Hayley pled no contest to one count of driving under the influence -- law enforcement sources say she blew .14. As part of the deal, she got 3 years probation, and was ordered to pay a $390 fine ... and she must complete a 90 day alcohol program.

Also, an ignition interlock system will be installed in her car -- meaning she'll have to blow into a breathalyzer for the vehicle to even start.

TMZ broke the story ... Hayley was arrested for DUI in L.A. last month. Cops found her passed out behind the wheel of her Mercedes on a freeway off-ramp.

Cops said the 24-year-old 'Sharknado' actress reeked of booze and bombed a field sobriety test.