Paul Walker's Baby Mama -- Big Drinking Problems

The mother of Paul Walker's 15-year-old daughter appears to have serious alcohol issues -- TMZ has learned, she was arrested for DUI in August and that wasn't her only one -- and it's a major reason why Meadow moved away from her mom to live with Paul.

Rebecca Soteros was first arrested for DUI in 2003 in Orange County. She pled guilty and was sentenced to 3 years probation.

History repeated itself last year, when Soteros was arrested again for DUI in Hawaii. That case is ongoing.

Sources close to the family tell TMZ ... Rebecca's drinking has been an ongoing issue for years. Paul's daughter Meadow called her famous dad in 2011 and pleaded to let her move to L.A. and live with him. He happily obliged, because we're told Paul and Rebecca had countless arguments for years over her drinking problems.