The officer is believed to be in critical condition.
The shooting happened in the area of Landale Street, just east of Laurel Canyon Boulevard, on Campbell Hall Episcopal school property just before 8 p.m., CHP said.
Witnesses told ABC7 that the CHP officer attempted to pull over a car but the driver initially refused. Eventually, the driver and officer pulled into the parking lot at Campbell Hall Episcopal, a private K-12 grade school, and then shots were fired.
A description of the suspect was not available.
Video from AIR7 HD showed multiple law enforcement units congregated in the area as they canvassed for clues.
AIR7 HD followed an ambulance, believed to be carrying the officer, from the scene to Cedars-Sinai Medical Center. The ambulance was escorted by several police units.
A large police presence surrounded an apartment complex in the area of Saticoy Street and Haskell Avenue in Van Nuys, where the shooter is believed to be holed up.
A car matching the suspect vehicle description was found near the apartment complex.
It was not immediately known if anyone had been arrested.
The investigation is ongoing.