los Angeles County coroner found that the driver, Roger Rodas, died from impact injuries alone. Both men are said to have died within seconds of the crash, according to media reports.
Walker starred in the Fast & Furious blockbuster films that celebrated high-speed car chases.
Production on the seventh instalment of the Fast and Furious franchise was temporarily halted following his death. Universal Pictures later announced the film's release date would be pushed back several months to April 2015.