The shooting occurred near 92nd Street and Gramercy Place around 7:40 p.m. on Saturday.
Police said two black males walked up to the SUV and shot the victim, 41-year-old Rene Balbuena of South Gate, three times in the upper torso. He was taken to California Hospital, where he was pronounced dead.
The teenager was a passenger in the SUV. He was treated for a graze wound in the upper arm and was expected to be OK.
Neighborhood residents said they heard at least three loud gunshots and then heard the teen screaming for help. Balvuena was found dead next to the door of his vehicle.
A resident who cared for the wounded teenager until authorities arrived said the teen told her that he and his father had seen an ad for a cellphone on Craigslist and traveled to South L.A. to buy it.
Officials said the investigation indicates the incident was an attempted robbery.
"We're still trying to determine whether in fact the people who placed the ads have anything to do with it," said LAPD detective Chris Barling. "Or if we just have other people who took advantage of some people and tried to rob and was just kind of coincidence that they were at that place at that time."
Balvuena's relatives said he was a hard worker and took good care of his family. The married father was devoted to his two children and helped support other family members.
"He gave everything without asking anything in return, and that's why it's hard for us to lose a good guy," said Jessica Gonzalez, the victim's sister-in-law.
"He was a good person, really, really good person, and I know he's in a good place with God right now. But it's hurting. It hurts a lot," said Ana Guerrero, the victim's sister.
The suspects remain at large. The men, described as two male blacks in their 20s, were last seen running southbound on 92nd Street. Both were wearing dark clothing at the time of the incident.
The deadly shooting broke a nine-day stretch with no homicides in L.A.
Police are urging people to take precaution when responding to ads on Craigslist. In order to avoid being scammed, police say make sure you meet in a public place like a police station.
Anyone with information about this case was asked to contact the LAPD Gang Homicide Division at (213) 485-1383.
City News Service contributed to this report.