A mother who left her 7-year-old son locked in the trunk of a car while she partied in a bar has pleaded guilty to child abuse and false imprisonment.

Sarah Powell, 27, and her boyfriend, Jake Faria, 30, entered their pleas Monday as part of a plea bargain.

The charges carry maximum prison terms of up to six years, but the couple are likely to be sentenced to probation at a Jan. 5 hearing with credit for time served, according to San Diego Superior Court Judge Browder Willis.

Both were jailed for several weeks after their arrests.

Powell was arrested during her birthday celebration on Aug. 23 at a bar in San Diego's Ocean Beach neighborhood. A witness had alerted police that the boy was in the trunk of Powell's Volvo, which was parked outside.

The boy was found in the trunk with a pillow and a sleeping bag. Police said Powell told them she put the boy in the trunk for safekeeping when she was unable to find a babysitter.

Faria, who is not the boy's father, was arrested a few days later.

Powell's lawyer, Mary Ellen Attridge, said Powell exercised bad judgment, but that she and Faria otherwise have taken good care of the boy. "She has been a very good mother," Attridge said.

The boy is living with a foster family, but Powell is attending parenting and substance-abuse programs and is working to regain custody, Attridge said.