Officials said a good Samaritan was driving by around 3 a.m. and saw the boy standing outside by himself behind a school at Kewen Avenue and Allegheny Street.
"I thought it was a toy or something," said Luis Estrada, who found the boy.
Estrada said he saw the boy crying and called police. The boy was barefoot, wearing just a T-shirt and a diaper.
The child was taken to the police station in Pacoima. He was happy when his mother arrived at the station around 6 a.m.
The mother of the boy was searching for the child when a neighbor saw the boy on the news and alerted the mother, according to police.
Police believe the boy just wandered away from his home while his family was sleeping. They are questioning the mother to find out exactly what happened.
The incident remains under investigation, but police say they do not believe any charges will be filed.