Teairra entered a guilty plea Monday to one count of operating a motor vehicle while under the influence ... and she's avoiding time behind bars, at least for now.

According to the Queens District Attorney's Office ... Mari has been ordered to complete several DWI-related courses -- including a victim impact panel and an impaired driver program -- and she must install an ignition interlock device in her car, which will remain in place for the next year.

Teairra's license is also suspended for 6 months, and if she fails to comply with the terms of her sentence, we're told she could face up to a year behind bars.

We broke the story ... NYPD busted Mari for DWI back in June, pulling her over after an officer observed her Dodge Charger was missing a front wheel as she drove out of the Midtown Tunnell. Police say she reeked of booze, and her bumper was dragging on the ground, with sparks flying all around her car.

It's not her first brush with the law ... she was convicted of DUI way back in 2011 in Los Angeles.