Firefighters responding to a report of a traffic accident found the silver, 2010 Mercedes S600 about 100 feet down a brushy ravine about 3 a.m., Fire Department spokesman Eric Scott said.
The car was running and its lights were on. Nobody was inside, and it showed no signs of forced entry, authorities said.
Sheen's publicist Stan Rosenfield said he believed the keys were in the ignition, but police would not confirm that information. Rosenfield declined to comment further, citing the ongoing police investigation.
Someone apparently took the luxury car from Sheen's driveway, where it was parked Monday, and the star of TV's "Two and a Half Men" didn't know it was missing, police Officer Norma Eisenman said.
Officers impounded the vehicle to fingerprint it, she said.
The car was found in the same area off Mulholland Drive where another Mercedes owned by Sheen was found on February 5.
The black, four-door car apparently was stolen from Sheen's garage and pushed or driven over the cliff, where it came to rest upside down. Sheen had left the keys inside.
A Bentley was later found off the same road. Police said they received reports of three other car break-ins in the area.
No arrests have been made.
Famed Mulholland Drive winds along the top of the Santa Monica Mountains through the tony ridge and canyon neighborhoods overlooking the city.
Archie Kapp, a neighbor of Sheen, told KTLA-TV he thinks both cars were taken by the same thieves.
"When they bring it here, they know the spot. They know exactly where they're going and they say 'Hasta la vista, baby,' and it's gone," Kapp said.
