The collision was reported about 4:38 a.m. near De Soto Avenue, according to a CHP incident log. Whether anyone was injured in the pileup was not immediately clear.
Debris was strewn across the freeway and traffic was backed up to Tampa Avenue in the aftermath of the crash. Commuters were urged to use Ventura Boulevard as an alternative route.
All lanes were reopened shortly after 6 a.m., the CHP said.
The cause of the incident is unknown.