Edward Vazquez of Corona was struck at Citron Street and Lincoln Avenue about 4:30 p.m. Thursday, according to the Corona Police Department.
Det. Dan Clary said Edward was riding his bike through the intersection when the driver of a sedan ran into him, though the exact circumstances remain under investigation.
The motorist, who was not hurt and whose identity was not disclosed, immediately stopped and waited for first responders to arrive.
The boy was taken to Riverside Community Hospital, where he succumbed to his injuries less than an hour later, according to Clary.
He said that alcohol or drugs do not appear to be factors in the fatality.
The driver was questioned but not arrested, Clary said.
Anyone with information was asked to contact the police Traffic Bureau at 951-817-5784.