The incident began with a traffic stop at Boston Avenue and Foothill Boulevard at about 1 a.m. near La Crescenta.
Upon contacting the driver, police say the suspect pulled out a handgun and the officer fired at the suspect.
The driver then fled in his vehicle, which was last seen in the area of Tujunga.
It was unclear whether the suspect was struck by gunfire.
The investigation and search for the driver remained ongoing.